Vaccines

Patients who take methotrexate for a variety of immune-mediated inflammatory diseases and pause taking the drug following receipt of a COVID-19 vaccine dose did not have a higher risk of disease flare and had higher antireceptor binding domain (anti-RBD) antibody titers and increased immunogenicity when compared with continuing the drug, three recent studies suggest.

In one study, British researchers examined the effects of a 2-week break in methotrexate therapy on anti-RBD titers following receipt of a third COVID-19 vaccine dose. In their paper published in The Lancet: Respiratory Medicine, they reported results from a randomized, open-label, superiority trial that suggested pausing the drug improved immunogenicity, compared with no break.

In two trials presented at the European Alliance of Associations for Rheumatology (EULAR) 2022 Congress, a team from India set out to determine whether holding methotrexate after receiving both doses of a COVID-19 vaccine, or holding it only after the second dose, was safe and effective. They found that pausing methotrexate only following the second dose contributed to a lower flare risk, and that patients had higher anti-RBD titers when holding methotrexate for 2 weeks following each dose.
 

Pausing methotrexate after booster

The 2-week methotrexate break and booster vaccine dose data in the Vaccine Response On Off Methotrexate (VROOM) trial showed that after a month, the geometric mean antispike 1 (S1)-RBD antibody titer was 10,798 U/mL (95% confidence interval [CI], 8,970-12,997) in the group that continued methotrexate and 22,750 U/mL (95% CI, 19,314-26,796) in the group that suspended methotrexate; the geometric mean ratio was 2.19 (P < .0001; mixed-effects model), reported Abhishek Abhishek, MD, PhD, professor of rheumatology at the University of Nottingham in Nottingham, England, and colleagues.

Prior research showed that stopping methotrexate therapy for 2 weeks following the seasonal influenza vaccine contributed to better vaccine immunity among patients with rheumatoid arthritis, but there was no impact of stopping the drug for up to 4 weeks before vaccination on vaccine-related immunity, the researchers noted.

It is crucial in maximizing long-lasting vaccine protection in people who are possibly susceptible through immune suppression at this point in the COVID-19 vaccination regimen, the study team noted.

“Evidence from this study will be useful for policymakers, national immunization advisory committees, and specialist societies formulating recommendations on the use of methotrexate around the time of COVID-19 vaccination. This evidence will help patients and clinicians make informed choices about the risks and benefits of interrupting methotrexate treatment around the time of COVID-19 vaccination, with implications for the potential to extend such approaches to other therapeutics,” they wrote.

In American College of Rheumatology (ACR) guidance for COVID-19 vaccination, the organization advised against using standard synthetic disease-modifying antirheumatic medicines such as methotrexate “for 1-2 weeks (as disease activity allows) after each COVID-19 vaccine dose,” given the at-risk population and public health concerns, Jeffrey A. Sparks, MD, MMSc, assistant professor of medicine and associate physician at Brigham and Women’s Hospital and Harvard Medical School, Boston, and Sara K. Tedeschi, MD, MPH, assistant professor of medicine at Harvard Medical School, noted in an accompanying editorial in The Lancet: Respiratory Medicine.

However, when the ACR developed this statement, there was only one trial involving patients with rheumatoid arthritis who paused methotrexate following seasonal influenza vaccination, the editorialists said.

Expert commentary

This current study is consistent with other studies over the last several months showing that methotrexate harms both humoral and cell-mediated COVID-19 responses, noted Kevin Winthrop, MD, MPH, professor of infectious disease and public health at Oregon Health & Science University, Portland, who was not involved in the study. “And so now the new wave of studies are like this one, where they are holding methotrexate experimentally and seeing if it makes a difference,” he said.

“The one shortcoming of this study – and so far, the studies to date – is that no one has looked at whether the experimental hold has resulted in a change in T-cell responses, which ... we are [now] recognizing [the importance of] more and more in long-term protection, particularly in severe disease. Theoretically, holding [methotrexate] might help enhance T-cell responses, but that hasn’t been shown experimentally.”

Dr. Winthrop pointed out that one might get the same benefit from holding methotrexate for 1 week instead of 2 and that there likely is a reduced risk of flare-up from underlying autoimmune disease.

It is still not certain that this benefit extends to other vaccines, Dr. Winthrop noted. “It is probably true for most vaccines that if you hold methotrexate for 1 or 2 weeks, you might see some short-term benefit in responsiveness, but you don’t know that there is any clinical meaningfulness of this. That’s going to take other long-term studies. You don’t know how long this benefit lasts.”
 

Pausing methotrexate during initial COVID vaccine doses

Patients with either rheumatoid arthritis or psoriatic arthritis had higher anti-RBD antibody titers when methotrexate was stopped after both doses of the AstraZeneca vaccine, or simply after the second dose, than when methotrexate was continued, according to results from two single-center, randomized controlled trials called MIVAC I and II, Anu Sreekanth, MD, of Sree Sudheendra Medical Mission in Kochi, Kerala, India, and colleagues reported at EULAR 2022.

Results from MIVAC I indicated that there was a higher flare rate when methotrexate was stopped after both vaccine doses, but there was no difference in flare rate in MIVAC II when methotrexate was stopped only after the second dose as opposed to stopping it after both doses.

In the MIVAC I trial, 158 unvaccinated patients were randomized 1:1 to a cohort in which methotrexate was held for 2 weeks after both doses and a cohort in which methotrexate was continued despite the vaccine. In MIVAC II, 157 patients continued methotrexate while receiving the first vaccine dose. These patients were subsequently randomized either to continue or to stop methotrexate for 2 weeks following the second dose.

The findings from MIVAC I demonstrated the flare rate was lower in the methotrexate-continue group than in the methotrexate-pause group (8% vs. 25%; P = .005) and that the median anti-RBD titer was significantly higher for the methotrexate-pause group than the methotrexate-continue group (2,484 vs. 1,147; P = .001).

The results from MIVAC II trial indicated that there was no difference in flare rates between the two study groups (7.9% vs. 11.8%; P = .15). Yet, the median anti-RBD titer was significantly higher in the methotrexate-pause cohort than in the methotrexate-continue cohort (2,553 vs. 990; P = .001).

The report suggests there is a flare risk when methotrexate is stopped, Dr. Sreekanth noted. “It appears more logical to hold only after the second dose, as comparable anti-RBD titers are generated” with either approach, Dr. Sreekanth said.

Expert commentary: MIVAC I and II

Inés Colmegna, MD, associate professor at McGill University in Montreal, noted that it was intriguing that the risk of flares in MIVAC II is half of that reported after each of the doses of MIVAC I. “It is also worth emphasizing that despite the reported frequency of flares, the actual disease activity [as measured by the Disease Activity Score in 28 joints] in patients who did or did not withhold methotrexate was similar.

“MIVAC I and II have practical implications as they help to adequately inform patients about the risk and benefit trade of withholding methotrexate post–COVID-19 vaccination,” Dr. Colmegna told this news organization.

“Additional information would help to [further] interpret the findings of these studies, including whether any of the participants were taking any other DMARDs; data on the severity of the flares and functional impact; analysis of factors that predict the risk of flares, such as higher doses of methotrexate; [and change in] disease activity scores pre- and postvaccination,” Dr. Colmegna concluded.

Dr. Abhishek disclosed relationships with Springer, UpTodate, Oxford, Immunotec, AstraZeneca, Inflazome, NGM Biopharmaceuticals, Menarini Pharmaceuticals, and Cadila Pharmaceuticals. Dr. Abhishek is cochair of the ACR/EULAR CPPD Classification Criteria Working Group and the OMERACT CPPD Working Group. Dr. Sparks disclosed relationships with Gilead, Boehringer Ingelheim, Amgen, Bristol-Myers Squibb, and AbbVie, unrelated to this study. Dr. Tedeschi disclosed relationships with ModernaTx and NGM Biopharmaceuticals. Dr. Winthrop disclosed a research grant and serving as a scientific consultant for Pfizer. Dr. Sreekanth  and Dr. Colmegna have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Patients who take methotrexate for a variety of immune-mediated inflammatory diseases and pause taking the drug following receipt of a COVID-19 vaccine dose did not have a higher risk of disease flare and had higher antireceptor binding domain (anti-RBD) antibody titers and increased immunogenicity when compared with continuing the drug, three recent studies suggest.

In one study, British researchers examined the effects of a 2-week break in methotrexate therapy on anti-RBD titers following receipt of a third COVID-19 vaccine dose. In their paper published in The Lancet: Respiratory Medicine, they reported results from a randomized, open-label, superiority trial that suggested pausing the drug improved immunogenicity, compared with no break.

In two trials presented at the European Alliance of Associations for Rheumatology (EULAR) 2022 Congress, a team from India set out to determine whether holding methotrexate after receiving both doses of a COVID-19 vaccine, or holding it only after the second dose, was safe and effective. They found that pausing methotrexate only following the second dose contributed to a lower flare risk, and that patients had higher anti-RBD titers when holding methotrexate for 2 weeks following each dose.
 

Pausing methotrexate after booster

The 2-week methotrexate break and booster vaccine dose data in the Vaccine Response On Off Methotrexate (VROOM) trial showed that after a month, the geometric mean antispike 1 (S1)-RBD antibody titer was 10,798 U/mL (95% confidence interval [CI], 8,970-12,997) in the group that continued methotrexate and 22,750 U/mL (95% CI, 19,314-26,796) in the group that suspended methotrexate; the geometric mean ratio was 2.19 (P < .0001; mixed-effects model), reported Abhishek Abhishek, MD, PhD, professor of rheumatology at the University of Nottingham in Nottingham, England, and colleagues.

Prior research showed that stopping methotrexate therapy for 2 weeks following the seasonal influenza vaccine contributed to better vaccine immunity among patients with rheumatoid arthritis, but there was no impact of stopping the drug for up to 4 weeks before vaccination on vaccine-related immunity, the researchers noted.

It is crucial in maximizing long-lasting vaccine protection in people who are possibly susceptible through immune suppression at this point in the COVID-19 vaccination regimen, the study team noted.

“Evidence from this study will be useful for policymakers, national immunization advisory committees, and specialist societies formulating recommendations on the use of methotrexate around the time of COVID-19 vaccination. This evidence will help patients and clinicians make informed choices about the risks and benefits of interrupting methotrexate treatment around the time of COVID-19 vaccination, with implications for the potential to extend such approaches to other therapeutics,” they wrote.

In American College of Rheumatology (ACR) guidance for COVID-19 vaccination, the organization advised against using standard synthetic disease-modifying antirheumatic medicines such as methotrexate “for 1-2 weeks (as disease activity allows) after each COVID-19 vaccine dose,” given the at-risk population and public health concerns, Jeffrey A. Sparks, MD, MMSc, assistant professor of medicine and associate physician at Brigham and Women’s Hospital and Harvard Medical School, Boston, and Sara K. Tedeschi, MD, MPH, assistant professor of medicine at Harvard Medical School, noted in an accompanying editorial in The Lancet: Respiratory Medicine.

However, when the ACR developed this statement, there was only one trial involving patients with rheumatoid arthritis who paused methotrexate following seasonal influenza vaccination, the editorialists said.

Expert commentary

This current study is consistent with other studies over the last several months showing that methotrexate harms both humoral and cell-mediated COVID-19 responses, noted Kevin Winthrop, MD, MPH, professor of infectious disease and public health at Oregon Health & Science University, Portland, who was not involved in the study. “And so now the new wave of studies are like this one, where they are holding methotrexate experimentally and seeing if it makes a difference,” he said.

“The one shortcoming of this study – and so far, the studies to date – is that no one has looked at whether the experimental hold has resulted in a change in T-cell responses, which ... we are [now] recognizing [the importance of] more and more in long-term protection, particularly in severe disease. Theoretically, holding [methotrexate] might help enhance T-cell responses, but that hasn’t been shown experimentally.”

Dr. Winthrop pointed out that one might get the same benefit from holding methotrexate for 1 week instead of 2 and that there likely is a reduced risk of flare-up from underlying autoimmune disease.

It is still not certain that this benefit extends to other vaccines, Dr. Winthrop noted. “It is probably true for most vaccines that if you hold methotrexate for 1 or 2 weeks, you might see some short-term benefit in responsiveness, but you don’t know that there is any clinical meaningfulness of this. That’s going to take other long-term studies. You don’t know how long this benefit lasts.”
 

Pausing methotrexate during initial COVID vaccine doses

Patients with either rheumatoid arthritis or psoriatic arthritis had higher anti-RBD antibody titers when methotrexate was stopped after both doses of the AstraZeneca vaccine, or simply after the second dose, than when methotrexate was continued, according to results from two single-center, randomized controlled trials called MIVAC I and II, Anu Sreekanth, MD, of Sree Sudheendra Medical Mission in Kochi, Kerala, India, and colleagues reported at EULAR 2022.

Results from MIVAC I indicated that there was a higher flare rate when methotrexate was stopped after both vaccine doses, but there was no difference in flare rate in MIVAC II when methotrexate was stopped only after the second dose as opposed to stopping it after both doses.

In the MIVAC I trial, 158 unvaccinated patients were randomized 1:1 to a cohort in which methotrexate was held for 2 weeks after both doses and a cohort in which methotrexate was continued despite the vaccine. In MIVAC II, 157 patients continued methotrexate while receiving the first vaccine dose. These patients were subsequently randomized either to continue or to stop methotrexate for 2 weeks following the second dose.

The findings from MIVAC I demonstrated the flare rate was lower in the methotrexate-continue group than in the methotrexate-pause group (8% vs. 25%; P = .005) and that the median anti-RBD titer was significantly higher for the methotrexate-pause group than the methotrexate-continue group (2,484 vs. 1,147; P = .001).

The results from MIVAC II trial indicated that there was no difference in flare rates between the two study groups (7.9% vs. 11.8%; P = .15). Yet, the median anti-RBD titer was significantly higher in the methotrexate-pause cohort than in the methotrexate-continue cohort (2,553 vs. 990; P = .001).

The report suggests there is a flare risk when methotrexate is stopped, Dr. Sreekanth noted. “It appears more logical to hold only after the second dose, as comparable anti-RBD titers are generated” with either approach, Dr. Sreekanth said.

Expert commentary: MIVAC I and II

Inés Colmegna, MD, associate professor at McGill University in Montreal, noted that it was intriguing that the risk of flares in MIVAC II is half of that reported after each of the doses of MIVAC I. “It is also worth emphasizing that despite the reported frequency of flares, the actual disease activity [as measured by the Disease Activity Score in 28 joints] in patients who did or did not withhold methotrexate was similar.

“MIVAC I and II have practical implications as they help to adequately inform patients about the risk and benefit trade of withholding methotrexate post–COVID-19 vaccination,” Dr. Colmegna told this news organization.

“Additional information would help to [further] interpret the findings of these studies, including whether any of the participants were taking any other DMARDs; data on the severity of the flares and functional impact; analysis of factors that predict the risk of flares, such as higher doses of methotrexate; [and change in] disease activity scores pre- and postvaccination,” Dr. Colmegna concluded.

Dr. Abhishek disclosed relationships with Springer, UpTodate, Oxford, Immunotec, AstraZeneca, Inflazome, NGM Biopharmaceuticals, Menarini Pharmaceuticals, and Cadila Pharmaceuticals. Dr. Abhishek is cochair of the ACR/EULAR CPPD Classification Criteria Working Group and the OMERACT CPPD Working Group. Dr. Sparks disclosed relationships with Gilead, Boehringer Ingelheim, Amgen, Bristol-Myers Squibb, and AbbVie, unrelated to this study. Dr. Tedeschi disclosed relationships with ModernaTx and NGM Biopharmaceuticals. Dr. Winthrop disclosed a research grant and serving as a scientific consultant for Pfizer. Dr. Sreekanth  and Dr. Colmegna have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Patients who take methotrexate for a variety of immune-mediated inflammatory diseases and pause taking the drug following receipt of a COVID-19 vaccine dose did not have a higher risk of disease flare and had higher antireceptor binding domain (anti-RBD) antibody titers and increased immunogenicity when compared with continuing the drug, three recent studies suggest.

In one study, British researchers examined the effects of a 2-week break in methotrexate therapy on anti-RBD titers following receipt of a third COVID-19 vaccine dose. In their paper published in The Lancet: Respiratory Medicine, they reported results from a randomized, open-label, superiority trial that suggested pausing the drug improved immunogenicity, compared with no break.

In two trials presented at the European Alliance of Associations for Rheumatology (EULAR) 2022 Congress, a team from India set out to determine whether holding methotrexate after receiving both doses of a COVID-19 vaccine, or holding it only after the second dose, was safe and effective. They found that pausing methotrexate only following the second dose contributed to a lower flare risk, and that patients had higher anti-RBD titers when holding methotrexate for 2 weeks following each dose.
 

Pausing methotrexate after booster

The 2-week methotrexate break and booster vaccine dose data in the Vaccine Response On Off Methotrexate (VROOM) trial showed that after a month, the geometric mean antispike 1 (S1)-RBD antibody titer was 10,798 U/mL (95% confidence interval [CI], 8,970-12,997) in the group that continued methotrexate and 22,750 U/mL (95% CI, 19,314-26,796) in the group that suspended methotrexate; the geometric mean ratio was 2.19 (P < .0001; mixed-effects model), reported Abhishek Abhishek, MD, PhD, professor of rheumatology at the University of Nottingham in Nottingham, England, and colleagues.

Prior research showed that stopping methotrexate therapy for 2 weeks following the seasonal influenza vaccine contributed to better vaccine immunity among patients with rheumatoid arthritis, but there was no impact of stopping the drug for up to 4 weeks before vaccination on vaccine-related immunity, the researchers noted.

It is crucial in maximizing long-lasting vaccine protection in people who are possibly susceptible through immune suppression at this point in the COVID-19 vaccination regimen, the study team noted.

“Evidence from this study will be useful for policymakers, national immunization advisory committees, and specialist societies formulating recommendations on the use of methotrexate around the time of COVID-19 vaccination. This evidence will help patients and clinicians make informed choices about the risks and benefits of interrupting methotrexate treatment around the time of COVID-19 vaccination, with implications for the potential to extend such approaches to other therapeutics,” they wrote.

In American College of Rheumatology (ACR) guidance for COVID-19 vaccination, the organization advised against using standard synthetic disease-modifying antirheumatic medicines such as methotrexate “for 1-2 weeks (as disease activity allows) after each COVID-19 vaccine dose,” given the at-risk population and public health concerns, Jeffrey A. Sparks, MD, MMSc, assistant professor of medicine and associate physician at Brigham and Women’s Hospital and Harvard Medical School, Boston, and Sara K. Tedeschi, MD, MPH, assistant professor of medicine at Harvard Medical School, noted in an accompanying editorial in The Lancet: Respiratory Medicine.

However, when the ACR developed this statement, there was only one trial involving patients with rheumatoid arthritis who paused methotrexate following seasonal influenza vaccination, the editorialists said.

