On Sept. 27, 2024, the World Health Organization (WHO) announced the recommendations for the viral composition of influenza vaccines for the 2025 influenza season in the southern hemisphere. The WHO recommends that trivalent vaccines for use in the 2025 southern hemisphere influenza season contain the following:

Egg-based vaccines 

• 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.

Cell culture-, recombinant protein- or nucleic acid-based vaccines

• 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 recommendation for the B/Yamagata lineage component of quadrivalent influenza vaccines remains unchanged from previous recommendations: a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.