The World Health Organization (WHO) today announced its recommendations for the viral composition of influenza vaccines for use in the 2026 influenza season in the southern hemisphere.
The WHO wrote on September 26, 2025, that given the constantly evolving nature of influenza viruses, regular updates to vaccine composition are essential to ensure their effectiveness and to protect public health worldwide.
WHO recommends that trivalent vaccines for use in the 2026 southern hemisphere influenza season contain these ingredients. Quadrivalent vaccines, where the transition to trivalent vaccines is not yet complete, include a 4th component – a B/Yamagata lineage virus (B/Phuket/3073/2013-like virus).
Consistent with the four previous WHO recommendations since September 2023, the WHO influenza vaccine composition advisory committee remains of the opinion that the inclusion of a B/Yamagata lineage antigen is no longer warranted.
The WHO has also updated recommendations for the development of new candidate vaccine viruses for zoonotic influenza, with a view to pandemic preparedness.
WHO’s recommendations serve as the basis for national and regional regulatory authorities, pharmaceutical manufacturers, and other stakeholders to develop, produce, and license influenza vaccines for the upcoming season.