Data For Newly Authorized COVID-19 Boosters Based On Mice, Not Humans

According to a presentation that will be given to the advisory panel of the CDC by Pfizer scientists, the data for the newly authorised COVID-19 boosters is based on mice, not humans.

Data For Newly Authorized COVID-19 Boosters Based On Mice, Not Humans 1

Because U.S. officials feel that waiting for human trial data would have rendered the revised boosters obsolete, the preclinical data for the recently permitted COVID-19 booster doses is only based on mice, not people.

In June, Pfizer scientists informed the FDA vaccine advisory council that the data for their booster vaccination was based on only 8 mice. According to a presentation that will be given to the advisory panel of the U.S. Centers for Disease Control and Prevention (CDC) on September 1, the data for Moderna’s booster was based on 16 to 20 mice, some of which received the original booster.

According to Kena Swanson, vice president of Pfizer’s vaccine research and development, the mouse data reveal “substantial increases against all Omicron sublineages including BA.4/5 as well as the reference strain with the BA.4/5- modified vaccines.”

Both BA.4 and BA.5 are subvariants of the COVID-19-causing Omicron variant of the virus.

Both Moderna and Pfizer created boosters that included elements of the original COVID-19 virus and the BA.1 subvariant; however, the FDA requested that the vaccine producers replace the BA.1 component with an element that targets BA.4 and BA.5, the latter of which is the predominant strain in the United States, following the June meeting.

On August 31, the FDA authorised both revised boosters after choosing not to request human trial data.

Dr. Peter Marks, a top FDA vaccine expert, told reporters on a call that the mice data “demonstrate that these vaccines successfully evoke an immune response in the same way previous versions of the vaccine have.”

Dr. Rochelle Walensky, director of the CDC, also expressed support for the course.

In a discussion that aired on “Conversations on Health Care” on August 29, Walensky stated, “If we wait for those data to emerge in human data, not just mice data, we will be using what I would consider to be a potentially outdated vaccine.”


The updated booster, according to Dr. Monica Gandhi, a professor of medicine at the University of California, San Francisco, “has the potential to increase antibodies in humans to the circulating subvariant (mainly BA.5 at this point) but to be fair, we need to note that we only have data in mice of increased antibodies at this point.”

“We do not have human data on this new booster, either antibody data or clinical data. However, there is biological plausibility that these updated boosters will curb cases by increasing antibodies as we enter the winter,” Gandhi said in an email.

Gandhi, citing current studies (pdf below) on vaccine effectiveness, advises all Americans 65 years of age and older, as well as those who are immunocompromised, to obtain the updated booster injection, particularly in those whose most recent shot was given more than six months ago.

Just two months after receiving their most recent vaccine, the FDA is recommended all Americans aged 12 and older to receive the current booster.

Prior to the authorizations, John Moore, a vaccine expert at Weill Cornell Medicine, told USA Today that relying on mice data “would be unprecedented in my knowledge and would certainly raise eyebrows.” However, on Thursday, Moore said that he is not worried about safety.

“It’s still the same vaccine, just with a small tweak. The same strategy is used every year to adjust the composition of the standard flu vaccines. I’d draw an analogy to getting a new paint job on your car—that would not trigger the need for a full-service check into all the safety features. However, I think many members of the public may be concerned—particularly ones who have listened to the lies from anti-vaxxers,” he added, using a pejorative for people concerned about vaccine side effects and waning effectiveness.

Trial data is available for the boosters containing BA.1. According to the statistics, the boosters performed better than the current boosters, which just targeted the original virus type.

Early on in the pandemic, that variant was displaced. Since then, a number of variations have appeared. In the latter half of 2021, Omicron consolidated its power in the US. The strain and its subvariants have demonstrated a greater capacity to circumvent the immunity conferred by vaccines, leading to the clearance and recommendation of boosters and, more recently, the authorization of the updated boosters.

The CDC met with its advisory council on Thursday to discuss whether it should urge patients to get an updated booster shot or just suggest it.

Read the study given below:


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