The World Health Organization (WHO) today announced recommendations for the viral composition of influenza (or “flu”) vaccines for the 2026-2027 northern hemisphere influenza season. The announcement was made following a 4-day consultation examining global influenza surveillance data. 

Influenza vaccine composition must be regularly updated because influenza viruses are constantly changing. 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.   

Held twice a year, once each for the northern and southern hemispheres, these consultations bring together experts from WHO’s Collaborating Centres and Essential Regulatory Laboratories of the WHO Global Influenza Surveillance and Response System (GISRS) to review and analyze data generated by GISRS and partners.