WHO announces 2027 influenza vaccine composition recommendations

The World Health Organization (WHO) has announced the recommended composition for seasonal influenza vaccines for the 2027 season in the southern hemisphere. Following months of international consultation and data analysis from the Global Influenza Surveillance and Response System (GISRS), the WHO has moved toward a trivalent vaccine standard, as the B/Yamagata lineage is no longer circulating significantly.

For egg-based vaccines, the recommended strains include an A/Missouri/11/2025 (H1N1)-like virus, an A/Darwin/1454/2025 (H3N2)-like virus, and a B/Tokyo/EIS13-175/2025 (Victoria lineage)-like virus. For vaccines produced using cell culture, recombinant proteins, or nucleic acids, the recommendations include the same type A strains with slight variations in the H3N2 component, alongside a B/Pennsylvania/14/2025 (Victoria lineage)-like virus.

These updates are critical for national regulatory authorities and pharmaceutical companies to ensure vaccines match circulating viruses, providing optimal protection for vulnerable populations such as the elderly and young children. Recent data indicates that influenza A viruses have been more prevalent globally, though type B viruses have shown higher prevalence in parts of North and West Africa and East Asia.