An influenza pandemic (PDF) is a world-wide outbreak of a new flu virus that spreads rapidly from one country to another. Because the virus is new, people have no natural immunity to it. Without a vaccine or immunity, the virus passes rapidly from person to person. Hundreds of thousands of people in our country could get sick and many could die.
The most recent pandemic in the United States is the COVID-19 coronavirus. For more information about this and prior pandemics, click on the links below.