Expert commentary

This current study is consistent with other studies over the last several months showing that methotrexate harms both humoral and cell-mediated COVID-19 responses, noted Kevin Winthrop, MD, MPH, professor of infectious disease and public health at Oregon Health & Science University, Portland, who was not involved in the study. “And so now the new wave of studies are like this one, where they are holding methotrexate experimentally and seeing if it makes a difference,” he said.

“The one shortcoming of this study – and so far, the studies to date – is that no one has looked at whether the experimental hold has resulted in a change in T-cell responses, which ... we are [now] recognizing [the importance of] more and more in long-term protection, particularly in severe disease. Theoretically, holding [methotrexate] might help enhance T-cell responses, but that hasn’t been shown experimentally.”

Dr. Winthrop pointed out that one might get the same benefit from holding methotrexate for 1 week instead of 2 and that there likely is a reduced risk of flare-up from underlying autoimmune disease.

It is still not certain that this benefit extends to other vaccines, Dr. Winthrop noted. “It is probably true for most vaccines that if you hold methotrexate for 1 or 2 weeks, you might see some short-term benefit in responsiveness, but you don’t know that there is any clinical meaningfulness of this. That’s going to take other long-term studies. You don’t know how long this benefit lasts.”
 

Pausing methotrexate during initial COVID vaccine doses

Patients with either rheumatoid arthritis or psoriatic arthritis had higher anti-RBD antibody titers when methotrexate was stopped after both doses of the AstraZeneca vaccine, or simply after the second dose, than when methotrexate was continued, according to results from two single-center, randomized controlled trials called MIVAC I and II, Anu Sreekanth, MD, of Sree Sudheendra Medical Mission in Kochi, Kerala, India, and colleagues reported at EULAR 2022.

Results from MIVAC I indicated that there was a higher flare rate when methotrexate was stopped after both vaccine doses, but there was no difference in flare rate in MIVAC II when methotrexate was stopped only after the second dose as opposed to stopping it after both doses.

In the MIVAC I trial, 158 unvaccinated patients were randomized 1:1 to a cohort in which methotrexate was held for 2 weeks after both doses and a cohort in which methotrexate was continued despite the vaccine. In MIVAC II, 157 patients continued methotrexate while receiving the first vaccine dose. These patients were subsequently randomized either to continue or to stop methotrexate for 2 weeks following the second dose.

The findings from MIVAC I demonstrated the flare rate was lower in the methotrexate-continue group than in the methotrexate-pause group (8% vs. 25%; P = .005) and that the median anti-RBD titer was significantly higher for the methotrexate-pause group than the methotrexate-continue group (2,484 vs. 1,147; P = .001).

The results from MIVAC II trial indicated that there was no difference in flare rates between the two study groups (7.9% vs. 11.8%; P = .15). Yet, the median anti-RBD titer was significantly higher in the methotrexate-pause cohort than in the methotrexate-continue cohort (2,553 vs. 990; P = .001).

The report suggests there is a flare risk when methotrexate is stopped, Dr. Sreekanth noted. “It appears more logical to hold only after the second dose, as comparable anti-RBD titers are generated” with either approach, Dr. Sreekanth said.

Expert commentary: MIVAC I and II

Inés Colmegna, MD, associate professor at McGill University in Montreal, noted that it was intriguing that the risk of flares in MIVAC II is half of that reported after each of the doses of MIVAC I. “It is also worth emphasizing that despite the reported frequency of flares, the actual disease activity [as measured by the Disease Activity Score in 28 joints] in patients who did or did not withhold methotrexate was similar.

“MIVAC I and II have practical implications as they help to adequately inform patients about the risk and benefit trade of withholding methotrexate post–COVID-19 vaccination,” Dr. Colmegna told this news organization.

“Additional information would help to [further] interpret the findings of these studies, including whether any of the participants were taking any other DMARDs; data on the severity of the flares and functional impact; analysis of factors that predict the risk of flares, such as higher doses of methotrexate; [and change in] disease activity scores pre- and postvaccination,” Dr. Colmegna concluded.

Dr. Abhishek disclosed relationships with Springer, UpTodate, Oxford, Immunotec, AstraZeneca, Inflazome, NGM Biopharmaceuticals, Menarini Pharmaceuticals, and Cadila Pharmaceuticals. Dr. Abhishek is cochair of the ACR/EULAR CPPD Classification Criteria Working Group and the OMERACT CPPD Working Group. Dr. Sparks disclosed relationships with Gilead, Boehringer Ingelheim, Amgen, Bristol-Myers Squibb, and AbbVie, unrelated to this study. Dr. Tedeschi disclosed relationships with ModernaTx and NGM Biopharmaceuticals. Dr. Winthrop disclosed a research grant and serving as a scientific consultant for Pfizer. Dr. Sreekanth  and Dr. Colmegna have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The World Health Organization (WHO) named vaccine hesitancy as one of the top 10 threats to public health as of 2019.¹ Although the COVID-19 vaccines manufactured by Pfizer-BioNTech and Moderna, first authorized for use in November 2020 and fully approved in August 2021,² are widely available in most countries, vaccination uptake is insufficient.³

As of June 2022, 78% of the US population had received at least 1 vaccine dose and 66.8% were fully vaccinated against COVID-19.⁴ High confidence in vaccines is associated with greater uptake; thus, engendering confidence in patients is a critical area of intervention for increasing uptake of COVID-19 and other vaccines.⁵ Despite the steady increase in vaccine acceptance observed following the release of the COVID-19 vaccine, acceptance remains suboptimal.^2,6

Demographic characteristics associated with lower vaccine acceptance include younger age, female sex, lower education and/or income, and Black race or Hispanic/Latinx ethnicity (compared to white or Asian non-­Hispanic).^6,7 Moreover, patients who are skeptical of vaccine safety and efficacy are associated with lower intentions to vaccinate. In contrast, patients with a history of receiving influenza vaccinations and those with a greater concern about COVID-19 and their risk of infection have increased vaccine intentions.⁶

Numerous strategies exist to increase vaccine acceptance; however, there does not appear to be a single “best” method to overcome individual or parental vaccine hesitancy for COVID-19 or other vaccines.^8,9 There are no large-scale randomized controlled trials (RCTs) demonstrating one strategy as more effective than another. In this review, we outline a variety of evidenced-based strategies to help patients overcome vaccine hesitancy for COVID-19 and other vaccines, with a focus on practical tips for primary care physicians (PCPs).

Which talking points are likely to resonate with your patients?

Intervention strategies promote vaccine acceptance by communicating personal benefit, collective benefit, or both to vaccine-­hesitant patients. In a study sample of US undergraduate students, Kim and colleagues¹⁰ found that providing information about the benefits and risks of influenza vaccines resulted in significantly less vaccine intent compared to communicating information only on the benefits. Similarly, Shim and colleagues¹¹ investigated how game theory (acting to maximize personal payoff regardless of payoff to others) and altruism affect influenza vaccination decisions. Through a survey-based study of 427 US university employees, researchers found altruistic motivation had a significant impact on the decision to vaccinate against influenza, resulting in a shift from self-interest to that of the good of the community.¹¹

A German trial on COVID-19 vaccine acceptance by Sprengholz and colleagues¹² found that communications about the benefits of vaccination, availability of financial compensation for vaccination, or a combination of both, did not increase a person’s willingness to get vaccinated. This trial, however, did not separate out individual vs collective benefit, and it was conducted prior to widespread COVID-19 vaccine availability. 

When speaking with patients who are strongly hesitant to vaccination, emphasizing concrete personal benefit may prove more effective than stressing protection of others from illness.

In an online RCT conducted in early 2021, Freeman and colleagues¹³ randomized UK adults to 1 of 10 different “information conditions.” Participants read from 1 of 10 vaccine scripts that varied by the talking points they addressed. The topics that researchers drew from for these scripts included the personal or collective benefit from the COVID-19 vaccine, safety and effectiveness of the vaccine, and the seriousness of the pandemic. They found communications emphasizing personal benefit from vaccination and safety concerns were more effective in participants identified as being strongly hesitant (defined as those who said they would avoid getting the COVID-19 vaccine for as long as possible or who said they’d never get it). However, none of the information arms in this study decreased vaccine hesitancy among those who were doubtful of vaccination (defined as those who said they would delay vaccination or who didn’t know if they would get vaccinated).¹³

Continue to: When encountering patients who are strongly...

When encountering patients who are strongly hesitant to vaccination, an approach emphasizing concrete personal benefit may prove more effective than one stressing protection of others from illness. It is important to note, though, that findings from other countries may not be relevant to US patients due to differences in demographic factors, individual beliefs, and political climate. 

It helps to explain herd immunity by providing concrete examples 

Among the collective benefits of vaccination is the decreased risk of transmitting the disease to others (eg, family, friends, neighbors, colleagues), a quicker “return to normalcy,” and herd immunity.¹³ While individual health benefits may more strongly motivate people to get vaccinated than collective benefits, this may be due to a lack of understanding about herd immunity among the general public. The optimal method of communicating information on herd immunity is not known.¹⁴

Betsch and colleagues¹⁵ found that explaining herd immunity using interactive simulations increased vaccine intent, especially in countries that prioritize the self (rather than prioritizing the group over the individual). In addition to educating study participants about herd immunity, telling them how local vaccine coverage compared to the desired level of coverage helped to increase (influenza) vaccine intent among those who were least informed about herd immunity.¹⁶

Providing concrete examples of the collective benefits of vaccination (eg, protecting grandparents, children too young to be vaccinated, and those at increased risk for severe illness) or sharing stories about how other patients suffered from the disease in question may increase the likelihood of vaccination. One recent trial by Pfattheicher and colleagues¹⁷ found that empathy for those most vulnerable to COVID-19 and increased knowledge about herd immunity were 2 factors associated with greater vaccine intentions.

In this study, the authors induced empathy and increased COVID-19 vaccination intention by having participants read a short story about 2 close siblings who worked together in a nursing facility. In the story, participants learned that both siblings were given a diagnosis of COVID-19 at the same time but only 1 survived.¹⁷

Continue to: Try this 3-pronged approach

Try this 3-pronged approach. Consider explaining herd immunity to vaccine-hesitant patients, pairing this concept with information about local vaccine uptake, and appealing to the patient’s sense of empathy. You might share de-identified information on other patients in your practice or personal network who experienced severe illness, had long-term effects, or died from COVID-19 infection. Such concrete examples may help to increase motivation to vaccinate more than a general appeal to altruism.

Initiate the discussion by emphasizing that community immunity protects those who are vulnerable and lack immunity while providing specific empathetic examples (eg, newborns, cancer survivors) and asking patients to consider friends and family who might be at risk. Additionally, it is essential to explain that although community immunity can decrease the spread of infection, it can only be achieved when enough people are vaccinated. 

Proceed with caution: Addressing conspiracy theories can backfire

Accurate information is critical to improving vaccine intentions; belief in conspiracy theories or misinformation related to COVID-19 is associated with reduced vaccine intentions and uptake.⁶ For example, a study by Loomba and colleagues¹⁸ showed that after exposure to misinformation, US and UK adults reported reduced intentions to vaccinate against COVID-19 once a vaccine became available.

Unfortunately, addressing myths about vaccines can sometimes backfire and unintentionally reinforce vaccine misperceptions.^19,20 This is especially true for patients with the highest levels of concern or mistrust in vaccines. Nyhan and colleagues^21,22 observed the backfire effect in 2 US studies looking at influenza and measles, mumps, and rubella vaccine misperceptions. Although corrective information significantly reduced belief in vaccine myths, they found individuals with the most concerns more strongly endorsed misperceptions when their beliefs were challenged.^21,22

Strategies for correcting vaccine misinformation may vary by type of vaccine; however, placing emphasis on facts delivered by trusted sources appears to be beneficial.

An Australian randomized study by Steffens and colleagues²³ found repeating myths about childhood vaccines, followed by corrective text, to parents of children ages 0 to 5 years had no difference on parental intent to vaccinate their children compared to providing vaccine information as a statement or in a question/answer format. Furthermore, an RCT in Brazil by Carey and colleagues²⁴ found that myth-correction messages about Zika virus failed to reduce misperceptions about the virus and actually reduced the belief in factual information about Zika—­regardless of baseline beliefs in conspiracies. However, a similar experiment in the same study showed that myth-correction messages reduced false beliefs about yellow fever.

Continue to: The authors speculated...

The authors speculated that this may be because Zika is a relatively new virus when compared to yellow fever, and participants may have more pre-existing knowledge about yellow fever.²⁴ These findings are important to keep in mind when addressing misinformation regarding COVID-19. When addressing myth perceptions with patients, consider pivoting the conversation from vaccine myths to the disease itself, focusing on the disease risk and severity of symptoms.^19,20 

Other studies have had positive results when addressing misinformation, including a digital RCT of older adults in the Netherlands by Yousuf and colleagues.²⁵ In this study, participants were randomized to view 1 of 2 versions of an information video on vaccination featuring an informative discussion by celebrity scientists, government officials, and a cardiologist. Video 1 did not include debunking strategies, only information about vaccination; Video 2 provided the same information about vaccines but also described the myths surrounding vaccines and reiterated the truth to debunk the myths.

Findings demonstrated that a significantly higher number of participants in the Video 2 group overcame vaccination myths related to influenza and COVID-19.²⁵ Notably, this study took place prior to the widespread availability of COVID-19 vaccines and did not measure intent to vaccinate against COVID-19.

Taken together, strategies for correcting vaccine misinformation may vary by population as well as type of vaccine; however, placing emphasis on facts delivered by trusted sources appears to be beneficial. When addressing misinformation, PCPs should first focus on key details (not all supporting information) and clearly explain why the misinformation is false before pointing out the actual myth and providing an alternative explanation.²⁰ When caring for patients who express strong concerns over the vaccine in question or have avid beliefs in certain myths or conspiracy theories, it’s best to pivot the conversation back to the disease rather than address the misinformation to avoid a potential backfire effect.

Utilize these effective communication techniques

TABLE 1^{10,13,16,17,19,20} summarizes the “do’s and don’ts” of communicating with vaccine-hesitant patients. PCPs should provide strong recommendations for vaccination, approaching it presumptively—ie, framing it as normative behavior.^19,26 This approach is critical to building patient trust so that vaccine-hesitant patients feel the PCP is truly listening to them and addressing their concerns.²⁷ Additionally, implementing motivational interviewing (MI) and self-determination theory (SDT)²⁸ techniques when discussing vaccinations with patients can improve intentions and uptake.^19,29TABLE 2^19,29 outlines specific techniques based on SDT and MI that PCPs may utilize to communicate with vaccine-hesitant individuals or parents. 

Continue to: The takeaway

Strategies for increasing vaccine intentions include educating hesitant patients about the benefits and risks of vaccines, addressing misinformation, and explaining the personal and collective benefits of vaccination. These strategies appear to be more effective when delivered by a trusted source, such as a health care provider (HCP). Care should be taken when implementing vaccine-acceptance strategies to ensure that they are tailored to specific populations and vaccines.

At this stage in the COVID-19 pandemic, when several vaccines have been widely available for more than a year, we expect that the majority of patients desiring vaccination (ie, those with the greatest vaccine intent) have already received them. With the recent approval of COVID-19 vaccines for children younger than 5 years, we must now advocate for our patients to vaccinate not only themselves, but their children. Patients who remain unvaccinated may be hesitant or outright reject vaccination for a number of reasons, including fear or skepticism over the safety and efficacy of the vaccine, belief in conspiracy theories, belief that COVID-19 is not real or not severe, or mistrust of the government.⁶ Vaccine hesitation or rejection is also often political in nature.

Based on the studies included in this review, we have identified several strategies for reducing vaccine hesitancy, which can be used with vaccine-hesitant patients and parents. We suggest emphasizing the personal benefit of vaccination and focusing on specific disease risks. If time allows, you can also explain the collective benefit of vaccination through herd immunity, including the current levels of local vaccine uptake compared to the desired level for community immunity. Communicating the collective benefits of vaccination may be more effective when paired with a strategy intended to increase empathy and altruism, such as sharing actual stories about those who have suffered from a vaccine-preventable disease.

Build trust by asking your patient: What kind of information do you feel you are missing about the vaccine?

Addressing myths and misinformation related to COVID-19 and other vaccines, with emphasis placed on the correct information delivered by trusted sources may be beneficial for those who are uncertain but not strongly against vaccination. For those who remain staunchly hesitant against vaccination, we recommend focusing on the personal benefits of vaccination with a focus on delivering facts about the risk of the disease in question, rather than trying to refute misinformation.

COVID-19 vaccine acceptance in the United States is disturbingly low among health care workers, particularly nurses, technicians, and those in nonclinical roles, compared to physicians.^6,30 Many of the strategies for addressing vaccine hesitancy among the general population can also apply to health care personnel (eg, vaccine education, addressing misinformation, delivering information from a trusted source). Health care personnel may also be subject to vaccine mandates by their employers, which have demonstrated increases in vaccination rates for influenza.³¹ Given that COVID-19 vaccination recommendations made by HCPs are associated with greater vaccine intentions and uptake,⁶ reducing hesitancy among health care workers is a critical first step to achieving optimal implementation.

CORRESPONDENCE
Nicole Mayo, PhD, 236 Pearl Street, Rochester, NY 14607; Nicole_Mayo@URMC.Rochester.edu

The World Health Organization (WHO) named vaccine hesitancy as one of the top 10 threats to public health as of 2019.¹ Although the COVID-19 vaccines manufactured by Pfizer-BioNTech and Moderna, first authorized for use in November 2020 and fully approved in August 2021,² are widely available in most countries, vaccination uptake is insufficient.³

As of June 2022, 78% of the US population had received at least 1 vaccine dose and 66.8% were fully vaccinated against COVID-19.⁴ High confidence in vaccines is associated with greater uptake; thus, engendering confidence in patients is a critical area of intervention for increasing uptake of COVID-19 and other vaccines.⁵ Despite the steady increase in vaccine acceptance observed following the release of the COVID-19 vaccine, acceptance remains suboptimal.^2,6

Demographic characteristics associated with lower vaccine acceptance include younger age, female sex, lower education and/or income, and Black race or Hispanic/Latinx ethnicity (compared to white or Asian non-­Hispanic).^6,7 Moreover, patients who are skeptical of vaccine safety and efficacy are associated with lower intentions to vaccinate. In contrast, patients with a history of receiving influenza vaccinations and those with a greater concern about COVID-19 and their risk of infection have increased vaccine intentions.⁶

Numerous strategies exist to increase vaccine acceptance; however, there does not appear to be a single “best” method to overcome individual or parental vaccine hesitancy for COVID-19 or other vaccines.^8,9 There are no large-scale randomized controlled trials (RCTs) demonstrating one strategy as more effective than another. In this review, we outline a variety of evidenced-based strategies to help patients overcome vaccine hesitancy for COVID-19 and other vaccines, with a focus on practical tips for primary care physicians (PCPs).

Which talking points are likely to resonate with your patients?

