The booster is to be administered at least six months after the completion of the primary series of vaccination. The authorization extends to individuals who are; 65 years of age and older, 18 through 64 years of age at high risk of severe COVID-19, and 18 through 64 years of age 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 held a public meeting on September 17, to collect input from independent scientific and public health experts on the data submitted in Pfizer's application.
"The FDA considered the data that the vaccine manufacturer submitted, information presented at the VRBPAC meeting, and the committee’s discussion, and has determined that based on the totality of the available scientific evidence, a booster dose of Pfizer-BioNTech COVID-19 Vaccine may be effective in preventing COVID-19 and that the known and potential benefits of a booster dose outweigh the known and potential risks."
The FDA concluded that over time, the vaccine experienced "a modest decrease in the efficacy." The boosters were shown to generate an antibody response against SARS-CoV-2 similar to the one experienced directly following an individual's initial two-dose vaccination.
The CDC has opened a meeting to create further guidelines over when and who will receive booster shots. While the FDA has approved the Pfizer booster, experts at the CDC meeting were confused by the rationale for booster shots and they suggested waiting a month for more evidence to make a decision.
The two agencies being at odds over this decision is not surprising. The FDA approves the efficacy and safety of drugs, while the CDC is tasked, in the case of the coronavirus pandemic, with figuring out the supply and distribution of the vaccine. Those that have been vaccinated still show tremendous resistance to Covid and it's not entirely known if booster shots are necessary to maintain that.
The CDC and FDA agree that seniors and health care workers are in most need of booster shots. Data provided by Pfizer and the Israeli government showed strong evidence for their efficacy in seniors, but less conclusive data for younger individuals without underlying health conditions.
Keeping healthcare workers safe from the virus remains a priority. In some areas of the country, the healthcare system is overwhelmed, and losing a worker to mild covid symptoms could leave healthcare providers understaffed.
The World Health Organization has voiced its opposition to the US's plan for booster shots. They argue that wealthy nations shouldn't splurge on a third round of vaccinations, while poorer nations wait for their first.
The FDA and CDC will decide at a later date if those that received the Moderna or Johnson & Johnson vaccinations are in need of boosters. At this time, they don't recommend individuals get a different brand of booster to their original vaccine.