CDC Reports Reduced Effectiveness of 2025-2026 Influenza Vaccine
Filmogaz.com — Interim estimates published in the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report show lower influenza vaccine effectiveness this season. The report was released in the March 12 issue.
Study design
Patrick Maloney, Ph.D., and colleagues at the CDC in Atlanta led the analysis. They used data from three U.S. respiratory virus vaccine effectiveness networks.
The team evaluated patients with acute respiratory illness seen in outpatient clinics and hospitals. The analysis focused on the 2025 to 2026 influenza season.
Overall results
The CDC reports reduced effectiveness of the 2025-2026 influenza vaccine compared with recent seasons. Despite reduced VE, the vaccine still showed measurable protection for children, adolescents, and adults.
- Children and adolescents (<18 years): VE was 38% to 41% against outpatient visits.
- Children and adolescents: VE was 41% against influenza-associated hospitalization.
- Adults (≥18 years): VE ranged from 22% to 34% against outpatient visits.
- Adults: VE was 30% against influenza-associated hospitalization.
By influenza type
Vaccine effectiveness varied by viral type and age group. Influenza A VE differed modestly between settings.
- Influenza A — children and adolescents: about 37% against outpatient visits, 42% against hospitalization.
- Influenza A — adults: about 34% against outpatient visits, 30% against hospitalization.
- Influenza A(H3N2) — children and adolescents: 35% against outpatient visits and 38% against hospitalization.
- Influenza B — adults: 63% effectiveness against outpatient visits.
- Influenza B — children and adolescents: VE ranged from 45% to 71% for outpatient visits.
Author conclusions and context
The investigators noted that even when overall effectiveness is lower, vaccination continues to reduce severe illness. They reported that vaccination has prevented thousands of hospitalizations and deaths in past seasons.
These figures are interim estimates drawn from the three VE networks. The full MMWR report in the March 12 issue provides detailed methods and data.