Intervention strategies promote vaccine acceptance by communicating personal benefit, collective benefit, or both to vaccine-­hesitant patients. In a study sample of US undergraduate students, Kim and colleagues¹⁰ found that providing information about the benefits and risks of influenza vaccines resulted in significantly less vaccine intent compared to communicating information only on the benefits. Similarly, Shim and colleagues¹¹ investigated how game theory (acting to maximize personal payoff regardless of payoff to others) and altruism affect influenza vaccination decisions. Through a survey-based study of 427 US university employees, researchers found altruistic motivation had a significant impact on the decision to vaccinate against influenza, resulting in a shift from self-interest to that of the good of the community.¹¹

A German trial on COVID-19 vaccine acceptance by Sprengholz and colleagues¹² found that communications about the benefits of vaccination, availability of financial compensation for vaccination, or a combination of both, did not increase a person’s willingness to get vaccinated. This trial, however, did not separate out individual vs collective benefit, and it was conducted prior to widespread COVID-19 vaccine availability. 

When speaking with patients who are strongly hesitant to vaccination, emphasizing concrete personal benefit may prove more effective than stressing protection of others from illness.

In an online RCT conducted in early 2021, Freeman and colleagues¹³ randomized UK adults to 1 of 10 different “information conditions.” Participants read from 1 of 10 vaccine scripts that varied by the talking points they addressed. The topics that researchers drew from for these scripts included the personal or collective benefit from the COVID-19 vaccine, safety and effectiveness of the vaccine, and the seriousness of the pandemic. They found communications emphasizing personal benefit from vaccination and safety concerns were more effective in participants identified as being strongly hesitant (defined as those who said they would avoid getting the COVID-19 vaccine for as long as possible or who said they’d never get it). However, none of the information arms in this study decreased vaccine hesitancy among those who were doubtful of vaccination (defined as those who said they would delay vaccination or who didn’t know if they would get vaccinated).¹³

Continue to: When encountering patients who are strongly...

When encountering patients who are strongly hesitant to vaccination, an approach emphasizing concrete personal benefit may prove more effective than one stressing protection of others from illness. It is important to note, though, that findings from other countries may not be relevant to US patients due to differences in demographic factors, individual beliefs, and political climate. 

It helps to explain herd immunity by providing concrete examples 

Among the collective benefits of vaccination is the decreased risk of transmitting the disease to others (eg, family, friends, neighbors, colleagues), a quicker “return to normalcy,” and herd immunity.¹³ While individual health benefits may more strongly motivate people to get vaccinated than collective benefits, this may be due to a lack of understanding about herd immunity among the general public. The optimal method of communicating information on herd immunity is not known.¹⁴

Betsch and colleagues¹⁵ found that explaining herd immunity using interactive simulations increased vaccine intent, especially in countries that prioritize the self (rather than prioritizing the group over the individual). In addition to educating study participants about herd immunity, telling them how local vaccine coverage compared to the desired level of coverage helped to increase (influenza) vaccine intent among those who were least informed about herd immunity.¹⁶

Providing concrete examples of the collective benefits of vaccination (eg, protecting grandparents, children too young to be vaccinated, and those at increased risk for severe illness) or sharing stories about how other patients suffered from the disease in question may increase the likelihood of vaccination. One recent trial by Pfattheicher and colleagues¹⁷ found that empathy for those most vulnerable to COVID-19 and increased knowledge about herd immunity were 2 factors associated with greater vaccine intentions.

In this study, the authors induced empathy and increased COVID-19 vaccination intention by having participants read a short story about 2 close siblings who worked together in a nursing facility. In the story, participants learned that both siblings were given a diagnosis of COVID-19 at the same time but only 1 survived.¹⁷

Continue to: Try this 3-pronged approach

Try this 3-pronged approach. Consider explaining herd immunity to vaccine-hesitant patients, pairing this concept with information about local vaccine uptake, and appealing to the patient’s sense of empathy. You might share de-identified information on other patients in your practice or personal network who experienced severe illness, had long-term effects, or died from COVID-19 infection. Such concrete examples may help to increase motivation to vaccinate more than a general appeal to altruism.

Initiate the discussion by emphasizing that community immunity protects those who are vulnerable and lack immunity while providing specific empathetic examples (eg, newborns, cancer survivors) and asking patients to consider friends and family who might be at risk. Additionally, it is essential to explain that although community immunity can decrease the spread of infection, it can only be achieved when enough people are vaccinated. 

Proceed with caution: Addressing conspiracy theories can backfire

Accurate information is critical to improving vaccine intentions; belief in conspiracy theories or misinformation related to COVID-19 is associated with reduced vaccine intentions and uptake.⁶ For example, a study by Loomba and colleagues¹⁸ showed that after exposure to misinformation, US and UK adults reported reduced intentions to vaccinate against COVID-19 once a vaccine became available.

Unfortunately, addressing myths about vaccines can sometimes backfire and unintentionally reinforce vaccine misperceptions.^19,20 This is especially true for patients with the highest levels of concern or mistrust in vaccines. Nyhan and colleagues^21,22 observed the backfire effect in 2 US studies looking at influenza and measles, mumps, and rubella vaccine misperceptions. Although corrective information significantly reduced belief in vaccine myths, they found individuals with the most concerns more strongly endorsed misperceptions when their beliefs were challenged.^21,22

Strategies for correcting vaccine misinformation may vary by type of vaccine; however, placing emphasis on facts delivered by trusted sources appears to be beneficial.

An Australian randomized study by Steffens and colleagues²³ found repeating myths about childhood vaccines, followed by corrective text, to parents of children ages 0 to 5 years had no difference on parental intent to vaccinate their children compared to providing vaccine information as a statement or in a question/answer format. Furthermore, an RCT in Brazil by Carey and colleagues²⁴ found that myth-correction messages about Zika virus failed to reduce misperceptions about the virus and actually reduced the belief in factual information about Zika—­regardless of baseline beliefs in conspiracies. However, a similar experiment in the same study showed that myth-correction messages reduced false beliefs about yellow fever.

Continue to: The authors speculated...

The authors speculated that this may be because Zika is a relatively new virus when compared to yellow fever, and participants may have more pre-existing knowledge about yellow fever.²⁴ These findings are important to keep in mind when addressing misinformation regarding COVID-19. When addressing myth perceptions with patients, consider pivoting the conversation from vaccine myths to the disease itself, focusing on the disease risk and severity of symptoms.^19,20 

Other studies have had positive results when addressing misinformation, including a digital RCT of older adults in the Netherlands by Yousuf and colleagues.²⁵ In this study, participants were randomized to view 1 of 2 versions of an information video on vaccination featuring an informative discussion by celebrity scientists, government officials, and a cardiologist. Video 1 did not include debunking strategies, only information about vaccination; Video 2 provided the same information about vaccines but also described the myths surrounding vaccines and reiterated the truth to debunk the myths.

Findings demonstrated that a significantly higher number of participants in the Video 2 group overcame vaccination myths related to influenza and COVID-19.²⁵ Notably, this study took place prior to the widespread availability of COVID-19 vaccines and did not measure intent to vaccinate against COVID-19.

Taken together, strategies for correcting vaccine misinformation may vary by population as well as type of vaccine; however, placing emphasis on facts delivered by trusted sources appears to be beneficial. When addressing misinformation, PCPs should first focus on key details (not all supporting information) and clearly explain why the misinformation is false before pointing out the actual myth and providing an alternative explanation.²⁰ When caring for patients who express strong concerns over the vaccine in question or have avid beliefs in certain myths or conspiracy theories, it’s best to pivot the conversation back to the disease rather than address the misinformation to avoid a potential backfire effect.

Utilize these effective communication techniques

TABLE 1^{10,13,16,17,19,20} summarizes the “do’s and don’ts” of communicating with vaccine-hesitant patients. PCPs should provide strong recommendations for vaccination, approaching it presumptively—ie, framing it as normative behavior.^19,26 This approach is critical to building patient trust so that vaccine-hesitant patients feel the PCP is truly listening to them and addressing their concerns.²⁷ Additionally, implementing motivational interviewing (MI) and self-determination theory (SDT)²⁸ techniques when discussing vaccinations with patients can improve intentions and uptake.^19,29TABLE 2^19,29 outlines specific techniques based on SDT and MI that PCPs may utilize to communicate with vaccine-hesitant individuals or parents. 

Continue to: The takeaway

Strategies for increasing vaccine intentions include educating hesitant patients about the benefits and risks of vaccines, addressing misinformation, and explaining the personal and collective benefits of vaccination. These strategies appear to be more effective when delivered by a trusted source, such as a health care provider (HCP). Care should be taken when implementing vaccine-acceptance strategies to ensure that they are tailored to specific populations and vaccines.

At this stage in the COVID-19 pandemic, when several vaccines have been widely available for more than a year, we expect that the majority of patients desiring vaccination (ie, those with the greatest vaccine intent) have already received them. With the recent approval of COVID-19 vaccines for children younger than 5 years, we must now advocate for our patients to vaccinate not only themselves, but their children. Patients who remain unvaccinated may be hesitant or outright reject vaccination for a number of reasons, including fear or skepticism over the safety and efficacy of the vaccine, belief in conspiracy theories, belief that COVID-19 is not real or not severe, or mistrust of the government.⁶ Vaccine hesitation or rejection is also often political in nature.

Based on the studies included in this review, we have identified several strategies for reducing vaccine hesitancy, which can be used with vaccine-hesitant patients and parents. We suggest emphasizing the personal benefit of vaccination and focusing on specific disease risks. If time allows, you can also explain the collective benefit of vaccination through herd immunity, including the current levels of local vaccine uptake compared to the desired level for community immunity. Communicating the collective benefits of vaccination may be more effective when paired with a strategy intended to increase empathy and altruism, such as sharing actual stories about those who have suffered from a vaccine-preventable disease.

Build trust by asking your patient: What kind of information do you feel you are missing about the vaccine?

Addressing myths and misinformation related to COVID-19 and other vaccines, with emphasis placed on the correct information delivered by trusted sources may be beneficial for those who are uncertain but not strongly against vaccination. For those who remain staunchly hesitant against vaccination, we recommend focusing on the personal benefits of vaccination with a focus on delivering facts about the risk of the disease in question, rather than trying to refute misinformation.

COVID-19 vaccine acceptance in the United States is disturbingly low among health care workers, particularly nurses, technicians, and those in nonclinical roles, compared to physicians.^6,30 Many of the strategies for addressing vaccine hesitancy among the general population can also apply to health care personnel (eg, vaccine education, addressing misinformation, delivering information from a trusted source). Health care personnel may also be subject to vaccine mandates by their employers, which have demonstrated increases in vaccination rates for influenza.³¹ Given that COVID-19 vaccination recommendations made by HCPs are associated with greater vaccine intentions and uptake,⁶ reducing hesitancy among health care workers is a critical first step to achieving optimal implementation.

CORRESPONDENCE
Nicole Mayo, PhD, 236 Pearl Street, Rochester, NY 14607; Nicole_Mayo@URMC.Rochester.edu

The World Health Organization (WHO) named vaccine hesitancy as one of the top 10 threats to public health as of 2019.¹ Although the COVID-19 vaccines manufactured by Pfizer-BioNTech and Moderna, first authorized for use in November 2020 and fully approved in August 2021,² are widely available in most countries, vaccination uptake is insufficient.³

As of June 2022, 78% of the US population had received at least 1 vaccine dose and 66.8% were fully vaccinated against COVID-19.⁴ High confidence in vaccines is associated with greater uptake; thus, engendering confidence in patients is a critical area of intervention for increasing uptake of COVID-19 and other vaccines.⁵ Despite the steady increase in vaccine acceptance observed following the release of the COVID-19 vaccine, acceptance remains suboptimal.^2,6

Demographic characteristics associated with lower vaccine acceptance include younger age, female sex, lower education and/or income, and Black race or Hispanic/Latinx ethnicity (compared to white or Asian non-­Hispanic).^6,7 Moreover, patients who are skeptical of vaccine safety and efficacy are associated with lower intentions to vaccinate. In contrast, patients with a history of receiving influenza vaccinations and those with a greater concern about COVID-19 and their risk of infection have increased vaccine intentions.⁶

Numerous strategies exist to increase vaccine acceptance; however, there does not appear to be a single “best” method to overcome individual or parental vaccine hesitancy for COVID-19 or other vaccines.^8,9 There are no large-scale randomized controlled trials (RCTs) demonstrating one strategy as more effective than another. In this review, we outline a variety of evidenced-based strategies to help patients overcome vaccine hesitancy for COVID-19 and other vaccines, with a focus on practical tips for primary care physicians (PCPs).

Which talking points are likely to resonate with your patients?

Intervention strategies promote vaccine acceptance by communicating personal benefit, collective benefit, or both to vaccine-­hesitant patients. In a study sample of US undergraduate students, Kim and colleagues¹⁰ found that providing information about the benefits and risks of influenza vaccines resulted in significantly less vaccine intent compared to communicating information only on the benefits. Similarly, Shim and colleagues¹¹ investigated how game theory (acting to maximize personal payoff regardless of payoff to others) and altruism affect influenza vaccination decisions. Through a survey-based study of 427 US university employees, researchers found altruistic motivation had a significant impact on the decision to vaccinate against influenza, resulting in a shift from self-interest to that of the good of the community.¹¹

A German trial on COVID-19 vaccine acceptance by Sprengholz and colleagues¹² found that communications about the benefits of vaccination, availability of financial compensation for vaccination, or a combination of both, did not increase a person’s willingness to get vaccinated. This trial, however, did not separate out individual vs collective benefit, and it was conducted prior to widespread COVID-19 vaccine availability. 

When speaking with patients who are strongly hesitant to vaccination, emphasizing concrete personal benefit may prove more effective than stressing protection of others from illness.

In an online RCT conducted in early 2021, Freeman and colleagues¹³ randomized UK adults to 1 of 10 different “information conditions.” Participants read from 1 of 10 vaccine scripts that varied by the talking points they addressed. The topics that researchers drew from for these scripts included the personal or collective benefit from the COVID-19 vaccine, safety and effectiveness of the vaccine, and the seriousness of the pandemic. They found communications emphasizing personal benefit from vaccination and safety concerns were more effective in participants identified as being strongly hesitant (defined as those who said they would avoid getting the COVID-19 vaccine for as long as possible or who said they’d never get it). However, none of the information arms in this study decreased vaccine hesitancy among those who were doubtful of vaccination (defined as those who said they would delay vaccination or who didn’t know if they would get vaccinated).¹³

Continue to: When encountering patients who are strongly...

When encountering patients who are strongly hesitant to vaccination, an approach emphasizing concrete personal benefit may prove more effective than one stressing protection of others from illness. It is important to note, though, that findings from other countries may not be relevant to US patients due to differences in demographic factors, individual beliefs, and political climate. 

It helps to explain herd immunity by providing concrete examples 

Among the collective benefits of vaccination is the decreased risk of transmitting the disease to others (eg, family, friends, neighbors, colleagues), a quicker “return to normalcy,” and herd immunity.¹³ While individual health benefits may more strongly motivate people to get vaccinated than collective benefits, this may be due to a lack of understanding about herd immunity among the general public. The optimal method of communicating information on herd immunity is not known.¹⁴

Betsch and colleagues¹⁵ found that explaining herd immunity using interactive simulations increased vaccine intent, especially in countries that prioritize the self (rather than prioritizing the group over the individual). In addition to educating study participants about herd immunity, telling them how local vaccine coverage compared to the desired level of coverage helped to increase (influenza) vaccine intent among those who were least informed about herd immunity.¹⁶

Providing concrete examples of the collective benefits of vaccination (eg, protecting grandparents, children too young to be vaccinated, and those at increased risk for severe illness) or sharing stories about how other patients suffered from the disease in question may increase the likelihood of vaccination. One recent trial by Pfattheicher and colleagues¹⁷ found that empathy for those most vulnerable to COVID-19 and increased knowledge about herd immunity were 2 factors associated with greater vaccine intentions.

In this study, the authors induced empathy and increased COVID-19 vaccination intention by having participants read a short story about 2 close siblings who worked together in a nursing facility. In the story, participants learned that both siblings were given a diagnosis of COVID-19 at the same time but only 1 survived.¹⁷

Continue to: Try this 3-pronged approach

Try this 3-pronged approach. Consider explaining herd immunity to vaccine-hesitant patients, pairing this concept with information about local vaccine uptake, and appealing to the patient’s sense of empathy. You might share de-identified information on other patients in your practice or personal network who experienced severe illness, had long-term effects, or died from COVID-19 infection. Such concrete examples may help to increase motivation to vaccinate more than a general appeal to altruism.

Initiate the discussion by emphasizing that community immunity protects those who are vulnerable and lack immunity while providing specific empathetic examples (eg, newborns, cancer survivors) and asking patients to consider friends and family who might be at risk. Additionally, it is essential to explain that although community immunity can decrease the spread of infection, it can only be achieved when enough people are vaccinated. 

Proceed with caution: Addressing conspiracy theories can backfire

Accurate information is critical to improving vaccine intentions; belief in conspiracy theories or misinformation related to COVID-19 is associated with reduced vaccine intentions and uptake.⁶ For example, a study by Loomba and colleagues¹⁸ showed that after exposure to misinformation, US and UK adults reported reduced intentions to vaccinate against COVID-19 once a vaccine became available.

Unfortunately, addressing myths about vaccines can sometimes backfire and unintentionally reinforce vaccine misperceptions.^19,20 This is especially true for patients with the highest levels of concern or mistrust in vaccines. Nyhan and colleagues^21,22 observed the backfire effect in 2 US studies looking at influenza and measles, mumps, and rubella vaccine misperceptions. Although corrective information significantly reduced belief in vaccine myths, they found individuals with the most concerns more strongly endorsed misperceptions when their beliefs were challenged.^21,22

Strategies for correcting vaccine misinformation may vary by type of vaccine; however, placing emphasis on facts delivered by trusted sources appears to be beneficial.

An Australian randomized study by Steffens and colleagues²³ found repeating myths about childhood vaccines, followed by corrective text, to parents of children ages 0 to 5 years had no difference on parental intent to vaccinate their children compared to providing vaccine information as a statement or in a question/answer format. Furthermore, an RCT in Brazil by Carey and colleagues²⁴ found that myth-correction messages about Zika virus failed to reduce misperceptions about the virus and actually reduced the belief in factual information about Zika—­regardless of baseline beliefs in conspiracies. However, a similar experiment in the same study showed that myth-correction messages reduced false beliefs about yellow fever.

Continue to: The authors speculated...

The authors speculated that this may be because Zika is a relatively new virus when compared to yellow fever, and participants may have more pre-existing knowledge about yellow fever.²⁴ These findings are important to keep in mind when addressing misinformation regarding COVID-19. When addressing myth perceptions with patients, consider pivoting the conversation from vaccine myths to the disease itself, focusing on the disease risk and severity of symptoms.^19,20 

Other studies have had positive results when addressing misinformation, including a digital RCT of older adults in the Netherlands by Yousuf and colleagues.²⁵ In this study, participants were randomized to view 1 of 2 versions of an information video on vaccination featuring an informative discussion by celebrity scientists, government officials, and a cardiologist. Video 1 did not include debunking strategies, only information about vaccination; Video 2 provided the same information about vaccines but also described the myths surrounding vaccines and reiterated the truth to debunk the myths.

