Why some infectious disease docs are ‘encouraged’ by new bivalent COVID vaccines


A panel of infectious disease experts shared their take recently on the importance of the newly approved bivalent COVID-19 vaccines, why authorization without human data is not for them a cause for alarm, and what they are most optimistic about at this stage of the pandemic.

“I’m very encouraged by this new development,” Kathryn M. Edwards, MD, said during a media briefing sponsored by the Infectious Diseases Society of America (IDSA).

It makes sense to develop a vaccine that targets both the original SARS-CoV-2 strain and Omicron BA.4 and BA.5, she said. “It does seem that if you have a circulating strain BA.4 and BA.5, hitting it with the appropriate vaccine targeted for that is most immunogenic, certainly. We will hopefully see that in terms of effectiveness.”

Changing the vaccines at this point is appropriate, Walter A. Orenstein, MD, said. “One of our challenges is that this virus mutates. Our immune response is focused on an area of the virus that can change and be evaded,” said Dr. Orenstein, professor and associate director of the Emory Vaccine Center at Emory University, Atlanta.

“This is different than measles or polio,” he said. “But for influenza and now with SARS-CoV-2 ... we have to update our vaccines, because the virus changes.”

Man versus mouse

Dr. Edwards addressed the controversy over a lack of human data specific to these next-generation Pfizer/BioNTech and Moderna vaccines. “I do not want people to be unhappy or worried that the bivalent vaccine will act in a different way than the ones that we have been administering for the past 2 years.”

The Food and Drug Administration emergency use authorization may have relied primarily on animal studies, she said, but mice given a vaccine specific to BA.4 and BA.5 “have a much more robust immune response,” compared with those given a BA.1 vaccine.

Also, “over and over and over again we have seen with these SARS-CoV-2 vaccines that the mouse responses mirror the human responses,” said Dr. Edwards, scientific director of the Vanderbilt Vaccine Research Program at Vanderbilt University, Nashville, Tenn., and an IDSA fellow.

“Human data will be coming very soon to look at the immunogenicity,” she said.

A ‘glass half full’ perspective

When asked what they are most optimistic about at this point in the COVID-19 pandemic, Dr. Orenstein said, “I’m really positive in the sense that the vaccines we have are already very effective against severe disease, death, and hospitalization. I feel really good about that. And we have great tools.

“The bottom line for me is, I want to get it myself,” he said regarding the bivalent vaccine.

“There are a lot of things to be happy with,” Dr. Edwards said. “I’m kind of a glass-half-full kind of person.”

Dr. Edwards is confident that the surveillance systems now in place can accurately detect major changes in the virus, including new variants. She is also optimistic about the mRNA technology that allows rapid updates to COVID-19 vaccines.

Furthermore, “I’m happy that we’re beginning to open up – that we can go do different things that we have done in the past and feel much more comfortable,” she said.


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