The World Health Organization (WHO) on March 11 declared COVID-19 a pandemic, pointing to the over 118,000 cases of the coronavirus illness in over 110 countries and territories around the world and the sustained risk of further global spread.
“This is not just a public health crisis, it is a crisis that will touch every sector,” said Dr. Tedros Adhanom Ghebreyesus, WHO director-general, at a media briefing. “So every sector and every individual must be involved in the fights.”
An epidemic refers to an uptick in the spread of a disease within a specific community. By contrast, the WHO defines a pandemic as global spread of a new disease, though the specific threshold for meeting that criteria is fuzzy. The term is most often applied to new influenza strains, and the CDC says it’s used when viruses “are able to infect people easily and spread from person to person in an efficient and sustained way” in multiple regions. The declaration refers to the spread of a disease, rather than the severity of the illness it causes.
In some ways, declaring a pandemic is more art than science. “Pandemics mean different things to different people,” National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci said in February. “It really is borderline semantics, to be honest with you.”
During multiple prior press briefings, WHO officials maintained that COVID-19 had “pandemic potential,” but stopped short of declaring it one. The agency did, in January, call it a public health emergency of international concern, a slightly different label that refers to an “extraordinary event” that “constitute[s] a public health risk to other States through the international spread of disease.”
“Pandemic is not a word to use lightly or carelessly. It is a word that, if misused, can cause unreasonable fear, or unjustified acceptance that the fight is over, leading to unnecessary suffering and death,” said Dr. Tedros on March 11. “Describing the situation as a pandemic does not change WHO’s assessment of the threat posed by this coronavirus. It doesn’t change what WHO is doing, and it doesn’t change what countries should do.”
SARS-CoV-2, the virus that causes COVID-19, is thought to have first jumped from an animal host to humans in Wuhan, China. At least at first, most cases were seen within China and among people who had traveled there, as well as those travelers’ close contacts. While these cases were concerning, they did not suggest a pandemic, because there was not significant spread outside of China.