"The
WHO Global Influenza Surveillance Network
Frequent updating of the influenza vaccine content is necessary as influenza viruses are permanently evolving. Only a vaccine whose virus strains match the circulating influenza viruses will protect recipients efficiently from influenza disease and death.
The WHO Influenza Surveillance Network serves also as a global alert mechanism for the emergence of influenza viruses with pandemic potential. Its activities have contributed greatly to the understanding of influenza epidemiology. The network was established in 1952, after a WHO Expert Committee recommended that through an international network of laboratories, WHO would be able to advise WHO Member States as to “what influenza control measures are useful, useless or harmful”."
Source:
WHO Global Influenza Surveillance Network website
Español: Red mundial de vigilancia de la gripe de la OMS
Français: Réseau mondial de surveillance de la grippe de l’OMS