Findings demonstrated that a significantly higher number of participants in the Video 2 group overcame vaccination myths related to influenza and COVID-19.²⁵ Notably, this study took place prior to the widespread availability of COVID-19 vaccines and did not measure intent to vaccinate against COVID-19.

Taken together, strategies for correcting vaccine misinformation may vary by population as well as type of vaccine; however, placing emphasis on facts delivered by trusted sources appears to be beneficial. When addressing misinformation, PCPs should first focus on key details (not all supporting information) and clearly explain why the misinformation is false before pointing out the actual myth and providing an alternative explanation.²⁰ When caring for patients who express strong concerns over the vaccine in question or have avid beliefs in certain myths or conspiracy theories, it’s best to pivot the conversation back to the disease rather than address the misinformation to avoid a potential backfire effect.

Utilize these effective communication techniques

TABLE 1^{10,13,16,17,19,20} summarizes the “do’s and don’ts” of communicating with vaccine-hesitant patients. PCPs should provide strong recommendations for vaccination, approaching it presumptively—ie, framing it as normative behavior.^19,26 This approach is critical to building patient trust so that vaccine-hesitant patients feel the PCP is truly listening to them and addressing their concerns.²⁷ Additionally, implementing motivational interviewing (MI) and self-determination theory (SDT)²⁸ techniques when discussing vaccinations with patients can improve intentions and uptake.^19,29TABLE 2^19,29 outlines specific techniques based on SDT and MI that PCPs may utilize to communicate with vaccine-hesitant individuals or parents. 

Continue to: The takeaway

Strategies for increasing vaccine intentions include educating hesitant patients about the benefits and risks of vaccines, addressing misinformation, and explaining the personal and collective benefits of vaccination. These strategies appear to be more effective when delivered by a trusted source, such as a health care provider (HCP). Care should be taken when implementing vaccine-acceptance strategies to ensure that they are tailored to specific populations and vaccines.

At this stage in the COVID-19 pandemic, when several vaccines have been widely available for more than a year, we expect that the majority of patients desiring vaccination (ie, those with the greatest vaccine intent) have already received them. With the recent approval of COVID-19 vaccines for children younger than 5 years, we must now advocate for our patients to vaccinate not only themselves, but their children. Patients who remain unvaccinated may be hesitant or outright reject vaccination for a number of reasons, including fear or skepticism over the safety and efficacy of the vaccine, belief in conspiracy theories, belief that COVID-19 is not real or not severe, or mistrust of the government.⁶ Vaccine hesitation or rejection is also often political in nature.

Based on the studies included in this review, we have identified several strategies for reducing vaccine hesitancy, which can be used with vaccine-hesitant patients and parents. We suggest emphasizing the personal benefit of vaccination and focusing on specific disease risks. If time allows, you can also explain the collective benefit of vaccination through herd immunity, including the current levels of local vaccine uptake compared to the desired level for community immunity. Communicating the collective benefits of vaccination may be more effective when paired with a strategy intended to increase empathy and altruism, such as sharing actual stories about those who have suffered from a vaccine-preventable disease.

Build trust by asking your patient: What kind of information do you feel you are missing about the vaccine?

Addressing myths and misinformation related to COVID-19 and other vaccines, with emphasis placed on the correct information delivered by trusted sources may be beneficial for those who are uncertain but not strongly against vaccination. For those who remain staunchly hesitant against vaccination, we recommend focusing on the personal benefits of vaccination with a focus on delivering facts about the risk of the disease in question, rather than trying to refute misinformation.

COVID-19 vaccine acceptance in the United States is disturbingly low among health care workers, particularly nurses, technicians, and those in nonclinical roles, compared to physicians.^6,30 Many of the strategies for addressing vaccine hesitancy among the general population can also apply to health care personnel (eg, vaccine education, addressing misinformation, delivering information from a trusted source). Health care personnel may also be subject to vaccine mandates by their employers, which have demonstrated increases in vaccination rates for influenza.³¹ Given that COVID-19 vaccination recommendations made by HCPs are associated with greater vaccine intentions and uptake,⁶ reducing hesitancy among health care workers is a critical first step to achieving optimal implementation.

CORRESPONDENCE
Nicole Mayo, PhD, 236 Pearl Street, Rochester, NY 14607; Nicole_Mayo@URMC.Rochester.edu

Amazon is working with the Fred Hutchinson Cancer Research Center to develop cancer vaccines in a new clinical trial.

The trial is aimed at finding “personalized vaccines” to treat breast cancer and melanoma. The phase 1 trial is recruiting 20 people over the age of 18 to study the safety of the vaccines, according to CNBC.

The Fred Hutchinson Cancer Research Center and University of Washington Cancer Consortium are listed as the researchers of the clinical trial, and Amazon is listed as a collaborator, according to a filing on the ClinicalTrials.gov database.

“Amazon is contributing scientific and machine learning expertise to a partnership with Fred Hutch to explore the development of a personalized treatment for certain forms of cancer,” an Amazon spokesperson told CNBC.

“It’s very early, but Fred Hutch recently received permission from the U.S. Food and Drug Administration to proceed with a phase 1 clinical trial, and it’s unclear whether it will be successful,” the spokesperson said. “This will be a long, multiyear process – should it progress, we would be open to working with other organizations in health care and life sciences that might also be interested in similar efforts.”

In recent years, Amazon has grown its presence in the health care industry, CNBC reported. The company launched an online pharmacy in 2020, developed a telehealth service called Amazon Care, and released its own COVID-19 test during the pandemic.

A research and development group inside Amazon, known as Grand Challenge, oversaw the company’s early cancer vaccine effort, according to Business Insider. It’s now under the purview of a cancer research team that reports to Robert Williams, the company’s vice president of devices.

The study was first posted on ClinicalTrials.gov in October 2021 and began recruiting patients on June 9, according to the filing. The phase 1 trial is expected to run through November 2023.

The phase 1 trial will study the safety of personalized vaccines to treat patients with late-stage melanoma or hormone receptor-positive HER2-negative breast cancer which has either spread to other parts of the body or doesn’t respond to treatment.

More information about the study can be found on ClinicalTrials.gov under the identifier NCT05098210.

A version of this article first appeared on WebMD.com.

Amazon is working with the Fred Hutchinson Cancer Research Center to develop cancer vaccines in a new clinical trial.

The trial is aimed at finding “personalized vaccines” to treat breast cancer and melanoma. The phase 1 trial is recruiting 20 people over the age of 18 to study the safety of the vaccines, according to CNBC.

The Fred Hutchinson Cancer Research Center and University of Washington Cancer Consortium are listed as the researchers of the clinical trial, and Amazon is listed as a collaborator, according to a filing on the ClinicalTrials.gov database.

“Amazon is contributing scientific and machine learning expertise to a partnership with Fred Hutch to explore the development of a personalized treatment for certain forms of cancer,” an Amazon spokesperson told CNBC.

“It’s very early, but Fred Hutch recently received permission from the U.S. Food and Drug Administration to proceed with a phase 1 clinical trial, and it’s unclear whether it will be successful,” the spokesperson said. “This will be a long, multiyear process – should it progress, we would be open to working with other organizations in health care and life sciences that might also be interested in similar efforts.”

In recent years, Amazon has grown its presence in the health care industry, CNBC reported. The company launched an online pharmacy in 2020, developed a telehealth service called Amazon Care, and released its own COVID-19 test during the pandemic.

A research and development group inside Amazon, known as Grand Challenge, oversaw the company’s early cancer vaccine effort, according to Business Insider. It’s now under the purview of a cancer research team that reports to Robert Williams, the company’s vice president of devices.

The study was first posted on ClinicalTrials.gov in October 2021 and began recruiting patients on June 9, according to the filing. The phase 1 trial is expected to run through November 2023.

The phase 1 trial will study the safety of personalized vaccines to treat patients with late-stage melanoma or hormone receptor-positive HER2-negative breast cancer which has either spread to other parts of the body or doesn’t respond to treatment.

More information about the study can be found on ClinicalTrials.gov under the identifier NCT05098210.

A version of this article first appeared on WebMD.com.

Amazon is working with the Fred Hutchinson Cancer Research Center to develop cancer vaccines in a new clinical trial.

The trial is aimed at finding “personalized vaccines” to treat breast cancer and melanoma. The phase 1 trial is recruiting 20 people over the age of 18 to study the safety of the vaccines, according to CNBC.

The Fred Hutchinson Cancer Research Center and University of Washington Cancer Consortium are listed as the researchers of the clinical trial, and Amazon is listed as a collaborator, according to a filing on the ClinicalTrials.gov database.

“Amazon is contributing scientific and machine learning expertise to a partnership with Fred Hutch to explore the development of a personalized treatment for certain forms of cancer,” an Amazon spokesperson told CNBC.

“It’s very early, but Fred Hutch recently received permission from the U.S. Food and Drug Administration to proceed with a phase 1 clinical trial, and it’s unclear whether it will be successful,” the spokesperson said. “This will be a long, multiyear process – should it progress, we would be open to working with other organizations in health care and life sciences that might also be interested in similar efforts.”

In recent years, Amazon has grown its presence in the health care industry, CNBC reported. The company launched an online pharmacy in 2020, developed a telehealth service called Amazon Care, and released its own COVID-19 test during the pandemic.

A research and development group inside Amazon, known as Grand Challenge, oversaw the company’s early cancer vaccine effort, according to Business Insider. It’s now under the purview of a cancer research team that reports to Robert Williams, the company’s vice president of devices.

The study was first posted on ClinicalTrials.gov in October 2021 and began recruiting patients on June 9, according to the filing. The phase 1 trial is expected to run through November 2023.

The phase 1 trial will study the safety of personalized vaccines to treat patients with late-stage melanoma or hormone receptor-positive HER2-negative breast cancer which has either spread to other parts of the body or doesn’t respond to treatment.

More information about the study can be found on ClinicalTrials.gov under the identifier NCT05098210.

A version of this article first appeared on WebMD.com.

Many women who got a COVID-19 vaccine have reported heavier bleeding during their periods since they had the shots.

A team of researchers investigated the trend and set out to find out who among the vaccinated were more likely to experience the menstruation changes.

The researchers were led by Katharine M.N. Lee, PhD, MS, of the division of public health sciences at Washington University in St. Louis. Their findings were published ahead of print in Science Advances.

The investigators analyzed more than 139,000 responses from an online survey from both currently and formerly menstruating women.

They found that, among people who have regular periods, about the same percentage had heavier bleeding after they got a COVID vaccine as had no change in bleeding after the vaccine (44% vs. 42%, respectively).

“A much smaller portion had lighter periods,” they write.

The phenomenon has been difficult to study because questions about changes in menstruation are not a standard part of vaccine trials.

Date of last period is often tracked in clinical trials to make sure a participant is not pregnant, but the questions about periods often stop there.

Additionally, periods are different for everyone and can be influenced by all sorts of environmental factors, so making associations regarding exposures is problematic.
 

No changes found to fertility

The authors emphasized that, generally, changes to menstrual bleeding are not uncommon nor dangerous. They also emphasized that the changes in bleeding don’t mean changes to fertility.

The uterine reproductive system is flexible when the body is under stress, they note.

“We know that running a marathon may influence hormone concentrations in the short term while not rendering that person infertile,” the authors write.

However, they acknowledge that investigating these reports is critical in building trust in medicine.

This report includes information that hasn’t been available through the clinical trial follow-up process.

For instance, the authors write, “To the best of our knowledge, our work is the first to examine breakthrough bleeding after vaccination in either pre- or postmenopausal people.”

Reports of changes to periods after vaccination started emerging in 2021. But without data, reports were largely dismissed, fueling criticism from those waging campaigns against COVID vaccines.

Dr. Lee and colleagues gathered data from those who responded to the online survey and detailed some trends.

People who were bleeding more heavily after vaccination were more likely to be older, Hispanic, had vaccine side effects of fever and fatigue, had been pregnant at some point, or had given birth.

People with regular periods who had endometriosis, prolonged bleeding during their periods, polycystic ovarian syndrome (PCOS) or fibroids were also more likely to have increased bleeding after a COVID vaccine.
 

Breakthrough bleeding

For people who don’t menstruate, but have not reached menopause, breakthrough bleeding happened more often in women who had been pregnant and/or had given birth.

Among respondents who were postmenopausal, breakthrough bleeding happened more often in younger people and/or those who are Hispanic.

More than a third of the respondents (39%) who use gender-affirming hormones that eliminate menstruation reported breakthrough bleeding after vaccination.

The majority of premenopausal people on long-acting, reversible contraception (71%) and the majority of postmenopausal respondents (66%) had breakthrough bleeding as well.

The authors note that you can’t compare the percentages who report these experiences in the survey with the incidence of those who would experience changes in menstrual bleeding in the general population.

The nature of the online survey means it may be naturally biased because the people who responded may be more often those who noted some change in their own menstrual experiences, particularly if that involved discomfort, pain, or fear.

Researchers also acknowledge that Black, Indigenous, Latinx, and other respondents of color are underrepresented in this research and that represents a limitation in the work.

Alison Edelman, MD, MPH, with the department of obstetrics and gynecology at Oregon Health & Science University in Portland, was not involved with Dr. Lee and associates’ study but has also studied the relationship between COVID vaccines and menstruation.

Her team’s study found that COVID vaccination is associated with a small change in time between periods but not length of periods.

She said about the work by Dr. Lee and colleagues, “This work really elevates the voices of the public and what they’re experiencing.”

The association makes sense, Dr. Edelman says, in that the reproductive system and the immune system talk to each other and inflammation in the immune system is going to be noticed by the system governing periods.

Lack of data on the relationship between exposures and menstruation didn’t start with COVID. “There has been a signal in the population before with other vaccines that’s been dismissed,” she said.

Tracking menstruation information in clinical trials can help physicians counsel women on what may be coming with any vaccine and alleviate fears and vaccine hesitancy, Dr. Edelman explained. It can also help vaccine developers know what to include in information about their product.

“When you are counseled about what to expect, it’s not as scary. That provides trust in the system,” she said. She likened it to original lack of data on whether COVID-19 vaccines would affect pregnancy.

“We have great science now that COVID vaccine does not affect fertility and [vaccine] does not impact pregnancy.”

Another important aspect of this paper is that it included subgroups not studied before regarding menstruation and breakthrough bleeding, such as those taking gender-affirming hormones, she added.

Menstruation has been often overlooked as important in clinical trial exposures but Dr. Edelman hopes this recent attention and question will escalate and prompt more research.

“I’m hoping with the immense outpouring from the public about how important this is, that future studies will look at this a little bit better,” she says.

She said when the National Institutes of Health opened up funding for trials on COVID-19 vaccines and menstruation, researchers got flooded with requests from women to share their stories.

“As a researcher – I’ve been doing research for over 20 years – that’s not something that usually happens. I would love to have that happen for every research project.”

The authors and Dr. Edelman declare that they have no competing interests. This research was supported in part by the University of Illinois Beckman Institute for Advanced Science and Technology, the University of Illinois Interdisciplinary Health Sciences Institute, the National Institutes of Health, the Foundation for Barnes-Jewish Hospital, and the Siteman Cancer Center.

Many women who got a COVID-19 vaccine have reported heavier bleeding during their periods since they had the shots.

A team of researchers investigated the trend and set out to find out who among the vaccinated were more likely to experience the menstruation changes.

The researchers were led by Katharine M.N. Lee, PhD, MS, of the division of public health sciences at Washington University in St. Louis. Their findings were published ahead of print in Science Advances.

The investigators analyzed more than 139,000 responses from an online survey from both currently and formerly menstruating women.

They found that, among people who have regular periods, about the same percentage had heavier bleeding after they got a COVID vaccine as had no change in bleeding after the vaccine (44% vs. 42%, respectively).

“A much smaller portion had lighter periods,” they write.

The phenomenon has been difficult to study because questions about changes in menstruation are not a standard part of vaccine trials.

Date of last period is often tracked in clinical trials to make sure a participant is not pregnant, but the questions about periods often stop there.

Additionally, periods are different for everyone and can be influenced by all sorts of environmental factors, so making associations regarding exposures is problematic.
 

No changes found to fertility

The authors emphasized that, generally, changes to menstrual bleeding are not uncommon nor dangerous. They also emphasized that the changes in bleeding don’t mean changes to fertility.

The uterine reproductive system is flexible when the body is under stress, they note.

“We know that running a marathon may influence hormone concentrations in the short term while not rendering that person infertile,” the authors write.

However, they acknowledge that investigating these reports is critical in building trust in medicine.

This report includes information that hasn’t been available through the clinical trial follow-up process.

For instance, the authors write, “To the best of our knowledge, our work is the first to examine breakthrough bleeding after vaccination in either pre- or postmenopausal people.”

Reports of changes to periods after vaccination started emerging in 2021. But without data, reports were largely dismissed, fueling criticism from those waging campaigns against COVID vaccines.

Dr. Lee and colleagues gathered data from those who responded to the online survey and detailed some trends.

People who were bleeding more heavily after vaccination were more likely to be older, Hispanic, had vaccine side effects of fever and fatigue, had been pregnant at some point, or had given birth.

People with regular periods who had endometriosis, prolonged bleeding during their periods, polycystic ovarian syndrome (PCOS) or fibroids were also more likely to have increased bleeding after a COVID vaccine.
 

Breakthrough bleeding

For people who don’t menstruate, but have not reached menopause, breakthrough bleeding happened more often in women who had been pregnant and/or had given birth.

Among respondents who were postmenopausal, breakthrough bleeding happened more often in younger people and/or those who are Hispanic.

More than a third of the respondents (39%) who use gender-affirming hormones that eliminate menstruation reported breakthrough bleeding after vaccination.

The majority of premenopausal people on long-acting, reversible contraception (71%) and the majority of postmenopausal respondents (66%) had breakthrough bleeding as well.

The authors note that you can’t compare the percentages who report these experiences in the survey with the incidence of those who would experience changes in menstrual bleeding in the general population.

The nature of the online survey means it may be naturally biased because the people who responded may be more often those who noted some change in their own menstrual experiences, particularly if that involved discomfort, pain, or fear.

Researchers also acknowledge that Black, Indigenous, Latinx, and other respondents of color are underrepresented in this research and that represents a limitation in the work.

Alison Edelman, MD, MPH, with the department of obstetrics and gynecology at Oregon Health & Science University in Portland, was not involved with Dr. Lee and associates’ study but has also studied the relationship between COVID vaccines and menstruation.

Her team’s study found that COVID vaccination is associated with a small change in time between periods but not length of periods.

She said about the work by Dr. Lee and colleagues, “This work really elevates the voices of the public and what they’re experiencing.”

The association makes sense, Dr. Edelman says, in that the reproductive system and the immune system talk to each other and inflammation in the immune system is going to be noticed by the system governing periods.

Lack of data on the relationship between exposures and menstruation didn’t start with COVID. “There has been a signal in the population before with other vaccines that’s been dismissed,” she said.

