FDA's Vaccines and Related Biological Products Advisory Committee on Friday voted 16-2 against recommending booster shots of the Pfizer-BioNTech Covid-19 vaccine to all adults 16 and older six months after full vaccination, but unanimously voted to recommend the shots to adults 65 and older and those at high risk for severe Covid-19.
In August, the Biden administration announced that it intended to make booster shots available for all Americans who received an mRNA vaccine eight months after their second shot beginning the week of Sept. 20, pending FDA authorization and CDC recommendation.
The FDA committee's recommendation is narrower, however, and would not include boosters for most people under the age of 65.
FDA is expected to make a decision regarding booster shots in coming days, the New York Times reports, and is not required to follow the recommendation of the advisory panel.
In a statement following the FDA panel's vote, Kathrin Jansen, head of vaccine research and development for Pfizer, said the company "will work with the FDA … to address the committee's questions, as we continue to believe in the benefits of a booster dose for the broader population."
At the meeting, members of the advisory committee—which consisted of vaccine experts, immunologists, pediatricians, infectious disease specialists, and public health experts—debated whether available data suggests booster shots should be available for everyone over the age of 16.
William Gruber, SVP of vaccine clinical research and development at Pfizer, said that multiple studies show people's immunity to the coronavirus wanes over time. "Israel and the United States real-world evidence suggests that vaccine efficacy against Covid-19 infection wanes approximately six to eight months following the second dose," he said.
According to Gruber, Pfizer's data shows booster shots restore and even enhance immunity and that they don't carry any worse side effects than the initial, two-dose regiment.
However, Phil Krause, deputy director of FDA's Office of Vaccines Research and Review, noted that Pfizer's data has not been peer-reviewed. "One of the issues in this is that much of the data that's been presented and being discussed today is not peer-reviewed and has not been reviewed by FDA," Krause said.
The data in Israel also was focused on adults age 60 and over, who were the first group made eligible to receive boosters in the country. As such, many members of the FDA committee doubted that the data supported booster shots for younger U.S. populations.
And Michael Kurilla, an infectious disease specialist at the National Center for Advancing Translational Sciences, said that Pfizer's data heavily relies on antibody measurements without looking at other elements of the immune response.
"It's a little disappointing that there's been very little reporting of the cellular immune responses and an entire focus on the neutralizing antisera," Kurilla said. "Which clearly for that population at high risk is absolutely essential, but for the broad population in terms of their protection, which seems to be holding up well over time—[that] should be because of adequate cellular immune responses but we have no indication of that."
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said he believes the Biden administration's plan announced in August lines up with the advisory panel's recommendation and that the "proper regimen" for mRNA shots will eventually include two shots and a booster.
"You want to do that according to what the data tells you, including the risk-benefit ratio, particularly for the younger people who do not generally get as much severe disease as the elderly and others," Fauci said. "So, I believe that there's a good chance that as we get into the coming months, into the next year, that you will see the data pointing to the benefit of having a much broader blanket of people."
Data on booster shots for the Covid-19 vaccines made by Moderna and Johnson & Johnson are also "literally a couple to a few weeks away," Fauci added.
Fauci advised Americans to exercise patience and wait until they're eligible to get a booster shot.
NIH Director Francis Collins said he'd be surprised if booster shots aren't made available for the general population, despite the FDA panel's recommendation.
"I think the big news is that they actually did approve the initiation of boosters, and, remember, they're taking a snapshot of right now. We're going to see what happens in the coming weeks," Collins said. "It would surprise me if it does not become clear over the next few weeks that administration of boosters may need to be enlarged."
Collins added he's unsure whether booster shots will be needed by "absolutely everyone," but said he'd be "surprised" if booster shots aren't recommended for those under 65 in the coming weeks. (Fox et al., CNN, 9/18; Thomas, New York Times, 9/20; Gardner, Politico, 9/17; Choi, The Hill, 9/19; Owens, Axios, 9/20; Crummy, Politico, 9/19; Beals, The Hill, 9/19)
The FDA committee's rejection of recommending boosters for all eligible U.S. citizens comes at a contentious point in the pandemic.
Although a new head-to-head study found that all authorized vaccines are highly protective in preventing hospitalizations, ongoing studies showing the slight waning of efficacy overall raises the question: as cases and hospitalizations continue to rise (particularly in those unvaccinated) are booster shots necessary—and for whom?
As we await the FDA's official decision, there are six questions we're watching that will determine the future of the boosters in the United States:
The FDA typically follows the advisory committee's recommendations when making official approval or authorization decisions (even though the committee's decision is not binding). However, given President Biden's highly publicized booster campaign—which was expected to take off just this week—it is unclear whether FDA will follow the recommendations. Further, this situation highlights the growing tension between the administration and scientists in controlling the pandemic.
During last week's meeting, scientists cited the lack of robust data on younger age groups (under the age of 65) as a key driver not recommending the vaccine for all people over the age of 12. To better understand safety and efficacy in all age groups, more robust data collection is necessary. However, FDA and CDC have yet to set or enforce any directives to collect this data to support expanded authorization. Whether Pfizer, regulators, providers, or other stakeholders are responsible remains to be determined.
Politico reported that a CDC panel is meeting this week "to outline the parameters for the booster's administration, which will likely include defining who qualifies as 'high risk.'" However, the definition of "high risk" is unclear, especially given the confusion and debate during the initial vaccine rollout about who qualified as "high risk," and lack of data demonstrating Covid-19's impact on various "high risk" groups. With excess supply of vaccines in the United States today, providers may be left to interpret the "high risk" definition on their own, complicating booster rollout.
Dr. Anthony Fauci just said in an interview with NBC that data on boosters from Moderna and J&J is "literally a couple to a few weeks away." What that data looks like, how it differs from the data on Pfizer's vaccine, and whether it provides answers to questions like vaccine efficacy in different demographics and high-risk groups, may determine future booster authorizations.
Scientists, researchers, doctors, and other health care professionals are debating the decision and the complex science behind it in the public eye, which is creating confusion for the public. Amidst ongoing misinformation about vaccines and Covid-19, health care leaders should discern what debates to share publicly versus what to keep in private to prevent the rise of confusion and misinformation/disinformation about boosters.
We'll keep watching for answers to these questions, but one thing is clear: the debate for boosters highlights the dire need for more data collection and coordination in the United States.
One major argument that scientists made against recommending boosters in the United States is that the real-world evidence from Israel doesn't necessarily apply to the United States, given the United States' more heterogeneous population than Israel. Additionally, the United States and Israel define severe illness differently, which can skew the data and make it hard to interpret. Regulators, manufacturers, and providers must invest in more proactive data tracking capabilities to better understand Covid-19 vaccine effectiveness in the United States.
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