2026 Flu Vaccine Less Effective Than 2025, CDC Analysis Shows

Vaccine reduced hospitalizations by 31% for adults and 41% for children, lower than previous season's performance.

Apr. 6, 2026 at 3:22pm

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An extreme close-up X-ray photograph revealing the intricate, ghostly structures of the human respiratory system, conceptually illustrating the clinical effects of the flu virus.An X-ray view of the human respiratory system highlights the clinical impact of the flu virus on the body.Cleveland Today

The flu vaccine for the 2025-2026 season was less effective than the previous year's, according to an analysis by the U.S. Centers for Disease Control and Prevention. The vaccine was between 22% and 34% effective in reducing flu-related outpatient visits for adults, and 30% to 41% for those 65 and older. It was about 31% effective in reducing flu-related hospitalizations for adults, and 41% for children 6 months to 17 years, lower than the previous season's performance.

Why it matters

The findings highlight the challenges in developing an effective flu vaccine each year, as the virus constantly mutates. The reduced effectiveness could lead to more severe flu seasons and higher rates of hospitalizations and deaths, especially among vulnerable populations.

The details

The CDC's analysis looked at vaccine effectiveness, a measure of how well a vaccine performs to reduce illness, hospitalizations, and deaths. During the previous 2024-2025 influenza season, the vaccine was 41% effective against hospitalizations for those ages 50 to 64, and 61% in children ages 6 months to 4 years. However, this season's flu vaccine was less effective, with a 31% reduction in flu-related hospitalizations for adults and 41% for children.

  • The analysis looked at vaccine effectiveness through February 2026.
  • Cuyahoga County has recorded 23 adult flu deaths between fall and the end of March.
  • The state reported one flu-associated pediatric death in December.
  • Nationally, there have been a total of 127 pediatric flu-related deaths during the 2025-2026 season, fewer than the 159 recorded the previous season.

The players

Patrick Maloney

An official from the CDC's National Center for Immunization and Respiratory Diseases.

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What they’re saying

“Influenza vaccination reduced the likelihood of both influenza-associated outpatient visits and hospitalizations.”

— Patrick Maloney, Official, CDC's National Center for Immunization and Respiratory Diseases

What’s next

The CDC continues to recommend routine annual flu vaccination for everyone ages 6 months and older, as flu season typically ends in May.

The takeaway

The reduced effectiveness of this season's flu vaccine highlights the ongoing challenges in developing an effective flu shot each year, as the virus constantly mutates. This could lead to more severe flu seasons and higher rates of hospitalizations and deaths, especially among vulnerable populations.