The periodic replacement of viruses contained in influenza vaccines is necessary in order for the vaccines to be effective due to the constantly evolving nature of influenza viruses, including those circulating and infecting humans.
Twice annually, WHO organizes consultations with an advisory group of experts to analyse influenza virus surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS), and issues recommendations on the composition of the influenza vaccines for the following influenza season. These recommendations are used by national vaccine regulatory agencies and the pharmaceutical companies to develop, produce and license influenza vaccines.
27 February – 1 March 2017, Geneva, Switzerland