How Effective Is The Flu Vaccine? May 2026

For the current , the vaccine is estimated to be 36% effective overall at preventing medically attended flu illness. While this is lower than the typical 40–60% range, it still significantly reduces the risk of severe complications, hospitalizations, and deaths. Key Effectiveness Data (2025–26 Season) Overall Effectiveness: 36% (interim estimate). By Age Group:

30%–42% effective depending on age and setting. Influenza B: 45%–71% effective. Why Effectiveness Varies How Effective is the Flu Vaccine?

38%–41% effective against outpatient visits and 41% against hospitalizations. For the current , the vaccine is estimated