Tracking menstruation information in clinical trials can help physicians counsel women on what may be coming with any vaccine and alleviate fears and vaccine hesitancy, Dr. Edelman explained. It can also help vaccine developers know what to include in information about their product.

“When you are counseled about what to expect, it’s not as scary. That provides trust in the system,” she said. She likened it to original lack of data on whether COVID-19 vaccines would affect pregnancy.

“We have great science now that COVID vaccine does not affect fertility and [vaccine] does not impact pregnancy.”

Another important aspect of this paper is that it included subgroups not studied before regarding menstruation and breakthrough bleeding, such as those taking gender-affirming hormones, she added.

Menstruation has been often overlooked as important in clinical trial exposures but Dr. Edelman hopes this recent attention and question will escalate and prompt more research.

“I’m hoping with the immense outpouring from the public about how important this is, that future studies will look at this a little bit better,” she says.

She said when the National Institutes of Health opened up funding for trials on COVID-19 vaccines and menstruation, researchers got flooded with requests from women to share their stories.

“As a researcher – I’ve been doing research for over 20 years – that’s not something that usually happens. I would love to have that happen for every research project.”

The authors and Dr. Edelman declare that they have no competing interests. This research was supported in part by the University of Illinois Beckman Institute for Advanced Science and Technology, the University of Illinois Interdisciplinary Health Sciences Institute, the National Institutes of Health, the Foundation for Barnes-Jewish Hospital, and the Siteman Cancer Center.

Many women who got a COVID-19 vaccine have reported heavier bleeding during their periods since they had the shots.

A team of researchers investigated the trend and set out to find out who among the vaccinated were more likely to experience the menstruation changes.

The researchers were led by Katharine M.N. Lee, PhD, MS, of the division of public health sciences at Washington University in St. Louis. Their findings were published ahead of print in Science Advances.

The investigators analyzed more than 139,000 responses from an online survey from both currently and formerly menstruating women.

They found that, among people who have regular periods, about the same percentage had heavier bleeding after they got a COVID vaccine as had no change in bleeding after the vaccine (44% vs. 42%, respectively).

“A much smaller portion had lighter periods,” they write.

The phenomenon has been difficult to study because questions about changes in menstruation are not a standard part of vaccine trials.

Date of last period is often tracked in clinical trials to make sure a participant is not pregnant, but the questions about periods often stop there.

Additionally, periods are different for everyone and can be influenced by all sorts of environmental factors, so making associations regarding exposures is problematic.
 

No changes found to fertility

The authors emphasized that, generally, changes to menstrual bleeding are not uncommon nor dangerous. They also emphasized that the changes in bleeding don’t mean changes to fertility.

The uterine reproductive system is flexible when the body is under stress, they note.

“We know that running a marathon may influence hormone concentrations in the short term while not rendering that person infertile,” the authors write.

However, they acknowledge that investigating these reports is critical in building trust in medicine.

This report includes information that hasn’t been available through the clinical trial follow-up process.

For instance, the authors write, “To the best of our knowledge, our work is the first to examine breakthrough bleeding after vaccination in either pre- or postmenopausal people.”

Reports of changes to periods after vaccination started emerging in 2021. But without data, reports were largely dismissed, fueling criticism from those waging campaigns against COVID vaccines.

Dr. Lee and colleagues gathered data from those who responded to the online survey and detailed some trends.

People who were bleeding more heavily after vaccination were more likely to be older, Hispanic, had vaccine side effects of fever and fatigue, had been pregnant at some point, or had given birth.

People with regular periods who had endometriosis, prolonged bleeding during their periods, polycystic ovarian syndrome (PCOS) or fibroids were also more likely to have increased bleeding after a COVID vaccine.
 

Breakthrough bleeding

For people who don’t menstruate, but have not reached menopause, breakthrough bleeding happened more often in women who had been pregnant and/or had given birth.

Among respondents who were postmenopausal, breakthrough bleeding happened more often in younger people and/or those who are Hispanic.

More than a third of the respondents (39%) who use gender-affirming hormones that eliminate menstruation reported breakthrough bleeding after vaccination.

The majority of premenopausal people on long-acting, reversible contraception (71%) and the majority of postmenopausal respondents (66%) had breakthrough bleeding as well.

The authors note that you can’t compare the percentages who report these experiences in the survey with the incidence of those who would experience changes in menstrual bleeding in the general population.

The nature of the online survey means it may be naturally biased because the people who responded may be more often those who noted some change in their own menstrual experiences, particularly if that involved discomfort, pain, or fear.

Researchers also acknowledge that Black, Indigenous, Latinx, and other respondents of color are underrepresented in this research and that represents a limitation in the work.

Alison Edelman, MD, MPH, with the department of obstetrics and gynecology at Oregon Health & Science University in Portland, was not involved with Dr. Lee and associates’ study but has also studied the relationship between COVID vaccines and menstruation.

Her team’s study found that COVID vaccination is associated with a small change in time between periods but not length of periods.

She said about the work by Dr. Lee and colleagues, “This work really elevates the voices of the public and what they’re experiencing.”

The association makes sense, Dr. Edelman says, in that the reproductive system and the immune system talk to each other and inflammation in the immune system is going to be noticed by the system governing periods.

Lack of data on the relationship between exposures and menstruation didn’t start with COVID. “There has been a signal in the population before with other vaccines that’s been dismissed,” she said.

Tracking menstruation information in clinical trials can help physicians counsel women on what may be coming with any vaccine and alleviate fears and vaccine hesitancy, Dr. Edelman explained. It can also help vaccine developers know what to include in information about their product.

“When you are counseled about what to expect, it’s not as scary. That provides trust in the system,” she said. She likened it to original lack of data on whether COVID-19 vaccines would affect pregnancy.

“We have great science now that COVID vaccine does not affect fertility and [vaccine] does not impact pregnancy.”

Another important aspect of this paper is that it included subgroups not studied before regarding menstruation and breakthrough bleeding, such as those taking gender-affirming hormones, she added.

Menstruation has been often overlooked as important in clinical trial exposures but Dr. Edelman hopes this recent attention and question will escalate and prompt more research.

“I’m hoping with the immense outpouring from the public about how important this is, that future studies will look at this a little bit better,” she says.

She said when the National Institutes of Health opened up funding for trials on COVID-19 vaccines and menstruation, researchers got flooded with requests from women to share their stories.

“As a researcher – I’ve been doing research for over 20 years – that’s not something that usually happens. I would love to have that happen for every research project.”

The authors and Dr. Edelman declare that they have no competing interests. This research was supported in part by the University of Illinois Beckman Institute for Advanced Science and Technology, the University of Illinois Interdisciplinary Health Sciences Institute, the National Institutes of Health, the Foundation for Barnes-Jewish Hospital, and the Siteman Cancer Center.

Americans could soon have a fourth option for COVID-19 vaccines after the Food and Drug Administration granted emergency use authorization to a two-shot vaccine from Novavax on July 13.

The vaccine is authorized for adults only. Should the Centers for Disease Control and Prevention follow suit and approve its use, Novavax would join Moderna, Pfizer and Johnson & Johnson on the U.S. market. A CDC panel of advisors is expected to consider the new entry on July 19.

The Novavax vaccine is only for those who have not yet been vaccinated at all.

“Today’s authorization offers adults in the United States who have not yet received a COVID-19 vaccine another option that meets the FDA’s rigorous standards for safety, effectiveness and manufacturing quality needed to support emergency use authorization,” FDA Commissioner Robert Califf, MD, said in a statement. “COVID-19 vaccines remain the best preventive measure against severe disease caused by COVID-19 and I encourage anyone who is eligible for, but has not yet received a COVID-19 vaccine, to consider doing so.”

The Novavax vaccine is protein-based, making it different than mRNA vaccines from Pfizer and Moderna. It contains harmless elements of actual coronavirus spike protein and an ingredient known as a adjuvant that enhances the patient’s immune response.

Clinical trials found the vaccine to be 90.4% effective in preventing mild, moderate or severe COVID-19. Only 17 patients out of 17,200 developed COVID-19 after receiving both doses.

The FDA said, however, that Novavax’s vaccine did show evidence of increased risk of myocarditis – inflammation of the heart – and pericarditis, inflammation of tissue surrounding the heart. In most people both disorders began within 10 days.

A version of this article first appeared on WebMD.com.

Americans could soon have a fourth option for COVID-19 vaccines after the Food and Drug Administration granted emergency use authorization to a two-shot vaccine from Novavax on July 13.

The vaccine is authorized for adults only. Should the Centers for Disease Control and Prevention follow suit and approve its use, Novavax would join Moderna, Pfizer and Johnson & Johnson on the U.S. market. A CDC panel of advisors is expected to consider the new entry on July 19.

The Novavax vaccine is only for those who have not yet been vaccinated at all.

“Today’s authorization offers adults in the United States who have not yet received a COVID-19 vaccine another option that meets the FDA’s rigorous standards for safety, effectiveness and manufacturing quality needed to support emergency use authorization,” FDA Commissioner Robert Califf, MD, said in a statement. “COVID-19 vaccines remain the best preventive measure against severe disease caused by COVID-19 and I encourage anyone who is eligible for, but has not yet received a COVID-19 vaccine, to consider doing so.”

The Novavax vaccine is protein-based, making it different than mRNA vaccines from Pfizer and Moderna. It contains harmless elements of actual coronavirus spike protein and an ingredient known as a adjuvant that enhances the patient’s immune response.

Clinical trials found the vaccine to be 90.4% effective in preventing mild, moderate or severe COVID-19. Only 17 patients out of 17,200 developed COVID-19 after receiving both doses.

The FDA said, however, that Novavax’s vaccine did show evidence of increased risk of myocarditis – inflammation of the heart – and pericarditis, inflammation of tissue surrounding the heart. In most people both disorders began within 10 days.

A version of this article first appeared on WebMD.com.

Americans could soon have a fourth option for COVID-19 vaccines after the Food and Drug Administration granted emergency use authorization to a two-shot vaccine from Novavax on July 13.

The vaccine is authorized for adults only. Should the Centers for Disease Control and Prevention follow suit and approve its use, Novavax would join Moderna, Pfizer and Johnson & Johnson on the U.S. market. A CDC panel of advisors is expected to consider the new entry on July 19.

The Novavax vaccine is only for those who have not yet been vaccinated at all.

“Today’s authorization offers adults in the United States who have not yet received a COVID-19 vaccine another option that meets the FDA’s rigorous standards for safety, effectiveness and manufacturing quality needed to support emergency use authorization,” FDA Commissioner Robert Califf, MD, said in a statement. “COVID-19 vaccines remain the best preventive measure against severe disease caused by COVID-19 and I encourage anyone who is eligible for, but has not yet received a COVID-19 vaccine, to consider doing so.”

The Novavax vaccine is protein-based, making it different than mRNA vaccines from Pfizer and Moderna. It contains harmless elements of actual coronavirus spike protein and an ingredient known as a adjuvant that enhances the patient’s immune response.

Clinical trials found the vaccine to be 90.4% effective in preventing mild, moderate or severe COVID-19. Only 17 patients out of 17,200 developed COVID-19 after receiving both doses.

The FDA said, however, that Novavax’s vaccine did show evidence of increased risk of myocarditis – inflammation of the heart – and pericarditis, inflammation of tissue surrounding the heart. In most people both disorders began within 10 days.

A version of this article first appeared on WebMD.com.

A retrospective investigation using medical claims data found no elevated risk of disease flares in patients with immune-mediated inflammatory diseases (IMIDs) who received the recombinant zoster vaccine (RZV), according to research published in Arthritis & Rheumatology.

The authors of the study noted that individuals with IMIDs are at increased risk for herpes zoster and related complications, including postherpetic neuralgia, and that vaccination has been recommended for certain groups of patients with rheumatoid arthritis, inflammatory bowel disease, and psoriasis, by the American College of Rheumatology and other professional organizations for individuals aged 50 and older.

The study investigators used medical claims from IBM MarketScan, which provided data on patients aged 50-64 years, and data from the Centers for Medicare and Medicaid Services’ Medicare on patients aged 65 and older.

They defined presumed flares in three ways: hospitalization/emergency department visits for IMIDs, steroid treatment with a short-acting oral glucocorticoid, or treatment with a parenteral glucocorticoid injection. The investigators conducted a self-controlled case series (SCCS) analysis to examine any temporal link between the RZV and disease flares.

Among enrollees with IMIDs, 14.8% of the 55,654 patients in the MarketScan database and 43.2% of the 160,545 patients in the Medicare database received at least one dose of RZV during 2018-2019. The two-dose series completion within 6 months was 76.6% in the MarketScan group (age range, 50-64 years) and 85.4% among Medicare enrollees (age range, 65 years and older). In the SCCS analysis, 10% and 13% of patients developed flares in the control group as compared to 9%, and 11%-12% in the risk window following one or two doses of RZV among MarketScan and Medicare enrollees, respectively.

Based on these findings, the investigators concluded there was no statistically significant increase in flares subsequent to RZV administration for any IMID in either patients aged 50-64 years or patients aged 65 years and older following the first dose or second dose.

Nilanjana Bose, MD, a rheumatologist with Lonestar Rheumatology, Houston, Texas, who was not involved with the study, said that the research addresses a topic where there is uneasiness, namely vaccination in patients with IMIDs.

A retrospective investigation using medical claims data found no elevated risk of disease flares in patients with immune-mediated inflammatory diseases (IMIDs) who received the recombinant zoster vaccine (RZV), according to research published in Arthritis & Rheumatology.

The authors of the study noted that individuals with IMIDs are at increased risk for herpes zoster and related complications, including postherpetic neuralgia, and that vaccination has been recommended for certain groups of patients with rheumatoid arthritis, inflammatory bowel disease, and psoriasis, by the American College of Rheumatology and other professional organizations for individuals aged 50 and older.

The study investigators used medical claims from IBM MarketScan, which provided data on patients aged 50-64 years, and data from the Centers for Medicare and Medicaid Services’ Medicare on patients aged 65 and older.

They defined presumed flares in three ways: hospitalization/emergency department visits for IMIDs, steroid treatment with a short-acting oral glucocorticoid, or treatment with a parenteral glucocorticoid injection. The investigators conducted a self-controlled case series (SCCS) analysis to examine any temporal link between the RZV and disease flares.

Among enrollees with IMIDs, 14.8% of the 55,654 patients in the MarketScan database and 43.2% of the 160,545 patients in the Medicare database received at least one dose of RZV during 2018-2019. The two-dose series completion within 6 months was 76.6% in the MarketScan group (age range, 50-64 years) and 85.4% among Medicare enrollees (age range, 65 years and older). In the SCCS analysis, 10% and 13% of patients developed flares in the control group as compared to 9%, and 11%-12% in the risk window following one or two doses of RZV among MarketScan and Medicare enrollees, respectively.

Based on these findings, the investigators concluded there was no statistically significant increase in flares subsequent to RZV administration for any IMID in either patients aged 50-64 years or patients aged 65 years and older following the first dose or second dose.

Nilanjana Bose, MD, a rheumatologist with Lonestar Rheumatology, Houston, Texas, who was not involved with the study, said that the research addresses a topic where there is uneasiness, namely vaccination in patients with IMIDs.

A retrospective investigation using medical claims data found no elevated risk of disease flares in patients with immune-mediated inflammatory diseases (IMIDs) who received the recombinant zoster vaccine (RZV), according to research published in Arthritis & Rheumatology.

The authors of the study noted that individuals with IMIDs are at increased risk for herpes zoster and related complications, including postherpetic neuralgia, and that vaccination has been recommended for certain groups of patients with rheumatoid arthritis, inflammatory bowel disease, and psoriasis, by the American College of Rheumatology and other professional organizations for individuals aged 50 and older.

The study investigators used medical claims from IBM MarketScan, which provided data on patients aged 50-64 years, and data from the Centers for Medicare and Medicaid Services’ Medicare on patients aged 65 and older.

They defined presumed flares in three ways: hospitalization/emergency department visits for IMIDs, steroid treatment with a short-acting oral glucocorticoid, or treatment with a parenteral glucocorticoid injection. The investigators conducted a self-controlled case series (SCCS) analysis to examine any temporal link between the RZV and disease flares.

Among enrollees with IMIDs, 14.8% of the 55,654 patients in the MarketScan database and 43.2% of the 160,545 patients in the Medicare database received at least one dose of RZV during 2018-2019. The two-dose series completion within 6 months was 76.6% in the MarketScan group (age range, 50-64 years) and 85.4% among Medicare enrollees (age range, 65 years and older). In the SCCS analysis, 10% and 13% of patients developed flares in the control group as compared to 9%, and 11%-12% in the risk window following one or two doses of RZV among MarketScan and Medicare enrollees, respectively.

Based on these findings, the investigators concluded there was no statistically significant increase in flares subsequent to RZV administration for any IMID in either patients aged 50-64 years or patients aged 65 years and older following the first dose or second dose.

Nilanjana Bose, MD, a rheumatologist with Lonestar Rheumatology, Houston, Texas, who was not involved with the study, said that the research addresses a topic where there is uneasiness, namely vaccination in patients with IMIDs.

A family’s decision to vaccinate their child is best made jointly with a trusted medical provider who knows the child and family. The American Academy of Pediatrics created a toolkit with resources for answering questions about the recently authorized SARS-CoV-2 mRNA vaccines (Pfizer and Moderna) for 6-month- to 5-year-olds with science-backed vaccine facts, including links to other useful AAP information websites, talking points, graphics, and videos.¹

SARS-CoV-2 seasonality

SARS-CoV-2 is now endemic, not a once-a-year seasonal virus. Seasons (aka surges) will occur whenever a new variant arises (twice yearly since 2020, Omicron BA.4/BA.5 currently), or when enough vaccine holdouts, newborns, and/or those with waning of prior immunity (vaccine or infection induced) accrue.

Emergency use authorization submission data for mRNA vaccine responses in young children^2,3

Moderna in 6-month- through 5-year-olds. Two 25-mcg doses given 4-8 weeks apart produced 37.8% (95% confidence interval, 20.9%-51.1%) protection against symptomatic Omicron SARS-CoV-2 infections through 3 months of follow-up. Immunobridging analysis of antibody responses compared to 18- to 25-year-olds (100-mcg doses) showed the children’s responses were noninferior. Thus, the committee inferred that vaccine effectiveness in children should be similar to that in 18- to 25-year-olds. Fever, irritability, or local reaction/pain occurred in two-thirds after the second dose. Grade 3 reactions were noted in less than 5%.

Pfizer in 6-month- through 4-year-olds. Three 3-mcg doses, two doses 3-8 weeks apart and the third dose at least 8 weeks later (median 16 weeks), produced 80.3% (95% CI, 13.9%-96.7%) protection against symptomatic COVID-19 during the 6 weeks after the third dose. Local and systemic reactions occurred in 63.8%; less than 5% had grade 3 reactions (fever in about 3%, irritability in 1.3%, fatigue in 0.8%) mostly after second dose.

