N Engl J Med

Respiratory virus vaccines show sustained effectiveness and safety

November 5, 2025

Study details: A systematic review of U.S.-licensed vaccines for COVID-19, RSV, and influenza analyzed 511 studies from major databases, updating the 2023–2024 ACIP review. Outcomes included vaccine effectiveness (VE) against hospitalization and safety profiles.

Results:

• COVID-19: XBB.1.5 mRNA vaccines showed VE of 46% to 50% in adults and 37% in immunocompromised adults; KP.2-adapted vaccines reached 68%.
• RSV: Maternal RSVpreF, infant nirsevimab, and older-adult vaccines each achieved ≥68% VE against hospitalization.
• Influenza: VE was 48% in adults and 67% in children.
• Safety remained consistent: myocarditis associated with Covid-19 vaccines occurred at 1.3 to 3.1 per 100,000 adolescent doses; RSVpreF was associated with ~18 excess Guillain–Barré cases per million older-adult doses; no significant preterm birth risk was observed when RSVpreF was given at 32 to 36 weeks' gestation.

Clinical impact: Evidence supports continued seasonal immunization to reduce severe outcomes. Variant-specific COVID-19 updates and monitoring for rare adverse events remain critical for optimal protection.

Source:

Scott J, et al. (2025, October 29). N Engl J Med. Updated Evidence for Covid-19, RSV, and Influenza Vaccines for 2025-2026. https://pubmed.ncbi.nlm.nih.gov/41160817/