WHO Announces Vaccine Recommendations

The World Health Organization (WHO) published its recommendations for the viral composition of influenza vaccines for the 2025–2026 northern hemisphere influenza season. The announcement follows a four-day meeting of the WHO Advisory Group on the Composition of Influenza Virus Vaccines, which convenes twice annually to assess global influenza virus surveillance data. 

“The periodic update of vaccine composition is necessary to maintain effectiveness, as influenza viruses constantly evolve,” states the organization. To assess recommendations, a group of experts analyze surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS). This helps regulatory agencies and pharmaceutical companies develop, produce, and license vaccines for the next season. WHO's recommended strains for trivalent vaccines in the 2025–2026 northern hemisphere influenza season are:

For 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

For 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 B/Yamagata lineage component in quadrivalent influenza vaccines remains unchanged, still including the B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

The WHO's vaccine strain selection is based on a review of global influenza surveillance data, including virus prevalence, genetic and antigenic characteristics, and epidemiological trends. The organization aims to ensure that vaccines provide the best possible protection against influenza infections by selecting strains that are most likely to circulate in the upcoming season.

Following WHO’s recommendations, vaccine manufacturers and national health authorities will proceed with vaccine production and regulatory approvals. The influenza vaccine composition for the southern hemisphere is reviewed separately in a similar process conducted later in the year.