Neither duration of follow-up is very long. The Moderna data tell me that a third primary dose would have been better but restarting the trial to evaluate third doses would have delayed Moderna’s EUA another 4-6 months. The three-dose Pfizer data look better but may not have been as good with another 6 weeks of follow-up.

Additional post-EUA data will be collected. Boosters will be needed when immunity from both vaccines wanes (one estimate is about 6 months after the primary series). The Advisory Committee on Immunization Practices noted in their deliberations that vaccine-induced antibody responses are higher and cross-neutralize variants (even Omicron) better than infection-induced immunity.⁴

Are there downsides to the vaccines? Naysayers question vaccinating children less than 5 years old with reasons containing enough “truth” that they catch people’s attention, for example, “young children don’t get very sick with COVID-19,” “most have been infected already,” “RNA for the spike protein stays in the body for months,” or “myocarditis.” Naysayers can quote references in reputable journals but seem to spin selected data out of context or quote unconfirmed data from the Vaccine Adverse Event Reporting System.
 

Reasons to vaccinate

• While children have milder disease than adults, mid-June 2022 surveillance indicated 50 hospitalizations and 1 pediatric death each day from SARS-CoV-2.⁵
• Vaccinating young children endows a foundation of vaccine-induced SARS-CoV-2 immunity that is superior to infection-induced immunity.⁴
• Long-term effects of large numbers of SARS-CoV-2 particles that enter every organ of a developing child have not been determined.
• Viral loads are lowered by prior vaccine; fewer viral replications lessen chances for newer variants to arise.
• Transmission is less in breakthrough infections than infections in the unvaccinated.
• Thirty percent of 5- to 11-year-olds hospitalized for SARS-CoV-2 had no underlying conditions;⁶ hospitalization rates in newborn to 4-year-olds have been the highest in the Omicron surge.⁷
• No myocarditis or pericarditis episodes have been detected in 6-month- to 11-year-old trials.
• The AAP and ACIP recommend the mRNA vaccines.

My thoughts are that SARS-CoV-2 vaccine is just another “routine” childhood vaccine that prepares children for healthier futures, pandemic or not, and the vaccines are as safe as other routine vaccines.

And like other pediatric vaccines, it should be no surprise that boosters will be needed, even if no newer variants than Omicron BA.4/BA.5 arise. But we know newer variants will arise and, similar to influenza vaccine, new formulations, perhaps with multiple SARS-CoV-2 strain antigens, will be needed every year or so. Everyone will get SARS-CoV-2 multiple times in their lives no matter how careful they are. So isn’t it good medical practice to establish early the best available foundation for maintaining lifelong SARS-CoV-2 immunity?

To me it is like pertussis. Most pertussis-infected children are sick enough to be hospitalized; very few die. They are miserable with illnesses that take weeks to months to subside. The worst disease usually occurs in unvaccinated young children or those with underlying conditions. Reactogenicity was reduced with acellular vaccine but resulted in less immunogenicity, so we give boosters at intervals that best match waning immunity. Circulating strains can be different than the vaccine strain, so protection against infection is 80%. Finally, even the safest vaccine may very rarely have sequelae. That is why The National Vaccine Injury Compensation Program was created. Yet the benefit-to-harm ratio for children and society favors universal pertussis vaccine use. And we vaccinate even those who have had pertussis because even infection-based immunity is incomplete and protection wanes. If arguments similar to those by SARS-CoV-2 vaccine naysayers were applied to acellular pertussis vaccine, it seems they would argue against pertussis vaccine for young children.

Another major issue has been “safety concerns” about the vaccines’ small amount of mRNA for the spike protein encased in microscopic lipid bubbles injected in the arm or leg. This mRNA is picked up by human cells, and in the cytoplasm (not the nucleus where our DNA resides) produces a limited supply of spike protein that is then picked up by antigen-presenting cells for short-lived distribution (days to 2 weeks at most) to regional lymph nodes where immune-memory processes are jump-started. Contrast that to even asymptomatic SARS-CoV-2 infection where multibillions of virus particles are produced for up to 14 days with access to every bodily organ that contains ACE-2 receptors (they all do). Each virus particle hijacks a human cell producing thousands of mRNA for spike protein (and multiple other SARS-CoV-2 proteins), eventually releasing multibillions of lipid fragments from the ruptured cell. Comparing the amount of these components in the mRNA vaccines to those from infection is like comparing a campfire to the many-thousand-acre wildfire. So, if one is worried about the effects of spike protein and lipid fragments, the limited localized amounts in mRNA vaccines should make one much less concerned than the enormous amounts circulating throughout the body as a result of a SARS-CoV-2 infection.

My take is that children 6-months to 5-years-old deserve SARS-CoV-2–induced vaccine protection and we can and should strongly recommend it as medical providers and child advocates.
 

*Dr. Harrison is professor, University of Missouri Kansas City School of Medicine, department of medicine, infectious diseases section, Kansas City. Email him at pdnews@mdedge.com.

References

1. AAP. 2022 Jun 21. As COVID-19 vaccines become available for children ages 6 months to 4 years, AAP urges families to reach out to pediatricians to ask questions and access vaccine. www.aap.org.

2. CDC. Grading of recommendations, assessment, development, and evaluation (GRADE): Moderna COVID-19 vaccine for children aged 6 months–5 years. www.cdc.gov.

3. CDC. ACIP evidence to recommendations for use of Moderna COVID-19 vaccine in children ages 6 months–5 years and Pfizer-BioNTech COVID-19 vaccine in children ages 6 months–4 years under an emergency use authorization. www.cdc.gov.

4. Tang J et al. Nat Commun. 2022;13:2979.

5. Children and COVID-19: State Data Report. 2022 Jun 30. www.aap.org.

6. Shi DS et al. MMWR Morb Mortal Wkly Rep. 2022;71:574-81.

7. Marks KJ et al. MMWR Morb Mortal Wkly Rep. 2022;71:429-36.
 

Other good resources for families are https://getvaccineanswers.org/ or www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-in-babies-and-children/art-20484405.

*This story was updated on July 19, 2022.

A family’s decision to vaccinate their child is best made jointly with a trusted medical provider who knows the child and family. The American Academy of Pediatrics created a toolkit with resources for answering questions about the recently authorized SARS-CoV-2 mRNA vaccines (Pfizer and Moderna) for 6-month- to 5-year-olds with science-backed vaccine facts, including links to other useful AAP information websites, talking points, graphics, and videos.¹

SARS-CoV-2 seasonality

SARS-CoV-2 is now endemic, not a once-a-year seasonal virus. Seasons (aka surges) will occur whenever a new variant arises (twice yearly since 2020, Omicron BA.4/BA.5 currently), or when enough vaccine holdouts, newborns, and/or those with waning of prior immunity (vaccine or infection induced) accrue.

Emergency use authorization submission data for mRNA vaccine responses in young children^2,3

Moderna in 6-month- through 5-year-olds. Two 25-mcg doses given 4-8 weeks apart produced 37.8% (95% confidence interval, 20.9%-51.1%) protection against symptomatic Omicron SARS-CoV-2 infections through 3 months of follow-up. Immunobridging analysis of antibody responses compared to 18- to 25-year-olds (100-mcg doses) showed the children’s responses were noninferior. Thus, the committee inferred that vaccine effectiveness in children should be similar to that in 18- to 25-year-olds. Fever, irritability, or local reaction/pain occurred in two-thirds after the second dose. Grade 3 reactions were noted in less than 5%.

Pfizer in 6-month- through 4-year-olds. Three 3-mcg doses, two doses 3-8 weeks apart and the third dose at least 8 weeks later (median 16 weeks), produced 80.3% (95% CI, 13.9%-96.7%) protection against symptomatic COVID-19 during the 6 weeks after the third dose. Local and systemic reactions occurred in 63.8%; less than 5% had grade 3 reactions (fever in about 3%, irritability in 1.3%, fatigue in 0.8%) mostly after second dose.

Neither duration of follow-up is very long. The Moderna data tell me that a third primary dose would have been better but restarting the trial to evaluate third doses would have delayed Moderna’s EUA another 4-6 months. The three-dose Pfizer data look better but may not have been as good with another 6 weeks of follow-up.

Additional post-EUA data will be collected. Boosters will be needed when immunity from both vaccines wanes (one estimate is about 6 months after the primary series). The Advisory Committee on Immunization Practices noted in their deliberations that vaccine-induced antibody responses are higher and cross-neutralize variants (even Omicron) better than infection-induced immunity.⁴

Are there downsides to the vaccines? Naysayers question vaccinating children less than 5 years old with reasons containing enough “truth” that they catch people’s attention, for example, “young children don’t get very sick with COVID-19,” “most have been infected already,” “RNA for the spike protein stays in the body for months,” or “myocarditis.” Naysayers can quote references in reputable journals but seem to spin selected data out of context or quote unconfirmed data from the Vaccine Adverse Event Reporting System.
 

Reasons to vaccinate

• While children have milder disease than adults, mid-June 2022 surveillance indicated 50 hospitalizations and 1 pediatric death each day from SARS-CoV-2.⁵
• Vaccinating young children endows a foundation of vaccine-induced SARS-CoV-2 immunity that is superior to infection-induced immunity.⁴
• Long-term effects of large numbers of SARS-CoV-2 particles that enter every organ of a developing child have not been determined.
• Viral loads are lowered by prior vaccine; fewer viral replications lessen chances for newer variants to arise.
• Transmission is less in breakthrough infections than infections in the unvaccinated.
• Thirty percent of 5- to 11-year-olds hospitalized for SARS-CoV-2 had no underlying conditions;⁶ hospitalization rates in newborn to 4-year-olds have been the highest in the Omicron surge.⁷
• No myocarditis or pericarditis episodes have been detected in 6-month- to 11-year-old trials.
• The AAP and ACIP recommend the mRNA vaccines.

My thoughts are that SARS-CoV-2 vaccine is just another “routine” childhood vaccine that prepares children for healthier futures, pandemic or not, and the vaccines are as safe as other routine vaccines.

And like other pediatric vaccines, it should be no surprise that boosters will be needed, even if no newer variants than Omicron BA.4/BA.5 arise. But we know newer variants will arise and, similar to influenza vaccine, new formulations, perhaps with multiple SARS-CoV-2 strain antigens, will be needed every year or so. Everyone will get SARS-CoV-2 multiple times in their lives no matter how careful they are. So isn’t it good medical practice to establish early the best available foundation for maintaining lifelong SARS-CoV-2 immunity?

To me it is like pertussis. Most pertussis-infected children are sick enough to be hospitalized; very few die. They are miserable with illnesses that take weeks to months to subside. The worst disease usually occurs in unvaccinated young children or those with underlying conditions. Reactogenicity was reduced with acellular vaccine but resulted in less immunogenicity, so we give boosters at intervals that best match waning immunity. Circulating strains can be different than the vaccine strain, so protection against infection is 80%. Finally, even the safest vaccine may very rarely have sequelae. That is why The National Vaccine Injury Compensation Program was created. Yet the benefit-to-harm ratio for children and society favors universal pertussis vaccine use. And we vaccinate even those who have had pertussis because even infection-based immunity is incomplete and protection wanes. If arguments similar to those by SARS-CoV-2 vaccine naysayers were applied to acellular pertussis vaccine, it seems they would argue against pertussis vaccine for young children.

Another major issue has been “safety concerns” about the vaccines’ small amount of mRNA for the spike protein encased in microscopic lipid bubbles injected in the arm or leg. This mRNA is picked up by human cells, and in the cytoplasm (not the nucleus where our DNA resides) produces a limited supply of spike protein that is then picked up by antigen-presenting cells for short-lived distribution (days to 2 weeks at most) to regional lymph nodes where immune-memory processes are jump-started. Contrast that to even asymptomatic SARS-CoV-2 infection where multibillions of virus particles are produced for up to 14 days with access to every bodily organ that contains ACE-2 receptors (they all do). Each virus particle hijacks a human cell producing thousands of mRNA for spike protein (and multiple other SARS-CoV-2 proteins), eventually releasing multibillions of lipid fragments from the ruptured cell. Comparing the amount of these components in the mRNA vaccines to those from infection is like comparing a campfire to the many-thousand-acre wildfire. So, if one is worried about the effects of spike protein and lipid fragments, the limited localized amounts in mRNA vaccines should make one much less concerned than the enormous amounts circulating throughout the body as a result of a SARS-CoV-2 infection.

My take is that children 6-months to 5-years-old deserve SARS-CoV-2–induced vaccine protection and we can and should strongly recommend it as medical providers and child advocates.
 

*Dr. Harrison is professor, University of Missouri Kansas City School of Medicine, department of medicine, infectious diseases section, Kansas City. Email him at pdnews@mdedge.com.

References

1. AAP. 2022 Jun 21. As COVID-19 vaccines become available for children ages 6 months to 4 years, AAP urges families to reach out to pediatricians to ask questions and access vaccine. www.aap.org.

2. CDC. Grading of recommendations, assessment, development, and evaluation (GRADE): Moderna COVID-19 vaccine for children aged 6 months–5 years. www.cdc.gov.

3. CDC. ACIP evidence to recommendations for use of Moderna COVID-19 vaccine in children ages 6 months–5 years and Pfizer-BioNTech COVID-19 vaccine in children ages 6 months–4 years under an emergency use authorization. www.cdc.gov.

4. Tang J et al. Nat Commun. 2022;13:2979.

5. Children and COVID-19: State Data Report. 2022 Jun 30. www.aap.org.

6. Shi DS et al. MMWR Morb Mortal Wkly Rep. 2022;71:574-81.

7. Marks KJ et al. MMWR Morb Mortal Wkly Rep. 2022;71:429-36.
 

Other good resources for families are https://getvaccineanswers.org/ or www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-in-babies-and-children/art-20484405.

*This story was updated on July 19, 2022.

A family’s decision to vaccinate their child is best made jointly with a trusted medical provider who knows the child and family. The American Academy of Pediatrics created a toolkit with resources for answering questions about the recently authorized SARS-CoV-2 mRNA vaccines (Pfizer and Moderna) for 6-month- to 5-year-olds with science-backed vaccine facts, including links to other useful AAP information websites, talking points, graphics, and videos.¹

SARS-CoV-2 seasonality

SARS-CoV-2 is now endemic, not a once-a-year seasonal virus. Seasons (aka surges) will occur whenever a new variant arises (twice yearly since 2020, Omicron BA.4/BA.5 currently), or when enough vaccine holdouts, newborns, and/or those with waning of prior immunity (vaccine or infection induced) accrue.

Emergency use authorization submission data for mRNA vaccine responses in young children^2,3

Moderna in 6-month- through 5-year-olds. Two 25-mcg doses given 4-8 weeks apart produced 37.8% (95% confidence interval, 20.9%-51.1%) protection against symptomatic Omicron SARS-CoV-2 infections through 3 months of follow-up. Immunobridging analysis of antibody responses compared to 18- to 25-year-olds (100-mcg doses) showed the children’s responses were noninferior. Thus, the committee inferred that vaccine effectiveness in children should be similar to that in 18- to 25-year-olds. Fever, irritability, or local reaction/pain occurred in two-thirds after the second dose. Grade 3 reactions were noted in less than 5%.

Pfizer in 6-month- through 4-year-olds. Three 3-mcg doses, two doses 3-8 weeks apart and the third dose at least 8 weeks later (median 16 weeks), produced 80.3% (95% CI, 13.9%-96.7%) protection against symptomatic COVID-19 during the 6 weeks after the third dose. Local and systemic reactions occurred in 63.8%; less than 5% had grade 3 reactions (fever in about 3%, irritability in 1.3%, fatigue in 0.8%) mostly after second dose.

Neither duration of follow-up is very long. The Moderna data tell me that a third primary dose would have been better but restarting the trial to evaluate third doses would have delayed Moderna’s EUA another 4-6 months. The three-dose Pfizer data look better but may not have been as good with another 6 weeks of follow-up.

Additional post-EUA data will be collected. Boosters will be needed when immunity from both vaccines wanes (one estimate is about 6 months after the primary series). The Advisory Committee on Immunization Practices noted in their deliberations that vaccine-induced antibody responses are higher and cross-neutralize variants (even Omicron) better than infection-induced immunity.⁴

Are there downsides to the vaccines? Naysayers question vaccinating children less than 5 years old with reasons containing enough “truth” that they catch people’s attention, for example, “young children don’t get very sick with COVID-19,” “most have been infected already,” “RNA for the spike protein stays in the body for months,” or “myocarditis.” Naysayers can quote references in reputable journals but seem to spin selected data out of context or quote unconfirmed data from the Vaccine Adverse Event Reporting System.
 

Reasons to vaccinate

• While children have milder disease than adults, mid-June 2022 surveillance indicated 50 hospitalizations and 1 pediatric death each day from SARS-CoV-2.⁵
• Vaccinating young children endows a foundation of vaccine-induced SARS-CoV-2 immunity that is superior to infection-induced immunity.⁴
• Long-term effects of large numbers of SARS-CoV-2 particles that enter every organ of a developing child have not been determined.
• Viral loads are lowered by prior vaccine; fewer viral replications lessen chances for newer variants to arise.
• Transmission is less in breakthrough infections than infections in the unvaccinated.
• Thirty percent of 5- to 11-year-olds hospitalized for SARS-CoV-2 had no underlying conditions;⁶ hospitalization rates in newborn to 4-year-olds have been the highest in the Omicron surge.⁷
• No myocarditis or pericarditis episodes have been detected in 6-month- to 11-year-old trials.
• The AAP and ACIP recommend the mRNA vaccines.

My thoughts are that SARS-CoV-2 vaccine is just another “routine” childhood vaccine that prepares children for healthier futures, pandemic or not, and the vaccines are as safe as other routine vaccines.

And like other pediatric vaccines, it should be no surprise that boosters will be needed, even if no newer variants than Omicron BA.4/BA.5 arise. But we know newer variants will arise and, similar to influenza vaccine, new formulations, perhaps with multiple SARS-CoV-2 strain antigens, will be needed every year or so. Everyone will get SARS-CoV-2 multiple times in their lives no matter how careful they are. So isn’t it good medical practice to establish early the best available foundation for maintaining lifelong SARS-CoV-2 immunity?

To me it is like pertussis. Most pertussis-infected children are sick enough to be hospitalized; very few die. They are miserable with illnesses that take weeks to months to subside. The worst disease usually occurs in unvaccinated young children or those with underlying conditions. Reactogenicity was reduced with acellular vaccine but resulted in less immunogenicity, so we give boosters at intervals that best match waning immunity. Circulating strains can be different than the vaccine strain, so protection against infection is 80%. Finally, even the safest vaccine may very rarely have sequelae. That is why The National Vaccine Injury Compensation Program was created. Yet the benefit-to-harm ratio for children and society favors universal pertussis vaccine use. And we vaccinate even those who have had pertussis because even infection-based immunity is incomplete and protection wanes. If arguments similar to those by SARS-CoV-2 vaccine naysayers were applied to acellular pertussis vaccine, it seems they would argue against pertussis vaccine for young children.

