The booster shot can be given to people at least six months after completion of the two-dose primary series in the following groups:
- individuals 65 years of age and older;
- individuals 18 through 64 years of age at high risk of severe COVID-19; and
- individuals 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 decision follows a vote from the FDA’s Vaccines and Related Biological Products Advisory Committee last week: where 16 out of 18 advisors opposed the broader proposal of booster authorization for anyone over 16. The panel did, however, unanimously recommend a booster dose for people older than 65 or with a high risk of severe COVID-19.
A third dose had already been previously authorized for individuals aged 12+ who have undergone solid organ transplant or are diagnosed with conditions that are considered to have an equivalent level of immunocompromise (with a booster shot administered after 28 days). This distinction with this week’s authorization is that a third dose for immunocompromised individuals addresses the fact two doses may not provide enough protection; as opposed to the need for a booster shot to address those who did have adequate protection initially but have since seen immunity wane.
The booster shot has been authorized under Pfizer/BioNTech’s EUA: but the vaccine is the same formulation as the now approved FDA-approved ‘Comirnaty’.
The next step will be for the Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) to meet to discuss a potential recommendation for the use and rollout of boosters to Americans.
Pfizer and BioNTech continue to supply the vaccine, including sufficient volume for boosters, under their existing supply agreement with the US government, which continues through April 2022. The companies say the introduction of booster doses in the US will not impact existing supply agreements around the world.
Booster shot data
In authorizing the booster shot yesterday, the FDA analyzed safety and immune response data from a subset of participants from the original clinical trial of the Pfizer-BioNTech COVID-19 Vaccine; as well as real world data from the US, UK and Israel.
The immune responses of approximately 200 participants 18 through 55 years of age who received a single booster dose approximately six months after their second dose were assessed. The antibody response against SARS-CoV-2 virus one month after a booster dose of the vaccine compared to the response one month after the two-dose primary series in the same individuals demonstrated a booster response.
Additional analysis conducted by Pfizer, as requested by the FDA, compared the rates of COVID-19 accrued during the current Delta variant surge among original clinical trial participants who completed the primary two-dose vaccination series early in the clinical trial to those who completed a two-dose series later in the study. The analysis submitted by the company showed that during the study period of July and August 2021, the incidence of COVID-19 was higher among the participants who completed their primary vaccine series earlier, compared to participants who completed it later. The FDA determined that the rate of breakthrough COVID-19 reported during this time period translates to a ‘modest decrease’ in the efficacy of the vaccine among those vaccinated earlier.
“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,” said Acting FDA Commissioner Janet Woodcock, M.D.
“This pandemic is dynamic and evolving, with new data about vaccine safety and effectiveness becoming available every day. 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.”