FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) met in Silver Spring, Maryland, on March 7, 2023, to select the influenza viruses for the composition of the influenza vaccine for the 2023-2024 U.S. influenza season. During this meeting, the advisory committee reviewed and evaluated the surveillance data related to epidemiology and antigenic characteristics of recent influenza isolates, serological responses to 2022-2023 vaccines, and the availability of candidate strains and reagents.

Influenza virus strains were selected based on the influenza vaccine production method; egg-based and cell- or recombinant-based.

The committee recommended that the quadrivalent formulation of egg-based influenza vaccines for the U.S. 2023-2024 influenza season contain the following:

• •    an A/Victoria/4897/2022 (H1N1)pdm09-like virus;
• •    an A/Darwin/9/2021 (H3N2)-like virus;
• •    a B/Austria/1359417/2021-like virus (B/Victoria lineage);
• •    a B/Phuket/3073/2013-like virus (B/Yamagata lineage). 

The committee recommended that the quadrivalent formulation of cell- or recombinant-based influenza vaccines for the U.S. 2023-2024 influenza season contain the following:

• •    an A/Wisconsin/67/2022 (H1N1)pdm09-like virus;
• •    an A/Darwin/6/2021 (H3N2)-like virus;
• •    a B/Austria/1359417/2021-like virus (B/Victoria lineage);
• •    a B/Phuket/3073/2013-like virus (B/Yamagata lineage).

For trivalent influenza vaccines for use in the U.S. for the 2023-2024 influenza season, depending on the manufacturing method of the vaccine, the committee recommended that the A(H1N1)pdm09, A(H3N2) and B/Austria/1359417/2021-like virus (B/Victoria lineage) viruses recommended above for the quadrivalent vaccines be used.