Another major issue has been “safety concerns” about the vaccines’ small amount of mRNA for the spike protein encased in microscopic lipid bubbles injected in the arm or leg. This mRNA is picked up by human cells, and in the cytoplasm (not the nucleus where our DNA resides) produces a limited supply of spike protein that is then picked up by antigen-presenting cells for short-lived distribution (days to 2 weeks at most) to regional lymph nodes where immune-memory processes are jump-started. Contrast that to even asymptomatic SARS-CoV-2 infection where multibillions of virus particles are produced for up to 14 days with access to every bodily organ that contains ACE-2 receptors (they all do). Each virus particle hijacks a human cell producing thousands of mRNA for spike protein (and multiple other SARS-CoV-2 proteins), eventually releasing multibillions of lipid fragments from the ruptured cell. Comparing the amount of these components in the mRNA vaccines to those from infection is like comparing a campfire to the many-thousand-acre wildfire. So, if one is worried about the effects of spike protein and lipid fragments, the limited localized amounts in mRNA vaccines should make one much less concerned than the enormous amounts circulating throughout the body as a result of a SARS-CoV-2 infection.

My take is that children 6-months to 5-years-old deserve SARS-CoV-2–induced vaccine protection and we can and should strongly recommend it as medical providers and child advocates.
 

*Dr. Harrison is professor, University of Missouri Kansas City School of Medicine, department of medicine, infectious diseases section, Kansas City. Email him at pdnews@mdedge.com.

References

1. AAP. 2022 Jun 21. As COVID-19 vaccines become available for children ages 6 months to 4 years, AAP urges families to reach out to pediatricians to ask questions and access vaccine. www.aap.org.

2. CDC. Grading of recommendations, assessment, development, and evaluation (GRADE): Moderna COVID-19 vaccine for children aged 6 months–5 years. www.cdc.gov.

3. CDC. ACIP evidence to recommendations for use of Moderna COVID-19 vaccine in children ages 6 months–5 years and Pfizer-BioNTech COVID-19 vaccine in children ages 6 months–4 years under an emergency use authorization. www.cdc.gov.

4. Tang J et al. Nat Commun. 2022;13:2979.

5. Children and COVID-19: State Data Report. 2022 Jun 30. www.aap.org.

6. Shi DS et al. MMWR Morb Mortal Wkly Rep. 2022;71:574-81.

7. Marks KJ et al. MMWR Morb Mortal Wkly Rep. 2022;71:429-36.
 

Other good resources for families are https://getvaccineanswers.org/ or www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-in-babies-and-children/art-20484405.

*This story was updated on July 19, 2022.

In an online statement the U.S. Centers for Disease Control and Prevention announced its decision to recommend higher-dose and adjuvanted influenza vaccines for people aged 65 years or older. Fluzone High-Dose Quadrivalent, Flublok Quadrivalent, and Fluad Quadrivalent flu vaccines are among those specified in the release.

The organization says that these higher-dose vaccines may be more effective for the aging population, who often have difficulty mounting a strong enough immune response to protect themselves against the flu virus. People older than 65 years struggle the most during flu season and have the highest proportion of hospitalizations and deaths from flu, according to the release.

But the CDC believes that higher-dose vaccines have the potential to better protect against that danger. One study, from The New England Journal of Medicine, reported that high-dose/adjuvanted vaccines prevented flu in older patients 24% better than did lower-dose/nonadjuvanted vaccines.

These types of vaccines work by creating a larger immune response than a standard vaccine dose. In particular, adjuvanted vaccines contain an extra ingredient within them that helps the immune system produce a stronger reaction to the vaccine. These may be things like aluminum salts, which signal the body to respond faster. Higher-dose vaccines similarly promote a stronger immune response by having more particles of the target virus in their mixture. In theory, this means the body will create an enhanced response to the vaccine. For example, a higher-dose vaccine may quadruple the amount of antigens, compared with the standard dose.

The hope is that this recommendation may increase vaccine use across the board, says José Romero, MD, the director of the CDC’s National Center for Immunization and Respiratory Diseases. As quoted in the CDC announcement, Dr. Romero said that this may help reduce racial inequities in access to flu vaccines. A 2019 meta-analysis concluded that Black and Hispanic people are around 30%-40% less likely to get the flu vaccine. So increasing the access to this medication “could help reduce health disparities by making these vaccines more available to racial and ethnic minority groups,” said Dr. Romero.

The decision, spearheaded by CDC Director Rochelle Walensky, MD, follows recommendations from the Advisory Committee on Immunization Practices, which presented on this topic during a June 22 meeting. It is now part of official CDC policy and will continue to be developed as the 2022-2023 flu season approaches.

In addition, the organization says they’ll reveal more details for their plan later this summer, in their Morbidity and Mortality Weekly Report (MMWR). For now, seniors should know that they should try to get the recommended high-dose vaccines, but if they can’t, then a standard dose of whatever their provider has on hand will do.

At this point, there is still no specific vaccine recommendation for people aged under 65 years. The CDC historically avoids specifying one type of vaccine over another and says each should still be effective in younger patients.

A version of this article first appeared on Medscape.com.

In an online statement the U.S. Centers for Disease Control and Prevention announced its decision to recommend higher-dose and adjuvanted influenza vaccines for people aged 65 years or older. Fluzone High-Dose Quadrivalent, Flublok Quadrivalent, and Fluad Quadrivalent flu vaccines are among those specified in the release.

The organization says that these higher-dose vaccines may be more effective for the aging population, who often have difficulty mounting a strong enough immune response to protect themselves against the flu virus. People older than 65 years struggle the most during flu season and have the highest proportion of hospitalizations and deaths from flu, according to the release.

But the CDC believes that higher-dose vaccines have the potential to better protect against that danger. One study, from The New England Journal of Medicine, reported that high-dose/adjuvanted vaccines prevented flu in older patients 24% better than did lower-dose/nonadjuvanted vaccines.

These types of vaccines work by creating a larger immune response than a standard vaccine dose. In particular, adjuvanted vaccines contain an extra ingredient within them that helps the immune system produce a stronger reaction to the vaccine. These may be things like aluminum salts, which signal the body to respond faster. Higher-dose vaccines similarly promote a stronger immune response by having more particles of the target virus in their mixture. In theory, this means the body will create an enhanced response to the vaccine. For example, a higher-dose vaccine may quadruple the amount of antigens, compared with the standard dose.

The hope is that this recommendation may increase vaccine use across the board, says José Romero, MD, the director of the CDC’s National Center for Immunization and Respiratory Diseases. As quoted in the CDC announcement, Dr. Romero said that this may help reduce racial inequities in access to flu vaccines. A 2019 meta-analysis concluded that Black and Hispanic people are around 30%-40% less likely to get the flu vaccine. So increasing the access to this medication “could help reduce health disparities by making these vaccines more available to racial and ethnic minority groups,” said Dr. Romero.

The decision, spearheaded by CDC Director Rochelle Walensky, MD, follows recommendations from the Advisory Committee on Immunization Practices, which presented on this topic during a June 22 meeting. It is now part of official CDC policy and will continue to be developed as the 2022-2023 flu season approaches.

In addition, the organization says they’ll reveal more details for their plan later this summer, in their Morbidity and Mortality Weekly Report (MMWR). For now, seniors should know that they should try to get the recommended high-dose vaccines, but if they can’t, then a standard dose of whatever their provider has on hand will do.

At this point, there is still no specific vaccine recommendation for people aged under 65 years. The CDC historically avoids specifying one type of vaccine over another and says each should still be effective in younger patients.

A version of this article first appeared on Medscape.com.

In an online statement the U.S. Centers for Disease Control and Prevention announced its decision to recommend higher-dose and adjuvanted influenza vaccines for people aged 65 years or older. Fluzone High-Dose Quadrivalent, Flublok Quadrivalent, and Fluad Quadrivalent flu vaccines are among those specified in the release.

The organization says that these higher-dose vaccines may be more effective for the aging population, who often have difficulty mounting a strong enough immune response to protect themselves against the flu virus. People older than 65 years struggle the most during flu season and have the highest proportion of hospitalizations and deaths from flu, according to the release.

But the CDC believes that higher-dose vaccines have the potential to better protect against that danger. One study, from The New England Journal of Medicine, reported that high-dose/adjuvanted vaccines prevented flu in older patients 24% better than did lower-dose/nonadjuvanted vaccines.

These types of vaccines work by creating a larger immune response than a standard vaccine dose. In particular, adjuvanted vaccines contain an extra ingredient within them that helps the immune system produce a stronger reaction to the vaccine. These may be things like aluminum salts, which signal the body to respond faster. Higher-dose vaccines similarly promote a stronger immune response by having more particles of the target virus in their mixture. In theory, this means the body will create an enhanced response to the vaccine. For example, a higher-dose vaccine may quadruple the amount of antigens, compared with the standard dose.

The hope is that this recommendation may increase vaccine use across the board, says José Romero, MD, the director of the CDC’s National Center for Immunization and Respiratory Diseases. As quoted in the CDC announcement, Dr. Romero said that this may help reduce racial inequities in access to flu vaccines. A 2019 meta-analysis concluded that Black and Hispanic people are around 30%-40% less likely to get the flu vaccine. So increasing the access to this medication “could help reduce health disparities by making these vaccines more available to racial and ethnic minority groups,” said Dr. Romero.

The decision, spearheaded by CDC Director Rochelle Walensky, MD, follows recommendations from the Advisory Committee on Immunization Practices, which presented on this topic during a June 22 meeting. It is now part of official CDC policy and will continue to be developed as the 2022-2023 flu season approaches.

In addition, the organization says they’ll reveal more details for their plan later this summer, in their Morbidity and Mortality Weekly Report (MMWR). For now, seniors should know that they should try to get the recommended high-dose vaccines, but if they can’t, then a standard dose of whatever their provider has on hand will do.

At this point, there is still no specific vaccine recommendation for people aged under 65 years. The CDC historically avoids specifying one type of vaccine over another and says each should still be effective in younger patients.

A version of this article first appeared on Medscape.com.

In an April press release, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) reported the findings of their review concerning the efficacy of various dose schedules for human papillomavirus (HPV). “A single-dose HPV vaccine delivers solid protection against HPV, the virus that causes cervical cancer, that is comparable to 2-dose schedules,” according to SAGE.

This statement comes on the heels of an article published in the November 2021 issue of Lancet Oncology about a study in India. It found that a single dose of the vaccine provides protection against persistent infection from HPV 16 and 18 similar to that provided by two or three doses.

Will this new information lead French authorities to change their recommendations? What do French specialists think? At the 45th Congress of the French Society for Colposcopy and Cervical and Vaginal Diseases (SFCPCV), Geoffroy Canlorbe, MD, PhD, of the department of gynecologic and breast surgery and oncology, Pitié-Salpêtrière Hospital, Paris, shared his thoughts.

With respect to the Indian study, Dr. Canlorbe pointed out that while its findings would need “to be confirmed by other studies,” they were, nonetheless, “excellent news for developing countries where there are challenges when it comes to access to vaccination.”
 

India and France

During the congress press conference, he went on to say that, at this stage, the findings “cannot be extrapolated” to France. This is because the country’s situation is different. HPV vaccination coverage is low; estimates put it at 23.7%, placing the country 28th out of 31 in Europe.

“This poor coverage has nothing to do with health care–related logistical or organizational issues; instead, it has to do with people’s mistrust when it comes to vaccination. Here, people who get the first dose get the subsequent ones,” said Dr. Canlorbe. “The very fact of getting two to three doses allows the person’s body to increase the production of antibodies and get a longer-lasting response to the vaccine.”

In addition, he drew attention to several limitations of the Indian study. Initially, the team had planned to enroll 20,000 participants. In the end, there were around 17,000, and these were allocated to three cohorts: single-dose, two-dose, and three-dose. Furthermore, the primary objective, which had initially been focused on precancerous and cancerous lesions, was revised. The new aim was to compare vaccine efficacy of single dose to that of three and two doses in protecting against persistent HPV 16 and 18 infection at 10 years postvaccination. In about 90% of cases, the HPV infection went away spontaneously in 2 years without inducing lesions. Finally, the participants were women in India; therefore, the results cannot necessarily be generalized to the French population.

“This information has to be confirmed. However, as far as I know, there are no new studies going on at the moment. The Indian study, on the other hand, is still in progress,” said Dr. Canlorbe.

“In France, I think that for the time being we should stick to the studies that are currently available, which have demonstrated the efficacy and safety of two or three doses,” he concluded. In support of this approach, he cited a study on the effects of the national HPV vaccination program in England; there, the vaccination coverage is 80%.

This program was associated with a 95% risk reduction for precancerous lesions and an 87% reduction in the number of cancers, confirming the good results already achieved by Sweden and Australia.

In his comments on the WHO’s stance (which differs from that of the French experts), Jean-Luc Mergui, MD, gynecologist in the department of colposcopy and hysteroscopy at Pitié-Salpêtrière, and former president of the SFCPCV, offered an eloquent comparison: “The WHO also recommends 6 months of breastfeeding as a method of contraception, but this isn’t what’s recommended in France, for the risk of getting pregnant nevertheless remains.”
 

Indian study highlights

Partha Basu, MD, PhD, of the International Agency for Research on Cancer (IARC) in Lyon, France, and colleagues compared vaccine efficacy of a single dose of Gardasil (HPV 9-valent vaccine, recombinant) to that of two and three doses in protecting against persistent HPV 16 and HPV 18 infection at 10 years postvaccination.

According to the protocol, the plan was to recruit 20,000 unmarried girls, aged 10-18 years, from across India. Recruitment was initiated in September 2009. However, in response to seven unexplained deaths reported in another ongoing HPV vaccination demonstration program in the country, the Indian government issued a notification in April 2010 to stop further recruitment and HPV vaccination in all clinical trials. At this point, Dr. Basu and his team had recruited 17,729 eligible girls.

After suspension of recruitment and vaccination, their randomized trial was converted to a longitudinal, prospective, cohort study by default.

Vaccinated participants were followed up over a median duration of 9 years. In all, 4,348 participants had three doses, 4,980 had two doses (at 0 and 6 months), and 4,949 had a single dose. Cervical specimens were collected from participants 18 months after marriage or 6 months after first childbirth, whichever was earlier, to assess incident and persistent HPV infections. Participants were invited to an annual cervical cancer screening once they reached age 25 years and were married.

A single dose of HPV vaccine provides similar protection against persistent infection from HPV 16 and HPV 18, the genotypes responsible for nearly 70% of cervical cancers, compared with that provided by two or three doses. Vaccine efficacy against persistent HPV 16 and 18 infection among participants evaluable for the endpoint was 95.4% (95% confidence interval [CI], 85.0-99.9) in the single-dose default cohort (2,135 women assessed), 93.1% (95% CI, 77.3-99.8) in the two-dose cohort (1,452 women assessed), and 93.3% (95% CI, 77.5-99.7) in three-dose recipients (1,460 women assessed).

Dr. Canlorbe reported no relevant financial relationships regarding the content of this article.

This article was translated from the Medscape French edition. An English version appeared on Medscape.com.

In an April press release, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) reported the findings of their review concerning the efficacy of various dose schedules for human papillomavirus (HPV). “A single-dose HPV vaccine delivers solid protection against HPV, the virus that causes cervical cancer, that is comparable to 2-dose schedules,” according to SAGE.

This statement comes on the heels of an article published in the November 2021 issue of Lancet Oncology about a study in India. It found that a single dose of the vaccine provides protection against persistent infection from HPV 16 and 18 similar to that provided by two or three doses.

Will this new information lead French authorities to change their recommendations? What do French specialists think? At the 45th Congress of the French Society for Colposcopy and Cervical and Vaginal Diseases (SFCPCV), Geoffroy Canlorbe, MD, PhD, of the department of gynecologic and breast surgery and oncology, Pitié-Salpêtrière Hospital, Paris, shared his thoughts.

With respect to the Indian study, Dr. Canlorbe pointed out that while its findings would need “to be confirmed by other studies,” they were, nonetheless, “excellent news for developing countries where there are challenges when it comes to access to vaccination.”
 

India and France

During the congress press conference, he went on to say that, at this stage, the findings “cannot be extrapolated” to France. This is because the country’s situation is different. HPV vaccination coverage is low; estimates put it at 23.7%, placing the country 28th out of 31 in Europe.

“This poor coverage has nothing to do with health care–related logistical or organizational issues; instead, it has to do with people’s mistrust when it comes to vaccination. Here, people who get the first dose get the subsequent ones,” said Dr. Canlorbe. “The very fact of getting two to three doses allows the person’s body to increase the production of antibodies and get a longer-lasting response to the vaccine.”

In addition, he drew attention to several limitations of the Indian study. Initially, the team had planned to enroll 20,000 participants. In the end, there were around 17,000, and these were allocated to three cohorts: single-dose, two-dose, and three-dose. Furthermore, the primary objective, which had initially been focused on precancerous and cancerous lesions, was revised. The new aim was to compare vaccine efficacy of single dose to that of three and two doses in protecting against persistent HPV 16 and 18 infection at 10 years postvaccination. In about 90% of cases, the HPV infection went away spontaneously in 2 years without inducing lesions. Finally, the participants were women in India; therefore, the results cannot necessarily be generalized to the French population.

“This information has to be confirmed. However, as far as I know, there are no new studies going on at the moment. The Indian study, on the other hand, is still in progress,” said Dr. Canlorbe.

“In France, I think that for the time being we should stick to the studies that are currently available, which have demonstrated the efficacy and safety of two or three doses,” he concluded. In support of this approach, he cited a study on the effects of the national HPV vaccination program in England; there, the vaccination coverage is 80%.

This program was associated with a 95% risk reduction for precancerous lesions and an 87% reduction in the number of cancers, confirming the good results already achieved by Sweden and Australia.

In his comments on the WHO’s stance (which differs from that of the French experts), Jean-Luc Mergui, MD, gynecologist in the department of colposcopy and hysteroscopy at Pitié-Salpêtrière, and former president of the SFCPCV, offered an eloquent comparison: “The WHO also recommends 6 months of breastfeeding as a method of contraception, but this isn’t what’s recommended in France, for the risk of getting pregnant nevertheless remains.”
 

Indian study highlights

Partha Basu, MD, PhD, of the International Agency for Research on Cancer (IARC) in Lyon, France, and colleagues compared vaccine efficacy of a single dose of Gardasil (HPV 9-valent vaccine, recombinant) to that of two and three doses in protecting against persistent HPV 16 and HPV 18 infection at 10 years postvaccination.

According to the protocol, the plan was to recruit 20,000 unmarried girls, aged 10-18 years, from across India. Recruitment was initiated in September 2009. However, in response to seven unexplained deaths reported in another ongoing HPV vaccination demonstration program in the country, the Indian government issued a notification in April 2010 to stop further recruitment and HPV vaccination in all clinical trials. At this point, Dr. Basu and his team had recruited 17,729 eligible girls.

After suspension of recruitment and vaccination, their randomized trial was converted to a longitudinal, prospective, cohort study by default.

