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Influenza Vaccine Composition for the 2025-2026 U.S. Influenza Season

Today, the FDA made recommendations to vaccine manufacturers for the virus strains to be used in influenza (flu) vaccines for the 2025-2026 U.S. flu season following a thorough and comprehensive review of U.S. and global surveillance data. With today’s action, the FDA does not anticipate any impact on timing or availability of vaccines for the American public. The recommendations are similar to the previous year’s strain selection.

To inform the selection of the flu virus strains, the FDA convened a meeting of scientific and public health experts from the FDA, Centers for Disease Control and Prevention and Department of Defense for this in-depth discussion. During the meeting, these federal partners collaboratively evaluated and analyzed U.S. and global surveillance data related to the epidemiology and antigenic characteristics of flu viruses currently circulating.

Key topics discussed during today’s meeting that informed FDA’s recommendation to vaccine manufacturers included:

  • Data and information on flu virus strains that are circulating in the U.S. and globally and the types that are causing disease;
  • Data and information on mid-season vaccine effectiveness for the 2024-2025 vaccines; and
  • Information on candidate vaccine virus strains for use in manufacturing flu vaccines for the upcoming flu season

Additional Information:

Trivalent seasonal influenza vaccines include two influenza A subtype viruses (H1N1 and H3N2) and one influenza type B virus. Influenza virus strains were selected based on the influenza vaccine production method: egg-based and cell- or recombinant-based. 

As a result of the meeting with the federal partners, the FDA recommends that the trivalent formulation of egg-based influenza vaccines for the 2025-2026 U.S. influenza season contain the following:

  • an A/Victoria/4897/2022 (H1N1)pdm09-like virus;
  • an A/Croatia/10136RV/2023 (H3N2)-like virus; and
  • a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.

The FDA recommends that the trivalent formulation of cell- or recombinant-based influenza vaccines for the 2025-2026 U.S. influenza season contain the following:

  • an A/Wisconsin/67/2022 (H1N1)pdm09-like virus;
  • an A/District of Columbia/27/2023 (H3N2)-like virus; and
  • a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.

The FDA has informed the manufacturers of FDA-approved seasonal influenza vaccines of these recommendations. The FDA anticipates that there will be an adequate and diverse supply of approved trivalent seasonal influenza vaccines for the 2025-2026 U.S. influenza season.

March 13, 2025, Interagency Meeting Participants

FDA:Sudhakar Agnihothram, Ph.D.
Karin Bok, M.S., Ph.D.
Robert Daniels, Ph.D.
Maryna Eichelberger, Ph.D.
Manju Joshi, Ph.D.
David C. Kaslow, M.D.
Peter Marks, M.D., Ph.D.
Julie Tierney, J.D. 
Jerry Weir, Ph.D.
Zhiping Ye, M.D., Ph.D.
CDC:Vivien Dugan, Ph.D.
Lisa Grohskopf, M.D., M.P.H.
Rebecca Kondor, Ph.D.
DoD:Anthony Fries, Ph.D.
Shayne Gallaway, Ph.D., M.P.H.

Slides and the agenda from the March 13th, 2025, meeting of federal government participants can be found below:

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