The Food and Drug Administration released a review of Pfizer’s application for a COVID-19 booster shot on Wednesday, saying that although the third shots increased immune responses in study participants, the company’s vaccine was holding up strongly against severe forms of the virus without an additional shot.
The agency released the company’s application just days before the FDA will convene an outside committee of experts to recommend whether to approve the booster proposal. President Joe Biden announced last month that the government would begin offering third shots next week to people eight months after they got their second jab of the Pfizer-BioNTech inoculations, contingent on FDA approval and a recommendation from the Centers for Disease Control and Prevention.
But that timeline has come under scrutiny this week amid a series of studies into the need for booster shots amid the spread of the highly transmissible delta variant of the virus. All three of the vaccines being used in the U.S. provide strong protection against COVID-19, including the delta variant, although studies show that some vaccines’ effectiveness does decline about six months after a second jab.
Pfizer noted in its application that its vaccine’s effectiveness against symptomatic cases of COVID-19 fell from about 96% to 84% after six months but was still extremely effective at preventing severe cases of the disease. The company says a third dose would restore the vaccine’s effectiveness to about 95%.
“Overall, data indicate that currently U.S.-licensed or authorized COVID-19 vaccines still afford protection against severe COVID-19 disease and death in the United States,” the FDA wrote in its review of the Pfizer application.
The FDA is not required to follow the advice of its outside panel of experts, which will be convened Friday, but it often does. The agency did say that Pfizer’s booster application met specified conditions the pharmaceutical company needed to adhere to with its booster shots.
The New York Times notes the FDA’s caveats could affect how the White House’s booster program is rolled out. The agency could scale back any authorization for a third Pfizer-BioNTech jab or recommend boosters only to certain subsets of the population, such as those 65 and older or with underlying conditions, the newspaper added.
Either strategy would undercut Biden’s plans for a broad rollout of the booster shots.
Two top regulators at the FDA on Monday also published a review that questioned the need for an immediate booster shot program for the general public. The two scientists, Dr. Philip Krause and Dr. Marion Gruber, lead the FDA’s vaccine office and said that, although they were not writing on behalf of the agency, they believed no study had “provided credible evidence of substantial declining protection against severe disease” in those who have been fully vaccinated against COVID-19.
In light of the doctors’ comments, the FDA said this week that it was still in the “middle of a deliberative process of reviewing Pfizer’s booster shot supplemental approval submission, and F.D.A. as a matter of practice does not comment on pending matters before the agency.”
“We look forward to a robust and transparent discussion on Friday about that application,” the agency said.
This article originally appeared on HuffPost and has been updated.