Influenza Activity and Estimated Vaccine Effectiveness During the 2025-2026 Influenza Season - PubMed
5 hours ago
- #Vaccine Effectiveness
- #Influenza Surveillance
- #Antigenic Drift
- Antigenically drifted influenza A(H3N2) J.2.4.1 (subclade K) viruses were predominant during the 2025-2026 Northern Hemisphere season.
- Interim vaccine effectiveness was estimated at 35% against influenza-associated emergency/urgent care and 27% against hospitalizations.
- The estimated cumulative influenza-associated hospitalization rate was 80 per 100,000, correlating with millions of illnesses and thousands of deaths in the US.
- Post-vaccination neutralizing antibody titers against subclade K were reduced 1.62-fold compared to the vaccine virus, but all tested viruses remained sensitive to antivirals.