Vaccinated participants were followed up over a median duration of 9 years. In all, 4,348 participants had three doses, 4,980 had two doses (at 0 and 6 months), and 4,949 had a single dose. Cervical specimens were collected from participants 18 months after marriage or 6 months after first childbirth, whichever was earlier, to assess incident and persistent HPV infections. Participants were invited to an annual cervical cancer screening once they reached age 25 years and were married.

A single dose of HPV vaccine provides similar protection against persistent infection from HPV 16 and HPV 18, the genotypes responsible for nearly 70% of cervical cancers, compared with that provided by two or three doses. Vaccine efficacy against persistent HPV 16 and 18 infection among participants evaluable for the endpoint was 95.4% (95% confidence interval [CI], 85.0-99.9) in the single-dose default cohort (2,135 women assessed), 93.1% (95% CI, 77.3-99.8) in the two-dose cohort (1,452 women assessed), and 93.3% (95% CI, 77.5-99.7) in three-dose recipients (1,460 women assessed).

Dr. Canlorbe reported no relevant financial relationships regarding the content of this article.

This article was translated from the Medscape French edition. An English version appeared on Medscape.com.

In an April press release, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) reported the findings of their review concerning the efficacy of various dose schedules for human papillomavirus (HPV). “A single-dose HPV vaccine delivers solid protection against HPV, the virus that causes cervical cancer, that is comparable to 2-dose schedules,” according to SAGE.

This statement comes on the heels of an article published in the November 2021 issue of Lancet Oncology about a study in India. It found that a single dose of the vaccine provides protection against persistent infection from HPV 16 and 18 similar to that provided by two or three doses.

Will this new information lead French authorities to change their recommendations? What do French specialists think? At the 45th Congress of the French Society for Colposcopy and Cervical and Vaginal Diseases (SFCPCV), Geoffroy Canlorbe, MD, PhD, of the department of gynecologic and breast surgery and oncology, Pitié-Salpêtrière Hospital, Paris, shared his thoughts.

With respect to the Indian study, Dr. Canlorbe pointed out that while its findings would need “to be confirmed by other studies,” they were, nonetheless, “excellent news for developing countries where there are challenges when it comes to access to vaccination.”
 

India and France

During the congress press conference, he went on to say that, at this stage, the findings “cannot be extrapolated” to France. This is because the country’s situation is different. HPV vaccination coverage is low; estimates put it at 23.7%, placing the country 28th out of 31 in Europe.

“This poor coverage has nothing to do with health care–related logistical or organizational issues; instead, it has to do with people’s mistrust when it comes to vaccination. Here, people who get the first dose get the subsequent ones,” said Dr. Canlorbe. “The very fact of getting two to three doses allows the person’s body to increase the production of antibodies and get a longer-lasting response to the vaccine.”

In addition, he drew attention to several limitations of the Indian study. Initially, the team had planned to enroll 20,000 participants. In the end, there were around 17,000, and these were allocated to three cohorts: single-dose, two-dose, and three-dose. Furthermore, the primary objective, which had initially been focused on precancerous and cancerous lesions, was revised. The new aim was to compare vaccine efficacy of single dose to that of three and two doses in protecting against persistent HPV 16 and 18 infection at 10 years postvaccination. In about 90% of cases, the HPV infection went away spontaneously in 2 years without inducing lesions. Finally, the participants were women in India; therefore, the results cannot necessarily be generalized to the French population.

“This information has to be confirmed. However, as far as I know, there are no new studies going on at the moment. The Indian study, on the other hand, is still in progress,” said Dr. Canlorbe.

“In France, I think that for the time being we should stick to the studies that are currently available, which have demonstrated the efficacy and safety of two or three doses,” he concluded. In support of this approach, he cited a study on the effects of the national HPV vaccination program in England; there, the vaccination coverage is 80%.

This program was associated with a 95% risk reduction for precancerous lesions and an 87% reduction in the number of cancers, confirming the good results already achieved by Sweden and Australia.

In his comments on the WHO’s stance (which differs from that of the French experts), Jean-Luc Mergui, MD, gynecologist in the department of colposcopy and hysteroscopy at Pitié-Salpêtrière, and former president of the SFCPCV, offered an eloquent comparison: “The WHO also recommends 6 months of breastfeeding as a method of contraception, but this isn’t what’s recommended in France, for the risk of getting pregnant nevertheless remains.”
 

Indian study highlights

Partha Basu, MD, PhD, of the International Agency for Research on Cancer (IARC) in Lyon, France, and colleagues compared vaccine efficacy of a single dose of Gardasil (HPV 9-valent vaccine, recombinant) to that of two and three doses in protecting against persistent HPV 16 and HPV 18 infection at 10 years postvaccination.

According to the protocol, the plan was to recruit 20,000 unmarried girls, aged 10-18 years, from across India. Recruitment was initiated in September 2009. However, in response to seven unexplained deaths reported in another ongoing HPV vaccination demonstration program in the country, the Indian government issued a notification in April 2010 to stop further recruitment and HPV vaccination in all clinical trials. At this point, Dr. Basu and his team had recruited 17,729 eligible girls.

After suspension of recruitment and vaccination, their randomized trial was converted to a longitudinal, prospective, cohort study by default.

Vaccinated participants were followed up over a median duration of 9 years. In all, 4,348 participants had three doses, 4,980 had two doses (at 0 and 6 months), and 4,949 had a single dose. Cervical specimens were collected from participants 18 months after marriage or 6 months after first childbirth, whichever was earlier, to assess incident and persistent HPV infections. Participants were invited to an annual cervical cancer screening once they reached age 25 years and were married.

A single dose of HPV vaccine provides similar protection against persistent infection from HPV 16 and HPV 18, the genotypes responsible for nearly 70% of cervical cancers, compared with that provided by two or three doses. Vaccine efficacy against persistent HPV 16 and 18 infection among participants evaluable for the endpoint was 95.4% (95% confidence interval [CI], 85.0-99.9) in the single-dose default cohort (2,135 women assessed), 93.1% (95% CI, 77.3-99.8) in the two-dose cohort (1,452 women assessed), and 93.3% (95% CI, 77.5-99.7) in three-dose recipients (1,460 women assessed).

Dr. Canlorbe reported no relevant financial relationships regarding the content of this article.

This article was translated from the Medscape French edition. An English version appeared on Medscape.com.

A new Scandinavian study has confirmed previous data showing increased rates of cerebral venous thrombosis and thrombocytopenia after the AstraZeneca COVID-19 vaccine.

The study also showed higher rates of several thromboembolic and thrombocytopenic outcomes after the Pfizer and Moderna mRNA vaccines, although these increases were less than the rates observed after the AstraZeneca vaccine, and sensitivity analyses were not consistent.

The researchers conclude that confirmatory analysis on the two mRNA vaccines by other methods are warranted.

The study was published in the June issue of JAMA Network Open.

“This study confirms what we know from other studies: that the AstraZeneca vaccine is associated with the rare but serious side effect of vaccine-induced immune thrombotic thrombocytopenia,” lead author Jacob Dag Berild, MD, Norwegian Institute of Public Health, Oslo, told this news organization.

“Reassuringly, no consistent association was observed between the Pfizer and Moderna mRNA vaccines and these rare complications,” he added.

Dr. Dag Berild noted that in the current study there was an excess of 1.6 events of cerebral venous thrombosis per 100,000 AstraZeneca vaccine doses, which is similar to what has been previously reported.

Asked how he saw these results affecting continued use of these vaccines, Dr. Dag Berild pointed out that the risk-benefit ratio of the vaccine depends on the risk of contracting COVID-19 and the risk for a severe outcome from COVID-19 weighed against the risk for an adverse event after vaccination.

“The European Medicines Agency has concluded that the overall risk-benefit ratio remains positive for the AstraZeneca vaccine, but Norway, Finland, and Denmark no longer use the AstraZeneca vaccine in their vaccination programs because of adequate availability of alternative vaccines. I think this is a reasonable decision,” he said.

For the current study, the researchers linked individual-level data separately from national population, patient, and vaccination registers in Norway, Finland, and Denmark. Patient registers were used to identify hospital visits and admissions related to thromboembolic and thrombocytopenic disease in all three countries.

The main outcomes were relative rates of coronary artery disease, coagulation disorders, and cerebrovascular disease in the 28-day period after vaccination, compared with the control period prior to vaccination.

The authors note that a strength of this study is the use of registers with full population coverage in three countries with universal health care, ensuring equal access to care for all permanent residents. At the end of the study period, from Jan. 1, 2020 to May 16, 2021, more than 5.3 million people in the three countries were vaccinated with one or two doses.

Another strength is the inherent adjustment for time-invariant confounders in the self-controlled case series design and the resulting control of confounders that can affect the more traditional observational studies when complete data for confounders are not available, they add.

Of the 265,339 hospital contacts, 43% were made by female patients and 93% by patients born in or before 1971, and 44% were for coronary artery disease, 21% for coagulation disorders, and 35% for cerebrovascular disease.

In the 28-day period after vaccination, there was an elevated rate of coronary artery disease after the Moderna vaccine (relative rate, 1.13) but not after the AstraZeneca (RR, 0.92) or Pfizer (RR, 0.96) vaccines.

There was an observed increase in the rate of coagulation disorders after all three vaccines (AstraZeneca RR, 2.01; Pfizer RR, 1.12; and Moderna RR, 1.26).

There was also an increase in the rate of cerebrovascular disease after all three vaccines (AstraZeneca RR, 1.32; Pfizer RR, 1.09; and Moderna RR, 1.21).

For individual diseases in the main outcomes, two notably high rates were observed after the AstraZeneca vaccine, with relative rates of 12.04 for cerebral venous thrombosis and 4.29 for thrombocytopenia, corresponding to 1.6 and 4.9 excess events per 100,000 doses, respectively.

The elevated risk after the AstraZeneca vaccine was consistent across all three countries and robust in sensitivity analyses.

The researchers report that they also observed statistically significant increases in hospital contacts for thrombocytopenic and thromboembolic events after the Pfizer and Moderna vaccines. However, the risk was smaller than after the AstraZeneca vaccine.

“Additionally, the national estimates varied, increased risk [was] observed only in the oldest cohorts, and sensitivity analysis checking underlying assumptions of the analyses were not consistent. Therefore, the overall and combined increased relative risks following the Pfizer and Moderna vaccinations should be interpreted with caution,” they say.

They note that their results with the AstraZeneca vaccine are in line with a comparison of observed and historic rates performed on partly the same population in Norway and Denmark and also with a Scottish national case-control study.

A version of this article first appeared on Medscape.com.

A new Scandinavian study has confirmed previous data showing increased rates of cerebral venous thrombosis and thrombocytopenia after the AstraZeneca COVID-19 vaccine.

The study also showed higher rates of several thromboembolic and thrombocytopenic outcomes after the Pfizer and Moderna mRNA vaccines, although these increases were less than the rates observed after the AstraZeneca vaccine, and sensitivity analyses were not consistent.

The researchers conclude that confirmatory analysis on the two mRNA vaccines by other methods are warranted.

The study was published in the June issue of JAMA Network Open.

“This study confirms what we know from other studies: that the AstraZeneca vaccine is associated with the rare but serious side effect of vaccine-induced immune thrombotic thrombocytopenia,” lead author Jacob Dag Berild, MD, Norwegian Institute of Public Health, Oslo, told this news organization.

“Reassuringly, no consistent association was observed between the Pfizer and Moderna mRNA vaccines and these rare complications,” he added.

Dr. Dag Berild noted that in the current study there was an excess of 1.6 events of cerebral venous thrombosis per 100,000 AstraZeneca vaccine doses, which is similar to what has been previously reported.

Asked how he saw these results affecting continued use of these vaccines, Dr. Dag Berild pointed out that the risk-benefit ratio of the vaccine depends on the risk of contracting COVID-19 and the risk for a severe outcome from COVID-19 weighed against the risk for an adverse event after vaccination.

“The European Medicines Agency has concluded that the overall risk-benefit ratio remains positive for the AstraZeneca vaccine, but Norway, Finland, and Denmark no longer use the AstraZeneca vaccine in their vaccination programs because of adequate availability of alternative vaccines. I think this is a reasonable decision,” he said.

For the current study, the researchers linked individual-level data separately from national population, patient, and vaccination registers in Norway, Finland, and Denmark. Patient registers were used to identify hospital visits and admissions related to thromboembolic and thrombocytopenic disease in all three countries.

The main outcomes were relative rates of coronary artery disease, coagulation disorders, and cerebrovascular disease in the 28-day period after vaccination, compared with the control period prior to vaccination.

The authors note that a strength of this study is the use of registers with full population coverage in three countries with universal health care, ensuring equal access to care for all permanent residents. At the end of the study period, from Jan. 1, 2020 to May 16, 2021, more than 5.3 million people in the three countries were vaccinated with one or two doses.

Another strength is the inherent adjustment for time-invariant confounders in the self-controlled case series design and the resulting control of confounders that can affect the more traditional observational studies when complete data for confounders are not available, they add.

Of the 265,339 hospital contacts, 43% were made by female patients and 93% by patients born in or before 1971, and 44% were for coronary artery disease, 21% for coagulation disorders, and 35% for cerebrovascular disease.

In the 28-day period after vaccination, there was an elevated rate of coronary artery disease after the Moderna vaccine (relative rate, 1.13) but not after the AstraZeneca (RR, 0.92) or Pfizer (RR, 0.96) vaccines.

There was an observed increase in the rate of coagulation disorders after all three vaccines (AstraZeneca RR, 2.01; Pfizer RR, 1.12; and Moderna RR, 1.26).

There was also an increase in the rate of cerebrovascular disease after all three vaccines (AstraZeneca RR, 1.32; Pfizer RR, 1.09; and Moderna RR, 1.21).

For individual diseases in the main outcomes, two notably high rates were observed after the AstraZeneca vaccine, with relative rates of 12.04 for cerebral venous thrombosis and 4.29 for thrombocytopenia, corresponding to 1.6 and 4.9 excess events per 100,000 doses, respectively.

The elevated risk after the AstraZeneca vaccine was consistent across all three countries and robust in sensitivity analyses.

The researchers report that they also observed statistically significant increases in hospital contacts for thrombocytopenic and thromboembolic events after the Pfizer and Moderna vaccines. However, the risk was smaller than after the AstraZeneca vaccine.

“Additionally, the national estimates varied, increased risk [was] observed only in the oldest cohorts, and sensitivity analysis checking underlying assumptions of the analyses were not consistent. Therefore, the overall and combined increased relative risks following the Pfizer and Moderna vaccinations should be interpreted with caution,” they say.

They note that their results with the AstraZeneca vaccine are in line with a comparison of observed and historic rates performed on partly the same population in Norway and Denmark and also with a Scottish national case-control study.

A version of this article first appeared on Medscape.com.

A new Scandinavian study has confirmed previous data showing increased rates of cerebral venous thrombosis and thrombocytopenia after the AstraZeneca COVID-19 vaccine.

The study also showed higher rates of several thromboembolic and thrombocytopenic outcomes after the Pfizer and Moderna mRNA vaccines, although these increases were less than the rates observed after the AstraZeneca vaccine, and sensitivity analyses were not consistent.

The researchers conclude that confirmatory analysis on the two mRNA vaccines by other methods are warranted.

The study was published in the June issue of JAMA Network Open.

“This study confirms what we know from other studies: that the AstraZeneca vaccine is associated with the rare but serious side effect of vaccine-induced immune thrombotic thrombocytopenia,” lead author Jacob Dag Berild, MD, Norwegian Institute of Public Health, Oslo, told this news organization.

“Reassuringly, no consistent association was observed between the Pfizer and Moderna mRNA vaccines and these rare complications,” he added.

Dr. Dag Berild noted that in the current study there was an excess of 1.6 events of cerebral venous thrombosis per 100,000 AstraZeneca vaccine doses, which is similar to what has been previously reported.

Asked how he saw these results affecting continued use of these vaccines, Dr. Dag Berild pointed out that the risk-benefit ratio of the vaccine depends on the risk of contracting COVID-19 and the risk for a severe outcome from COVID-19 weighed against the risk for an adverse event after vaccination.

“The European Medicines Agency has concluded that the overall risk-benefit ratio remains positive for the AstraZeneca vaccine, but Norway, Finland, and Denmark no longer use the AstraZeneca vaccine in their vaccination programs because of adequate availability of alternative vaccines. I think this is a reasonable decision,” he said.

For the current study, the researchers linked individual-level data separately from national population, patient, and vaccination registers in Norway, Finland, and Denmark. Patient registers were used to identify hospital visits and admissions related to thromboembolic and thrombocytopenic disease in all three countries.

The main outcomes were relative rates of coronary artery disease, coagulation disorders, and cerebrovascular disease in the 28-day period after vaccination, compared with the control period prior to vaccination.

The authors note that a strength of this study is the use of registers with full population coverage in three countries with universal health care, ensuring equal access to care for all permanent residents. At the end of the study period, from Jan. 1, 2020 to May 16, 2021, more than 5.3 million people in the three countries were vaccinated with one or two doses.

Another strength is the inherent adjustment for time-invariant confounders in the self-controlled case series design and the resulting control of confounders that can affect the more traditional observational studies when complete data for confounders are not available, they add.

Of the 265,339 hospital contacts, 43% were made by female patients and 93% by patients born in or before 1971, and 44% were for coronary artery disease, 21% for coagulation disorders, and 35% for cerebrovascular disease.

In the 28-day period after vaccination, there was an elevated rate of coronary artery disease after the Moderna vaccine (relative rate, 1.13) but not after the AstraZeneca (RR, 0.92) or Pfizer (RR, 0.96) vaccines.

There was an observed increase in the rate of coagulation disorders after all three vaccines (AstraZeneca RR, 2.01; Pfizer RR, 1.12; and Moderna RR, 1.26).

There was also an increase in the rate of cerebrovascular disease after all three vaccines (AstraZeneca RR, 1.32; Pfizer RR, 1.09; and Moderna RR, 1.21).

For individual diseases in the main outcomes, two notably high rates were observed after the AstraZeneca vaccine, with relative rates of 12.04 for cerebral venous thrombosis and 4.29 for thrombocytopenia, corresponding to 1.6 and 4.9 excess events per 100,000 doses, respectively.

The elevated risk after the AstraZeneca vaccine was consistent across all three countries and robust in sensitivity analyses.

The researchers report that they also observed statistically significant increases in hospital contacts for thrombocytopenic and thromboembolic events after the Pfizer and Moderna vaccines. However, the risk was smaller than after the AstraZeneca vaccine.

“Additionally, the national estimates varied, increased risk [was] observed only in the oldest cohorts, and sensitivity analysis checking underlying assumptions of the analyses were not consistent. Therefore, the overall and combined increased relative risks following the Pfizer and Moderna vaccinations should be interpreted with caution,” they say.

They note that their results with the AstraZeneca vaccine are in line with a comparison of observed and historic rates performed on partly the same population in Norway and Denmark and also with a Scottish national case-control study.

A version of this article first appeared on Medscape.com.