The US Food and Drug Administration (FDA) has authorized updated COVID-19 booster shots targeting the Omicron variants BA.4 and BA.5 from Pfizer/BioNTech and Moderna.
The updated Pfizer/BioNTech vaccine is now approved for use as a single booster dose in individuals 12 years of age and older, while new Moderna’s vaccine is for all adults over the age of 18.
People are eligible for an updated booster dose at least two months following primary or booster vaccination.
Both vaccines are bivalent, which means they target the original strain of the SARS-CoV-2 virus and the Omicron variants BA.4 and BA.5 that account for more than 90% of new COVID-19 cases in the US.
“The COVID-19 vaccines, including boosters, continue to save countless lives and prevent the most serious outcomes (hospitalization and death) of COVID-19,” said FDA Commissioner Robert M. Califf, MD, in a statement.
“As we head into fall and begin to spend more time indoors, we strongly encourage anyone who is eligible to consider receiving a booster dose with a bivalent COVID-19 vaccine to provide better protection against currently circulating variants."
The monovalent Moderna and Pfizer/BioNTech COVID-19 vaccines — the ones targeting the original strain of the virus — will no longer be administered as boosters for individuals 18 years and older and 12 years and older, respectively.
Nevertheless, the monovalent Pfizer/BioNTech remains authorized as a single booster dose for individuals 5 through 11 years of age at least five months after completing a primary series of the vaccine, the FDA says.
Pfizer said in a press release that the company is now working with the FDA to prepare an application for an Omicron-adapted bivalent vaccine in children 6 months through 4 years of age.
Concerns over strategy
Pfizer/BioNTech and Moderna completed their submissions to the FDA requesting the EUA for their bivalent booster doses last week. The agency based its decision on data from the clinical studies of a bivalent vaccine targeting the Omicron variant BA.1 and the preclinical trials in mice from Omicron BA.4/BA.5-adapted vaccine.
This streamlined approach has raised some concerns among vaccine experts, who say that the lack of data from clinical trials could discourage people from getting a booster shot. However, experts note that the health risks of using such vaccines remain very low, and the FDA follows the same procedure to authorize updated flu shots every year.
The agency defended its strategy by saying that the real-world data from the currently used mRNA COVID-19 vaccines that have been administered to millions of people shows that the booster shots are safe and effective.
The updated vaccines can be administered after the Centers for Disease Control and Prevention (CDC) issues a recommendation on using them. The CDC vaccine advisory group will vote on Thursday.