The World Health Organization (WHO) today announced its recommendations for the viral composition of influenza (or ‘flu’) vaccines for use in the 2027 southern hemisphere influenza season. The announcement was made following an international consultation on the composition of influenza virus vaccines.

Seasonal influenza causes substantial illness and many hospitalizations each year. Regular updates to vaccine composition are needed because influenza viruses continually evolve. WHO’s recommendations are used by national vaccine regulatory agencies and pharmaceutical companies around the world to develop, produce, and license influenza vaccines for the following influenza season. This ensures that vaccines are closely matched to the viruses expected to circulate, offering the best possible protection against severe illness and death.

Twice each year, WHO convenes experts from its Collaborating Centres and Essential Regulatory Laboratories to review surveillance data generated through the Global Influenza Surveillance and Response System (GISRS) and other sources, and recommend vaccine compositions for upcoming influenza seasons.