WHO announces recommendations for influenza vaccine composition in 2025

The World Health Organization (WHO) has announced recommendations on the viral composition of influenza vaccines for the 2025 influenza season in the southern hemisphere. The international organization holds two annual meetings to determine this composition: one for the southern hemisphere, the other for the northern hemisphere. It brings together experts from WHO collaborating centres, key regulatory laboratories and community surveillance and response centres.

These recommendations are used by national vaccine regulatory agencies and manufacturing companies to develop, manufacture and license influenza vaccines for the upcoming season.

WHO has recommended that trivalent vaccines used during the influenza season contain the following: For egg-based vaccines, a virus similar to A/Victoria/4897/2022 (H1N1)pdm02; A/Croatia/10136RV/2023 (H3N2)-like virus and B/Austria/1359417/2021-like virus (B/Victoria lineage).

For cell culture, recombinant protein or nucleic acid based vaccines: virus similar to A/Wisconsin/67/2022 (H1N1) pdm09; A/District of Columbia/27/2023 (H3N2)-like virus and B-like virus (Austria/1359417/2021 (B/Victoria lineage).

Finally, the recommendation for the B/Yamagata lineage quadrivalent influenza vaccine component remains unchanged from previous recommendations, which included a virus similar to B/Phukey/3073/2013 (B/Yamagata lineage).