The FDA granted expanded emergency authorizations for second booster doses of either the Pfizer/BioNTech or the Moderna COVID-19 vaccines for older adults and some immunocompromised populations, with the agency saying it aimed to better protect from the virus and its variants people who are at higher risk of severe disease, hospitalization, and death.
The FDA cited data submitted by the companies showing that second booster doses of their mRNA vaccines improved protection against severe COVID-19 and would not lead to new safety concerns.
Through amendments to existing emergency use authorizations (EUAs), the FDA allowed patients to receive a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccines for adults ages 50 years and older, to be administered at least four months after their first booster dose of any authorized or approved COVID-19 vaccine.
“Current evidence suggests some waning of protection over time against serious outcomes from COVID-19 in older and immunocompromised individuals. Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals,” Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement.
Marks added that the data also showed that an initial booster dose “is critical in helping to protect all adults from the potentially severe outcomes of COVID-19.”
The FDA has also allowed:
- A second booster dose of the Pfizer-BioNTech vaccine for people 12 years of age and older with some forms of immunocompromised, to be given at least four months after receipt of a first booster dose of any authorized or approved COVID-19 vaccine. The FDA defined those forms as including people who have undergone solid organ transplantation or live with conditions deemed to have an equivalent level of immunocompromise.
- A second booster dose of the Moderna COVID-19 vaccine to be administered at least four months after the first booster dose of any authorized or approved COVID-19 vaccine to adults ages 18 years and older with the same forms of immunocompromise.
Assessing further data
For all other age groups, only a single booster dose of either vaccine is authorized—though the FDA said it will continue to assess data on the effects of a second booster dose on other populations.
The first Pfizer/BioNTech booster dose was first authorized for emergency use on September 22, 2021, in individuals 65 years and older, and expanded to all adults 18 years of age and older by the FDA on November 19. The expanded EUA covered a broader population of patients than those for which the vaccine has been fully approved under the name COMIRNATY®.
That same day, the agency authorized the first booster dose for Moderna’s vaccine at the 50 µg dose level to all adults aged 18 and older who completed a primary vaccination with any other authorized or approved COVID-19 vaccine—including Moderna’s which has been fully approved under the name SpikeVax™.
The vaccine developers both filed for expanded EUAs just two weeks ago. The FDA signaled its intent to approve the second booster doses quickly when it opted not to convene a meeting of its Vaccines and Related Biological Products Advisory Committee, as was done when the vaccines first underwent review by the agency two years ago.
Pfizer/BioNTech applied on March 15 for an expanded EUA allowing an additional booster dose for adults 65 years of age and older who had received an initial booster of any of the authorized or approved COVID-19 vaccines.
Pfizer/BioNTech’s submission was based on two real-world data sets from Israel analyzed when the Omicron variant was widely circulating. In one dataset, rates of confirmed infections were two times lower, and rates of severe illness four times lower, among individuals who received an additional booster dose of the Pfizer-BioNTech COVID-19 Vaccine administered at least four months after the first booster dose (third dose overall).
That data, according to the companies, came from an analysis of Israeli Ministry of Health records of more than 1.1 million adults 60 years of age and older who had no known history of SARS-CoV-2 infection and were eligible for an additional (fourth dose overall) booster.
In a second Israeli study, neutralizing antibody titers increased approximately 7-fold to 8-fold at two and three weeks after the fourth dose compared to five months after the third dose, among 154 (out of 700) participants who received a fourth dose of the Pfizer-BioNTech COVID-19 vaccine at least four months following the third dose.
On March 17, Moderna requested that the FDA amend its EUA to allow a fourth dose of its COVID-19 vaccine in adults 18 years of age and older who have received an initial booster of any of the authorized or approved COVID-19 vaccines—a submission based in part on recently published data generated in the United States and Israel following the emergence of Omicron.
Moderna said its request to include adults over 18 years of age was made to provide flexibility for the U.S. Centers for Disease Control and Prevention (CDC) and healthcare providers to determine the appropriate use of an additional booster dose of the vaccine, including for those at higher risk of COVID-19 due to age or comorbidities.