Global Virus Surveillance

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Global surveillance of the influenza virus is accomplished by a network of approximately 200 World Health Organization (WHO) laboratories in 79 countries. The work of these laboratories is coordinated by four WHO Influenza Collaborating Centers in Atlanta, London, Melbourne, and Tokyo. The Centers for Disease Control and Prevention (CDC) in Atlanta is one of the WHO Collaborating Centers. Through this collaborative network, influenza viruses are isolated from sick people worldwide throughout the year. Samples of the viruses are sent to the Influenza Collaborating Centers for further testing. Information from the surveillance system is used to make recommendations about which strains of influenza virus are likely to circulate in the coming year. Vaccine manufacturers then use these strains to make your annual influenza vaccine. Typically, each year, three strains of influenza viruses are in the vaccine, two strains of influenza A and one strain of influenza B. The global network also serves as an early warning should a potential new pandemic strain arise.

WHO Collaborating Centers for Influenza Worldwide Map