The World Health Organization (WHO) has announced its recommended viral composition for influenza vaccines to be used during the 2027 southern hemisphere influenza season, following an international consultation on influenza vaccine composition.
Seasonal influenza causes significant illness and hospitalisations each year. As influenza viruses continually evolve, vaccines need to be regularly updated to closely match the strains expected to circulate and help protect against severe disease and death.
WHO reviews global influenza surveillance data twice a year through its Global Influenza Surveillance and Response System (GISRS), with experts from WHO Collaborating Centres and Essential Regulatory Laboratories assessing circulating viruses and recommending vaccine compositions for upcoming seasons.
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From February to August 2026, influenza A(H1N1)pdm09, A(H3N2) and influenza B viruses circulated globally in varying proportions. Influenza A viruses were most common in most regions, while influenza B dominated in Northern and Western Africa, North America and Eastern Asia.
For egg-based vaccines, WHO recommends an A/Missouri/11/2025 (H1N1)pdm09-like virus, an A/Darwin/1454/2025 (H3N2)-like virus and a B/Tokyo/EIS13-175/2025 (B/Victoria lineage)-like virus.
“For nearly 75 years, the WHO Global Influenza Surveillance and Response System has demonstrated the power of global solidarity in public health,” said Dr Maria Van Kerhove, WHO’s Director for Epidemic and Pandemic Management. “The commitment of countries and laboratories to share data, viruses and expertise enables WHO to make timely vaccine recommendations, strengthening our collective ability to detect and respond to emerging influenza threats. This is global public health collaboration at its best.”
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For cell culture-, recombinant protein- or nucleic acid-based vaccines, the recommended composition includes A/Missouri/11/2025 (H1N1)pdm09-like, A/Darwin/1415/2025 (H3N2)-like and B/Pennsylvania/14/2025 (B/Victoria lineage)-like viruses.
WHO experts also reviewed zoonotic influenza viruses circulating in animals and selected candidate vaccine viruses that could support rapid vaccine production if a pandemic threat emerges.
