FDA advisers to vote on Pfizer’s COVID-19 booster shots

A panel of the Food and Drug Administration’s vaccine advisers is meeting Friday to discuss third doses of Pfizer-BioNTech’s COVID-19 vaccine, a key first step towards the Biden administration’s plans to initiate the U.S.’ first booster shots later this month.

The members of the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) are scheduled to vote by 4:45 p.m. over whether there is enough data to support changing Pfizer’s full approval to include an additional shot of the vaccine, known by the brand name Comirnaty, six months after Americans received the second shot in the two-dose vaccination. The FDA has previously convened its advisers for other key vaccine decisions — last year it met on whether to grant emergency authorization to Pfizer’s vaccine. While not binding, a supportive vote from the panel could lend legitimacy to the FDA’s ultimate decision over whether to approve Pfizer’s booster dose application.

“If they say, ‘we don’t think there’s enough data to do a booster,’ then so be it,” Dr. Anthony Fauci, the president’s chief medical adviser, told Kaiser Health News. But he added, “I think that would be a mistake, to be honest with you.”

Advisers to a different panel for the Centers for Disease Control and Prevention will take the next step in the process, if the FDA grants its approval. Under federal supply agreements, even FDA-approved boosters cannot be given until the CDC’s Advisory Committee on Immunization Practices issues recommendations governing the shots.

That group is expected to meet to discuss booster shots as early as Wednesday.

At previous meetings, the ACIP has considered the possibility that booster shots should first be prioritized only for older Americans at the highest risk for severe breakthrough cases and for essential frontline workers like healthcare providers, who cannot work with even mild infections. It has also previously considered the possibility that the shots may be given later than six months; the Biden administration had initially aimed for boosters to be given eight months after shots were first completed.

“We have to separate the political and the scientific. Because there’s a political decision that can be made about whether you think it’s right to get everyone vaccinated across the globe before people get the third dose,” Dr. Peter Marks, the FDA’s top vaccine official, said Wednesday at a virtual meeting hosted by ResearchAmerica.

Two senior outgoing FDA officials publicly broke with the Biden administration’s announced plans to roll out booster shots earlier this week, co-authoring a review led by the World Health Organization that concluded that “current vaccine supplies could save more lives if used in previous unvaccinated populations” than as boosters.

Marks denied there was “political pressure” on the regulator to approve booster shots, suggesting Pfizer’s vaccine may have needed to be a three-dose regimen all along.

“On the other hand, there is a scientific issue of what is the right thing to do to maximally protect against further circulation of COVID-19,” Marks said.

The FDA and CDC are scheduled to present data to the VRBPAC at tomorrow’s meeting, in addition to health experts and officials from the United Kingdom and Israel — where authorities have already decided to roll out booster shots.

According to slides posted ahead of the Israeli health ministry’s presentation, authorities calculated that waning vaccine effectiveness there from Pfizer’s shots risked a surge in hospitalizations that “could have significantly exceeded the national capacity” if boosters had not been rolled out.

“I am fully confident that when people come to the advisory committee meeting and tune in on September 17, and they witness the Israelis presenting their data and they they witness other data being presented, that there will be a good rationale for why boosters might be necessary,” Dr. Peter Marks told a meeting of the Regulatory Affairs Professionals Society earlier this week.

Pfizer also shared new data from its own trials in its 53-page report to the VRBPAC published this week, arguing that its booster dose appeared safe and effective at reversing waning protection against the virus.

“The totality of the available data supports the public health need for a booster,” Pfizer’s scientists said in the document.

However, the meeting is unlikely to offer clear answers for recipients of other vaccines who are hoping for booster shots.

Moderna only recently completed its own submission for a smaller 50-microgram booster dose of its vaccine, a move that the company says could free up additional supply. But  the Biden administration has questioned whether the company submitted enough data to support halving its third dose from its initial 100 microgram shots — a move that could both present logistical challenges and be less effective.

Johnson & Johnson is also waiting for results from its own trials, which could decide whether the drugmaker seeks full approval for a two-dose series of its vaccine from the FDA.

And a widely anticipated “mix-and-match” booster study, backed by the National Institutes of Health, is not expected to release results for giving an additional Pfizer booster to recipients of Moderna or Johnson & Johnson’s vaccine until later this year.

“We already have data, which likely will be in a preprint form, of Moderna’s boost superimposed upon either a Pfizer, Moderna, or J&J,” Fauci told a meeting of the National Institute of Allergy and Infectious Diseases Council.

“We haven’t yet gotten to— We will probably, end of September, beginning of October, to the Pfizer boost superimposed upon a Moderna,” added Fauci.