Scientists at the Food and Drug Administration (FDA) said Wednesday Pfizer’s Covid-19 vaccine seems to last long enough that a booster shot may not add much protection, according to documents the agency released Wednesday, previewing skepticism the company may face when an advisory committee meets Friday to discuss whether a third dose should be approved.
In its briefing document for the advisory committee, Pfizer—which wants a third dose approved for people ages 16 and up—said that studies show its vaccine’s odds of protecting against Covid-19 infection falls from 96% in the weeks following a second shot to 84% after four months, while a booster dose brings protection back up to 95%, even against the delta variant dominant in the U.S. and in much of the world.
FDA scientists wrote in their own briefing document that while studies have differed on whether the Pfizer vaccine eventually loses some power to protect against Covid-19 infections, most data show that the original shots continue to protect strongly against severe infections that could put someone in the hospital.
The scientists, who do not vote themselves on whether to approve the booster, wrote that if the two shots continue to largely prevent against the worst effects of Covid, a booster’s benefits are “likely to be more limited.”
Pfizer’s case may also be challenged Friday in a presentation by Marion Gruber, the head of Vaccines Research and Overview at the FDA, who announced her resignation in August reportedly over the push for booster shots by President Joe Biden—and who co-authored research published Monday that found there is no scientific basis for booster shots.
The Biden administration announced in mid-August that it would be ready on September 20 to start giving booster shots to people who had received their second dose eight months earlier—pending approval from the FDA and CDC, whose leaders are presidential appointments but who generally follow the recommendations of expert committees that meet regularly to decide on vaccinations. In early September, news that Moderna would not be ready for its booster doses to be approved on Friday—it needed to collect more data—brought up a new obstacle for President Joe Biden’s strategy to stamp out the pandemic, which includes rolling out additional doses.
What To Watch For
If the FDA’s advisory committee approves Pfizer’s submission on Friday, the agency’s leader could provide the final sign-off within a couple of days, according to a source familiar with the approval process. For the booster to have the full blessing of federal health agencies, the CDC’s advisory committee—which recommends vaccine policies for healthcare providers—needs to sign off, and their next meeting is September 29.
Booster doses are not needed for most people, according to research published Monday in the Lancet, a British medical journal. While Covid-19 vaccines do lose some ability over time to prevent mild cases, the authors—including Gruber of the FDA—found that they continue to offer very strong protection against severe cases, including against the delta variant. They wrote that advocating for booster doses can erode confidence in the vaccine, making unvaccinated people less likely to get the shot.
Scientific Evidence Doesn’t Back Booster Covid Shots, Researchers Warn — Even For The Delta Variant (Forbes)
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