FDA Authorizes Second COVID-19 Vaccine Booster

The FDA authorized a second booster dose of either the Pfizer-BioNTech or the Moderna COVID-19 vaccines for people 50 and older and certain immunocompromised individuals.

Peter Marks, M.D., Ph.D.

“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, M.D., Ph.D., director of the FDA’s Center for Biologics Evaluation and Research, said in a news release.

In addition, the data show that an initial booster dose is “critical in helping to protect all adults from the potentially severe outcomes of COVID-19,” Marks said. “So, those who have not received their initial booster dose are strongly encouraged to do so.”

FDA’s decision applies only to the Pfizer-BioNTech and Moderna COVID-19 vaccines, and the authorization of a single booster dose for other age groups with these vaccines remains unchanged. “The agency will continue to evaluate data and information as it becomes available when considering the potential use of a second booster dose in other age groups,” the FDA said.

The agency amended its emergency use authorizations (EUA) for the two vaccines to say:

• A second booster dose of the Pfizer-BioNTech COVID-19 vaccine or Moderna COVID-19 vaccine may be administered to people 50 years of age and older at least four months after receipt of a first booster dose of any authorized or approved COVID-19 vaccine.

• A second booster dose of the Pfizer-BioNTech COVID-19 vaccine may be administered to people 12 years of age and older with certain kinds of immunocompromise at least four months after receipt of a first booster dose of any authorized or approved COVID-19 vaccine. “Immunocompromise” applies to those who have undergone solid organ transplantation or who are living with conditions that are considered to have an equivalent level of immunocompromise.

• A second booster dose of the Moderna COVID-19 vaccine may be administered at least four months after the first booster dose of any authorized or approved COVID-19 vaccine to people 18 years of age and older with the same certain kinds of immunocompromise.

The FDA determined that the benefits of the second booster dose outweighed the risks after reviewing data from Pfizer and BioNTech, Moderna, and sources outside of those companies.

The Ministry of Health of Israel provided safety data on the administration of about 700,000 fourth (second booster) doses of the Pfizer-BioNTech COVID-19 Vaccine given at least four months after the third dose in adults 18 years of age and older (about 600,000 of whom were 60 years of age or older).

The safety of Moderna COVID-19 vaccine, when administered as a second booster dose, is informed by experience with the Pfizer-BioNTech COVID-19 vaccine and safety information reported from an independently conducted study in which the Moderna COVID-19 vaccine was administered as a second booster dose to 120 participants 18 years of age and older who had received a two-dose primary series and a first booster dose of Pfizer-BioNTech COVID-19 vaccine at least 4 months prior.

“No new safety concerns were reported during up to three weeks of follow up after the second booster dose,” the FDA said.

In addition, immunogenicity data from an ongoing, open-label, non-randomized clinical study in healthcare workers at a single center in Israel were reported in a publication provided to the FDA.

In this study, individuals 18 years of age and older who had received primary vaccination and a first booster dose with Pfizer-BioNTech COVID-19 vaccine were administered a second booster dose of Pfizer-BioNTech COVID-19 vaccine (154 people) or Moderna COVID-19 vaccine (120 people) at least four months after the first booster dose.

Among these individuals, increases in neutralizing antibody levels against SARS-CoV-2 virus, including delta and omicron variants, were reported 2 weeks after the second booster as compared to 5 months after the first booster dose.