The CDC recommends people 5 and older receive an age-appropriate, updated mRNA booster dose if at least 2 months have passed since their primary series or since their most recent booster dose. Updated boosters of Pfizer-BioNTech and Moderna contain a bivalent formula that both boosts immunity against the original coronavirus strain and also protects against the newer Omicron variants that now cause most cases. Updated boosters are expected to provide better protection against the virus and address waning vaccine effectiveness over time.

See additional recommendations for people who are moderately to severely immunocompromised.