Who Can Declare a Pandemic and What Criteria Are Required for an Outbreak to Be Called a Pandemic?: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Photos

Two health care workers in yellow protective gowns, masks, and gloves administer a COVID-19 test to a person inside a car at a drive-in testing center.

See All Images →

Topics

pandemic outbreak Is It Safe to Reopen Schools During the COVID-19 Pandemic?Influenza Pandemic of 1918–19 Chart What Is a Second Wave of a Pandemic, and Could It Happen for COVID-19?How Long Did the Flu Pandemic of 1918 Last?When Was the Last Pandemic?U.S. Death Toll During Major Events Why Are Cruise Ships Prone to Outbreaks?How Did the COVID-19 Pandemic Start?Today in History—June 24: The Outbreak of the Dancing Plague