COVID-19 Vaccine Effectiveness and Recommendations
Vaccine Formulations and Targets
- The FDA approved updated 2024-2025 COVID-19 vaccines that target the Omicron JN.1 lineage strains, which are currently circulating in the United States, with Moderna and Pfizer-BioNTech vaccines based on the KP.2 strain and Novavax vaccine based on the JN.1 strain 1
- The updated formulations replaced the 2023-2024 vaccines that targeted XBB-sublineage strains, which are no longer predominant 2
Vaccine Effectiveness
- The Advisory Committee on Immunization Practices (ACIP) reviewed data showing 58% effectiveness of updated vaccines against XBB-sublineage infection at 60-119 days post-vaccination 2
- The ACIP also found 37% effectiveness against JN.1-sublineage infection at 60-119 days post-vaccination 2
- Vaccine effectiveness against hospitalization is 49% at 7-59 days after vaccination, declining to 14% at 120-179 days after vaccination 2
- Protection against critical illness appears more durable, with 69% effectiveness at 7-59 days and 32% at 120-179 days 2
- Pooled effectiveness against COVID-19-associated death was 23% 3, 2
Clinical Recommendations
- The ACIP recommends 2024-2025 COVID-19 vaccination for all persons aged ≥6 months to target currently circulating SARS-CoV-2 strains and provide additional protection against severe COVID-19-associated illness and death 1, 2
- The vaccines are FDA-approved for persons aged ≥12 years and authorized under Emergency Use Authorization for children aged 6 months-11 years 1
- While effectiveness against mild infection is moderate and wanes over time, protection against severe outcomes remains the primary benefit 3, 2
- Vaccine effectiveness is highest in the first 2 months after vaccination, with declining protection over time, particularly against hospitalization 2
Evidence Certainty and Important Considerations
- The certainty of evidence is rated as low for most outcomes in adults and adolescents, and very low for infants and children, meaning the true effectiveness may differ from these estimates 3, 2
- The vaccines provide better protection against severe outcomes than against infection itself, which is the most clinically relevant benefit for reducing morbidity and mortality 3, 2