While the Johnson & Johnson (Janssen) vaccine is a single-dose vaccine, CDC recommends that people stay up to date with their vaccinations and get boosted when eligible. People who received the Johnson & Johnson vaccine are eligible to receive an updated mRNA booster dose if at least 2 months have passed since their first Johnson & Johnson dose 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 cause most cases. Updated boosters are expected to provide better protection against the virus and address waning vaccine effectiveness over time.
The Johnson & Johnson booster vaccine is authorized for anyone age 18 and older as a single booster dose after the primary vaccine if no other approved vaccine is available.See additional recommendations for people who are moderately to severely immunocompromised.