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About the Flu

What are the differences between seasonal flu, H1N1 (swine flu), H3N2v, and H5N1 (avian flu)?  In this section you will learn about each of these types of flu.

A woman blows her nose

Seasonal Flu

Learn when to expect seasonal flu, how it spreads, and how to protect yourself. Get information on who tracks cases to provide weekly flu activity reports in the United States.

A U.S. map includes the text 'Current United States Flu Activity Map'

Current Flu Season

View the current flu threat levels in the United States and around the world using an interactive map that tracks visits to health care providers for flu-like symptoms.

A syringe is shown with the caption 'H3N2' written below it.


Get information on H3N2v, how it spreads, who's monitoring it, and how to prevent it.

A female medical professional holds a bottle labeled H1N1

H1N1 (Swine Flu)

Get information on the status of H1N1 in the United States and how to prevent it. Learn how getting the seasonal flu vaccine is the best protection against H1N1.

An image of the H5N1 virus

H5N1 (Avian/Bird Flu)

Get information on the threat of H5N1, where it exists, and how it is spread. Learn how to avoid H5N1 flu if traveling, and how cases are monitored around the world.