The panel was charged with deciding if the benefits of the vaccine outweighs the risks, paving the way for the possibility that immunizations could begin within days.
An FDA advisory panel Thursday endorsed Pfizer and BioNTech’s vaccine to prevent coronavirus disease 2019 (COVID-19), paving the way for the possibility that immunizations could begin within days.
The full FDA could now grant Pfizer and BioNTech an emergency use authorization (EUA) for the vaccine. Although the full FDA is not required to accept the recommendations of its outside advisory panels, it usually does.
Voting after a public, day-long meeting intended to shore up vaccine confidence with the American public, the Vaccines and Related Biological Products Advisory Committee (VRBPAC) was charged with deciding whether the benefits of the vaccine outweigh the risks, based on available data, for those 16 and older.
As the vote neared, several panel members expressed concerns about giving the vaccine to 16- and 17-year-olds; the vote was 17-4, with 1 abstention.
Some panel members also noted that the UK health regulatory agency Wednesday announced that individuals "with a history of anaphylaxis to a vaccine, medicine or food" should not receive the shot after 2 health care workers, both of whom carried epinephrine to treat severe allergic reactions, had anaphylaxis soon after administration.
COVID-19, which exacted its highest 1-day death toll on Americans so far on Wednesday with more than 3000 dead, is caused by a highly transmissible, airborne virus in asymptomatic individuals as well as those with clinical signs of illness. The pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has killed close to 300,000 Americans since the early part of this year.
The vaccine, BNT162b2, is based on the SARS-CoV-2 spike glycoprotein antigen encoded by RNA and formulated in lipid nanoparticles. It is given in 2 doses 21 days apart. In November, the companies announced that efficacy after the second dose is 95%.
The recommendation to approve the EUA comes as the phase 3 trial continues; the data was based on a randomized, double-blinded and placebo-controlled trial in about 44,000 participants, all adults 18 and over.
The most common adverse events were injection-site reactions (84.1%), fatigue (62.9%), headache (55.1%), muscle pain (38.3%), chills (31.9%), joint pain (23.6%), fever (14.2%).
Severe adverse reactions occurred in up to 4.6% of participants and were more frequent after the second dose than the first dose. Adverse reactions were also more common in individuals younger than 55 compared with older individuals.
Under an EUA, the benefits of the vaccine are considered to outweigh any risks and it is still considered unapproved while it is further analyzed under an Investigational New Drug Application until it is licensed under a Biologics License Application (BLA).
During the sponsor presentation, William C. Gruber, MD, senior vice president, Vaccine Clinical Research and Development at Pfizer, said the vaccine was affective across those with cormorbidities, including chronic obstructive pulmonary disease, cardiovascular disease, diabetes, obesity, and HIV.
Efficacy was also similar across ages, genders, and racial and ethnic groups, Gruber said. About 10% of the study population was Black, and participants, who were randomized 1:1 to receive either the vaccine or placebo, were split roughly between men and women.
In addition, the vaccine protected against severe disease, defined as hospitalization, admission to an intensive care unit, or intubation or mechanical ventilation leading to death. Whether the vaccines benefit children under 16 is still unknown, but the trial is recruiting children over age 12 for further study.
During the panel's deliberation, Paul Offit, MD, an infectious disease expert and professor of pediatrics at The Children's Hospital of Philadelphia, asked for more information about the reactions in the United Kingdom, which began vaccinations of health care workers and older adults Tuesday. There are "tens of millions of people in this country" with food allergies who are going to think they cannot get the vaccine, he said.
One of the workers who had a reaction had a severe allergy to eggs and other foods, according to Pfizer's executive in charge of safety, and the other worker had a drug allergy. The reactions happened within minutes of the dose. Both recovered with epinephrine.
One panel member, H. Cody Meissner, MD, an infectious disease specialist and professor of pediatrics at Tufts University School of Medicine, noted that any vaccine is capable of producing an allergic reaction, and Pfizer added that the fact sheets and prescribing information will note that the vaccine should not be given to anyone with a known history of severe reactions to any of the components of the vaccine.
Gruber said they did not see severe allergic reactions among US participants in the trial, and only people with known severe reactions to previous vaccines were excluded.
The panel also discussed what to advise pregnant women, but did not reach a conclusion.
Earlier in the day, Nancy Messonnier, MD, the director of the National Center for Immunization and Respiratory Diseases at the CDC, said health care workers and residents of nursing homes, who are slated to be among the first to receive available doses, will be tracked to follow outcomes. The tracking will be voluntary, but she said she hopes as many people as possible agree to it.
Next week, the same panel will vote on whether to recommend an EUA for a vaccine from Moderna.
The Pfizer vaccine has also been approved by Canada and Bahrain.