Pfizer has announced that the company has submitted an application to the U.S. Food and Drug Administration (FDA) for Emergency Use Authorization of an additional booster dose for adults 65 and older who have received an initial booster of any of the authorized or approved COVID-19 vaccines. The move was prompted by the result of two real-world data sets from Israel analyzed while Omicron variant was widely circulating. The data showed evidence that an additional mRNA booster increases immunogenicity and lowers rates of confirmed infections and severe illness.
What is did not prove was that a fourth dose prevents infection.
Moderna, however, is seeking FDA authorization for a 4th dose for all adults though infectious disease experts remain divided over whether or not a fourth shot is necessary.
As it stands, only those who are immunocompromised are eligible to receive fourth doses of messenger RNA vaccines.
The F.D.A. is expected to convene a meeting of its expert advisory committee next month to discuss fourth shots. In the meantime, the National Institutes of Health and vaccine manufacturers have been studying how the vaccines could be updated with results expected sometime this summer.
Meanwhile, the data from two CDC reports found that COVID-19 vaccine boosters remained safe and continued to be highly effective against severe disease over time.
The CDC continues to recommend everyone 5 and older remain up to date with recommended COVID-19 vaccinations, to ensure optimal protection against hospitalizations and severe outcomes.