The World Health Organisation (WHO) has announced its recommendations for the viral composition of influenza vaccines for the 2025-2026 influenza season in the northern hemisphere.
This announcement was made during an information session after a four-day meeting on the Composition of Influenza Virus Vaccines, a gathering that occurs biannually.
WHO organises these consultations with an advisory group of experts drawn 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 national vaccine regulatory agencies and pharmaceutical companies to develop, produce and license influenza vaccines for the upcoming influenza season.
Periodic updates of the viruses contained in influenza vaccines are essential for maintaining vaccine effectiveness, given 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 include 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 for a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.
