Facebook Twitter Tumblr Close Skip to main content
A Project of The Annenberg Public Policy Center
SciCheck’s COVID-19/Vaccination Project

What do we know about the origins of SARS-CoV-2?

This article is available in both English and Español

The scientific consensus is that the SARS-CoV-2 virus, which causes the disease COVID-19, occurred naturally and was likely developed in bats before transferring to humans, either directly or through another animal. The World Health Organization explains that SARS-CoV-2 is “closely related genetically to coronaviruses isolated from bat populations.” Researchers in Chinathe U.S. and elsewhere have said the virus shares 96% of its genome with a bat virus.

As the Centers for Disease Control and Prevention says, coronaviruses “are a large family of viruses that are common in people and many different species of animals, including camels, cattle, cats, and bats.” Typically, an animal coronavirus doesn’t infect people, but this transfer from animals to humans — called zoonotic transfer — occurred with two other coronavirus outbreaks, SARS in 2003 and MERS in 2012.

An article published in Nature Medicine in March 2020 found that SARS-CoV-2 “is not a laboratory construct or a purposefully manipulated virus,” contrary to viral misinformation and conspiracy theories. The authors, who analyzed genomic data, said that the virus likely originated through “natural selection in an animal host before zoonotic transfer,” or “natural selection in humans following zoonotic transfer.”

The authors said an accidental laboratory release of the naturally occurring virus can’t be ruled out, but they “do not believe that any type of laboratory-based scenario is plausible.”

The earliest known human cases of the disease occurred in late 2019 in Wuhan, ChinaChinese officials reported an outbreak of mysterious pneumonia cases to the WHO on Dec. 31, 2019.