FDA’s Expert Panel Recommends COVID-19 Booster Dose for Seniors and Others, Rejects Booster Dose for Children

Despite not convening the Vaccines and Related Biologic Products Advisory Committee (VRBPAC) last month to vote on effectiveness and safety of the Pfizer-BioNTech COVID-19 vaccine (licensed under the name COMIRNATY), the U.S. Food and Drug Administration (FDA) convened the advisory committee on Friday, Sept. 17, 2021 to vote on booster doses of the vaccine.¹

The FDA asked the VRBPAC to vote “yes” or “no” on the following question: Do the safety and effectiveness data from clinical trial C4591001 support approval of a COMIRNATY booster dose administered at least six months after completion of the primary series for use in individual 16 years of age and older?²

The C4591001 booster dose study did not include any subjects under 18 years of age and only 12 subjects 65-85 years of age in Phase 1 of the trial and none in Phase 2/3.³ Not surprisingly, the daylong meeting was punctuated by many VRBPAC members expressing doubt that the data Pfizer provided for younger age groups, especially teens and young men at increased risk of developing vaccine-associated myocarditis, was adequate to justify approving a booster dose.

Many FDA Committee Members Expressed Reservations About Pfizer Vaccine Booster Dose

Comments prior to the scheduled vote suggested that it was unlikely that many VRBPAC members would be unable to overcome their reservations about recommending a third dose of vaccine for children. Prior to the vote, committee members asked FDA officials if a different vote could be taken.

In response to that question, FDA’s outgoing Director of the Office of Vaccine Research and Review (OVRR), Dr. Marion Gruber, clarified that the vote before the VRBPAC was based on Pfizer’s request for approval of a third (booster) dose.⁴ The VRBPAC was instructed to vote on the question before them—authorization of a third dose of COMIRNATY for persons 16 years of age and up—and the vote to approve failed, with 16 “no” votes and two “yes” votes.

After taking a 10-minute break to cobble together a different vote per request of some VRBPAC members, a second vote and subsequent polling question was taken. Comments prior to the failed vote indicated that VRBPAC members would be comfortable recommending a third (booster) dose for persons 65 years of age and older and for those at higher risk of severe COVID-19 at least six months after completion of the two dose series.

Unscheduled Second Vote Taken by Committee to Approve Pfizer Booster for “High Risk” Individuals

For the second (unscheduled) vote, the FDA asked the VRBPAC to vote “yes” or “no” on the following question: Based on the totality of scientific evidence available, including the safety and effectiveness data from clinical trial C4591001, do the known and potential benefits outweigh the known and potential risks of a Pfizer-BioNTech COVID-19 vaccine booster dose administered at least six months after completion of the primary series for:

• individuals 65 years of age and older; and
• individuals at high risk of severe COVID-19.

This vote passed unanimously with 18 “yes” votes and 0 “no” votes. One VRBPAC member, pediatrician Jay Portnoy, MD (the temporary voting consumer representative), was so excited by the vote that he said, “I plan to go out and get my third vaccine this afternoon.”⁵

It’s important to note the data VRBPAC was asked to consider for Vote #2 is different than for Vote #1. For Vote #2 they were instructed to consider the “totality of scientific evidence available”—not just Pfizer’s booster dose clinical trial. Had the VRBPAC been required to only consider the evidence provided by Pfizer, it would have had to base its decision on data from only 12 subjects 65 years and older in Phase 1 of the trial because they were not included in Phase 2/3. The particular evidence basis for VRBPAC’s approval of a booster dose for this group was not specified.

Health Care Workers, Teachers, Other Employees Likely Considered “High Risk”

After Vote #2, VRBPAC members expressed concern about how “individuals at high risk of severe COVID-19” would be defined and who should be included in the EUA. The FDA’s Director for the Center for Biologics Evaluation and Research (CBER), Dr. Peter Marks, stated the FDA would interpret this language to mean healthcare workers. CDC’s Dr. Amanda Cohn further refined the language to mean people at higher risk due to occupational exposure⁶ and Dr. Marks explained that, in addition to healthcare workers, the group would include front line workers (like teachers) and potentially essential infrastructure workers⁷ and he requested that the VRBPAC immediately respond to a polling question to confirm that they were in agreement with that interpretation.

The FDA then asked the VRBPAC to vote “yes” or “no” on the following question: Should healthcare workers or others at high risk for occupational exposure be included in the EUA? VRBPAC voted unanimously in favor of that interpretation.⁸

Scope of Who Is Considered “High Risk” and Eligible for Booster Dose Greatly Expanded on Third Vote

It is important to note that the group to whom the recommendation would apply changed between Vote #2 “individuals at high risk of severe COVID-19” to the polling question “healthcare workers or others at high risk of occupational exposure.” This effectively shifted the focus from those who were at high risk of become severely ill from COVID-19 to those who are simply at high risk of being exposed, which will greatly expand the scope of those recommended to have a booster dose.

How will “others at high risk for occupational exposure” be defined? It’s not clear at this  point whether the FDA will adopt VRBPAC’s recommendations and if so, what the CDC’s Advisory Committee on Immunization Practices (ACIP) will do to define these groups.

Pfizer’s COMIRNATY Retains EUA Status and Full Liability Protection

Although it has been formally licensed by the FDA, COMIRNATY is in production and not yet available for use and is deemed by the FDA as interchangeable with the experimental Pfizer-BioNTech COVID-19 vaccine.⁹ The FDA has acknowledged receipt of NVIC’s request for clarification on what makes COMIRNATY “legally distinct” from the experimental vaccine currently in use, but has yet to provide NVIC with clarification.¹⁰ However, both vaccines have EUA status and as such are shielded from liability for their authorized uses, with vaccine injury claims to be governed by the less generous and more adversarial Countermeasures Injury Compensation Program (CICP).¹¹

During the meeting, Dr. Cohn also alleged that at this time it is apparent that the unvaccinated are driving transmission of the SARS-CoV-2 virus in the United States, and that a third dose will contribute to reduced transmission at some point in time.¹² Many VRBPAC members maintained that vaccinating the unvaccinated would be necessary to get a handle on the pandemic.

The next ACIP meeting is on Sept. 22 and 23. Generally, the ACIP meets to make specific vaccine use recommendations after FDA licenses or approves a vaccine for particular indications. To date, an agenda for this meeting has not been posted.¹³

Note: Vicky Pebsworth, PhD, RN, who is NVIC’s volunteer Director of Research and Patient Safety, was the consumer member of VRBPAC between 2007 and 2012.

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