The World Health Organisation (WHO) today announced the recommendations for the viral composition of influenza vaccines for the 2025–2026 influenza season in the northern hemisphere. The announcement was made at an information session at the end of a 4-day meeting on the Composition of Influenza Virus Vaccines, a meeting that is held twice annually. 

WHO organises these consultations with an advisory group of experts gathered from WHO Collaborating Centres and WHO Essential Regulatory Laboratories to analyse influenza virus surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS). The recommendations issued are used by the national vaccine regulatory agencies and pharmaceutical companies to develop, produce, and license influenza vaccines for the following influenza season. 

The periodic update of viruses contained in influenza vaccines is necessary for the vaccines to be effective due to the constantly evolving nature of influenza viruses, including those circulating and infecting humans.

The WHO recommends that trivalent vaccines for use in the 2025–2026 northern hemisphere influenza season contain the following: 

Egg-based vaccines

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

Cell culture, recombinant protein or nucleic acid-based vaccines

• A/Wisconsin/67/2022 (H1N1)pdm09-like virus
• A/District of Columbia/27/2023 (H3N2)-like virus
• 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.

•  B/Phuket/3073/2013 (B/Yamagata lineage)-like virus