On Mar. 15, 2022, Pfizer and BioNTech announced the companies had submitted an application to the U.S. Food and Drug Administration for Emergency Use Authorization (EUA) of an additional booster dose adults 65 years of age and older who have received an initial booster of any of the authorized or approved COVID-19 vaccines.

The submission was based on two real-world data sets from Israel analyzed at a time when the Omicron variant was widely circulating. Both data sets showed evidence that an additional mRNA booster increases immunogenicity and lowers rates of confirmed infections and severe illness.