- An expert panel recommended that the FDA authorize booster shots for older and vulnerable adults.
- The doctors and health experts who advise the FDA say data suggests younger people are still well protected.
- The panel voted down a proposal to make boosters available to everyone 16 and older.
- See more stories on Insider's business page.
An expert panel advising the US Food and Drug Administration said on Friday that a booster shot of Pfizer's coronavirus vaccine should be made available to older adults and others at high risk from the pandemic, under an emergency use authorization.
While the committee was persuaded by the evidence that a third dose of the Pfizer-BioNTech vaccine would help those at highest risk, the group was not convinced to include younger people now.
The group initially voted 16-2 to reject the idea of a third dose for everyone 16 years and older. That was a defeat for Pfizer, which wanted to make the booster shots available to all adults.
"We continue to believe in the benefits of a booster dose for a broader population," Kathrin Jansen, head of vaccine research and development at Pfizer, said in a statement after the meeting. "Boosters will be a critical tool in the ongoing effort to control the spread of this virus."
A recommendation for limited booster shots
Committee members proposed the more limited recommendation that FDA issue an emergency use authorization for a third dose of Pfizer for those over 65, and for people at high risk of severe cases of COVID-19. The vote for that proposal was unanimous (18-0).
Experts have said there is a clearer rationale and more data to support booster doses for those populations, at six months after their first two Pfizer shots. Several experts previously told Insider that boosters should be rolled out now for older adults.
The panel also voted to suggest that the FDA make the booster available to people who are at higher risk of being exposed to the virus at work, such as healthcare workers and teachers.
The FDA isn't required to follow the recommendations of its advisory committees, meaning it could still decide to approve booster shots for everyone 16 and older.
"The incremental benefit to the younger population really has not been demonstrated at all," Dr. Michael Kurilla, an infectious disease expert from the National Institutes of Health who sits on the panel, said during the meeting.
"I think we need to target the boosters right now specifically to the people who are likely to be at high risk, and it's an older population."
The FDA's interim leader, Dr. Janet Woodcock, signed on to an August 18 joint statement from a range of government health leaders that stated booster shots would be needed for the general public and would start rolling out on September 20, pending FDA and CDC reviews.
The Pfizer votes could also shape other booster-shot applications. Moderna has applied for FDA approval for a third dose, and Johnson & Johnson has also described preliminary data on giving an extra dose of its single-shot vaccine.
Experts have criticized Biden's booster-shot plan for being prematurely announced and potentially applying political pressure to the FDA and CDC review processes.
Several experts on the panel expressed concern that there wasn't enough safety data for the booster shot to recommend approving it for younger adults. In particular, they highlighted the risk of myocarditis, or heart inflammation, that has been seen at higher-than-usual levels in teenagers and 20-somethings who have been vaccinated.
"I have major concerns with regard to the extrapolation of data from much older populations to 16 and 17 year olds," said Dr. Archana Chatterjee, a pediatric infectious disease expert and dean of Chicago Medical School who sits on the panel. "We have no data on the safety in this population at all."
Data presented to FDA panel leans on Israel's experience
Some of the strongest data in favor of boosters comes from Israel, which began rolling out a booster to its older population at the end of July and has since offered it to people as young as 12.
Chatterjee called the data from Israel "compelling" for people over age 60.
Israeli health officials presented data to the panel showing a dramatic decrease in infections and severe disease among older people who received boosters. Their study compared these individuals to people who had received two doses and no booster.
Israel would have likely exceeded its hospital capacity if the nation waited longer to give boosters, Dr. Sharon Alroy-Preis, head of public health services for Israel's health department, told the committee.
Pfizer presented data showing protection from its vaccine against infection waned over time, particularly at six to eight months out. But a study from Kaiser Permanente showed protection against hospitalization was durable, remaining just as high five months out from vaccination.
The Israel data suggests that the booster can restore the initial highs of vaccine protection against infection. But there's no long-term data to know if that infection protection will last longer this time around. And the FDA's review made it clear the agency believes the vaccines are still working quite well at preventing hospitalization and death.
Still, getting unvaccinated people their first shots remains the top priority in the US.
"At this moment, it is clear that the unvaccinated are driving transmission in the United States," Amanda Cohn from the CDC said during the meeting.
Cohn said that masks and social distancing "will have to be part of the solution" too, because "vaccination will never be perfect" at preventing every case.