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

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Written by
Kara Rogers
Kara Rogers is the senior editor of biomedical sciences at Encyclopædia Britannica, where she oversees a range of content from medicine and genetics to microorganisms. She joined Britannica in 2006 and...
Kara Rogers
Fact-checked by
The Editors of Encyclopaedia Britannica
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.
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Health care workers tend to patients at the drive-in center at ProHealth Care on March 18, 2020 in Jericho, New York. The facility offers COVID-19 testing as more than 200,000 people in at least 144 countries have been infected, with deaths in the....
Bruce Bennett/Getty Images

This article was originally published on March 18, 2020.

The World Health Organization (WHO) is responsible for declaring a pandemic. WHO monitors disease activity on a global scale through a network of centres located in countries worldwide and has a pandemic preparedness plan that consists of six phases of pandemic alert. Phase 1 represents the lowest level of alert and usually indicates that a newly emerged or previously existing virus is circulating among animals, with low risk of transmission to humans. Phase 6, the pandemic phase, is declared when an outbreak is characterized by globally widespread and sustained disease transmission among humans.