Pfizer and BioNTech have received FDA Emergency Use Authorization (EUA) for a third booster dose for their COVID-19 vaccine that is broader than recommended last week by an advisory panel to the agency.

The EUA, granted late Wednesday, allows booster doses in adults ages 65 and older, as recommended unanimously by the FDA’s Vaccines and Related Biological Products Advisory Committee.

But while the advisory committee voted 16–2 against recommending the booster doses be given to people ages 16 and older after a contentious hearing, the FDA went beyond the panel’s advice by extending its emergency authorization to adults ages 18–64 who are at high risk of severe COVID-19; as well as to adults ages 18–64 whose “frequent institutional or occupational exposure” to SARS-CoV-2 puts them at high risk of serious complications of COVID-19 including severe COVID-19.

The FDA usually follows the recommendations of advisory committees like the one that considered the vaccine on September 17 in a sometimes contentious day-long virtual meeting.

Booster doses are authorized at least six months following completion of the initial two doses of the Pfizer/BioNTech vaccine, and may be given at any point after that time, according to the FDA.

“After considering the totality of the available scientific evidence and the deliberations of our advisory committee of independent, external experts, the FDA amended the EUA for the Pfizer-BioNTech COVID-19 vaccine to allow for a booster dose in certain populations such as health care workers, teachers and day care staff, grocery workers, and those in homeless shelters or prisons, among others,” acting FDA Commissioner Janet Woodcock, MD, said in a statement.

Those authorizations may be expanded over time, Woodcock hinted: “As we learn more about the safety and effectiveness of COVID-19 vaccines, including the use of a booster dose, we will continue to evaluate the rapidly changing science and keep the public informed.”

Booster response cited

The FDA said it based its decision on several trials conducted in the United States, the U.K., and Israel. In one study of approximately 200 participants 18 through 55 years of age, a booster response was seen among people administered a single booster dose about six months after their second dose.

Also, the agency cited a study by Pfizer showing that among cases of COVID-19 reported after July 1 by participants in the companies’ global Phase III trial (NCT04368728), those who were vaccinated later in the trial—and originally received a placebo—experienced 26% higher efficacy than those who were vaccinated earlier as part of the original group.

“We expect Pfizer to return to the FDA with more data in the next few months to reassure the agency, and to then broaden the EUA to a sBLA [supplemental Biologics License Application] for ‘boosters for all’ by year-end,” Geoffrey C. Porges, MBBS, director of therapeutics research and a senior research analyst at SVB Leerink, wrote Monday in a research note following the advisory committee meeting.

Based on the expectation of at least some booster doses being authorized in the United States and Europe, Porges raised SVB Leerink’s 2021 sales estimate for the vaccine to $39.5 billion, up 13% from $35 billion.

The original EUA, granted in December 2020, authorized the use of the vaccine in individuals 16 years of age and older. That EUA was expanded in May to include those 12 through 15 years of age.

On August 23, the FDA granted full approval to the two-dose vaccine—which is being marketed under the name COMIRNATY® (BNT162b2)—in individuals ages 16 and older. The vaccine is also available under EUA for adolescents ages 12–15 years of age. Earlier last month, the agency expanded the EUA to allow administration of a third booster dose in solid organ transplant recipients or those who are diagnosed with conditions that are considered to have an equivalent level of immunocompromise.

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