Animal spillover? Lab leak? What the science says about the origins of COVID-19

Global Health Animal spillover? Lab leak? What the science says about the origins of COVID-19 July 29, 20267:02 PM ET By  Rachel Carlson Members of the Wuhan Hygiene Emergency Response Team leave the shuttered Huanan Seafood Wholesale Market in the city of Wuhan, in Hubei, Province on January 11, 2020. Investigations of the origin of COVID-19 have centered on the animals sold at the market. Noel Celis/AFP/via Getty Images hide caption toggle caption Noel Celis/AFP/via Getty Images Sen. Rand Paul, R-Ky., faced off with leading COVID-era infectious diseases specialist Dr. Anthony Fauci during a Senate hearing today, bringing renewed attention to ongoing debates about the origins of the coronavirus that caused the pandemic. Fauci, who directed the National Institute of Allergy and Infectious Diseases from 1984 to 2022, has long supported the theory that the virus jumped from animals to humans. Paul and the Trump administration say that the virus leaked from a Chinese laboratory, either accidentally or intentionally. In 2025, the Trump administration took down some government websites providing COVID-19 information and replaced them with a page called "LAB LEAK: The True Origins of COVID-19," dedicated to the controversial theory. Sponsor Message The lab in question, the Wuhan Institute of Virology, is located in the city where the first cases of COVID were recorded. What does the evidence show? Supporters of what's now known as the "lab leak" theory note that the analysis of the virus by scientists relied on incomplete data provided by the Chinese government. They also point to the lack of a smoking gun in previous analyses — an animal infected with SARS-CoV-2, the virus that causes COVID-19, at a market in Wuhan, China. Some U.S. intelligence agencies have also expressed a low-to-moderate degree of confidence in the accidental lab leak theory. But virologists who study pandemic origins are much less divided than the U.S. intelligence community. They say there is...