On Mar. 1, 2023, BioNTech and Pfizer announced that they had submitted an application to the U.S. Food and Drug Administration (FDA) for Emergency Use Authorization (EUA) of a booster (fourth) dose of the companiesﾒ Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine in children 6 months through 4 years of age (also referred to as under 5 years).