, even though many top infectious disease experts questioned the need before the agency’s decision.
The FDA granted emergency use authorization for both Pfizer and Moderna to offer the second booster – and fourth shot overall – for adults over 50 as well as those over 18 with compromised immune systems.
The Centers for Control and Prevention must still sign off before those doses start reaching American arms. That approval could come at any time.
“The general consensus, certainly the CDC’s consensus, is that the current vaccines are still really quite effective against Omicron and this new BA.2 variant in keeping people out of the hospital, and preventing the development of severe disease,” William Schaffner, MD, an infectious disease specialist at Vanderbilt University in Nashville said prior to the FDA’s announcement March 29.
Of the 217.4 million Americans who are “fully vaccinated,” i.e., received two doses of either Pfizer or Moderna’s vaccines or one dose of the Johnson & Johnson vaccine, only 45% have also received a booster shot, according to the CDC.
“Given that, there’s no need at the moment for the general population to get a fourth inoculation,” Dr. Schaffner says. “Our current focus ought to be on making sure that as many people as possible get that [first] booster who are eligible.”
Monica Gandhi, MD, an infectious disease specialist at the University of California, San Francisco, agreed that another booster for everyone was unnecessary. The only people who would need a fourth shot (or third, if they had the Johnson & Johnson vaccine initially) are those over age 65 or 70 years, Dr. Gandhi says.
“Older people need those antibodies up high because they’re more susceptible to severe breakthroughs,” she said, also before the latest development.
To boost or not to boost
Daniel Kuritzkes, MD, chief of infectious diseases at Brigham & Women’s Hospital in Boston, said the timing of a booster and who should be eligible depends on what the nation is trying to achieve with its vaccination strategy.
“Is the goal to prevent any symptomatic infection with COVID-19, is the goal to prevent the spread of COVID-19, or is the goal to prevent severe disease that requires hospitalization?” asked Dr. Kuritzkes.
The current vaccine — with a booster — has prevented severe disease, he said.
An Israeli study showed, for instance, that a third Pfizer dose was 93% effective against hospitalization, 92% effective against severe illness, and 81% effective against death.
A just-published study in the New England Journal of Medicine found that a booster of the Pfizer vaccine was 95% effective against COVID-19 infection and that it did not raise any new safety issues.
A small Israeli study, also published in NEJM, of a fourth Pfizer dose given to health care workers found that it prevented symptomatic infection and illness, but that it was much less effective than previous doses — maybe 65% effective against symptomatic illness, the authors write.
Giving Americans another booster now — which has been shown to lose some effectiveness after about 4 months — means it might not offer protection this fall and winter, when there could be a seasonal surge of the virus, Dr. Kuritzkes says.
And, even if people receive boosters every few months, they are still likely to get a mild respiratory virus infection, he said.
“I’m pretty convinced that we cannot boost ourselves out of this pandemic,” said Dr. Kuritzkes. “We need to first of all ensure there’s global immunization so that all the people who have not been vaccinated at all get vaccinated. That’s far more important than boosting people a fourth time.”