The FDA has expanded its Emergency Use Authorizations (EUAs) for the COVID-19 vaccines manufactured by Pfizer/BioNTech (Comirnaty) and Moderna (Spikevax) to permit use of the bivalent formulations of these products (containing mRNA from the original and BA.4/5 Omicron strains of SARS-CoV-2) as a booster dose in children as young as 5 years old (Pfizer) or 6 years old (Moderna). The bivalent Pfizer vaccine had previously been authorized for use in persons ≥12 years old and the bivalent Moderna vaccine in persons ≥18 years old. Bivalent vaccines are not authorized for primary immunization against COVID-19. The monovalent Pfizer and Moderna COVID-19 vaccines are no longer authorized for use as booster doses in any age group.