A pandemic can occur when a new influenza A virus is able to easily infect and spread among people.
CDC plays an important role in helping to establish, maintain, and expand flu surveillance.
National, state and local pandemic planning and response tools
Learn about CDC's global flu programs and CDC's work to protect the United States and the world.
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Pandemic Vaccine Targeting Guidance leads U.S. preparedness and response in a flu pandemic.
Past descriptions and report summaries for influenza A viruses assessed by the IRAT