Western officials, researchers cast doubt on China lab virus leak theory

Researchers in the US, UK and Australia published a paper in the journal Nature Medicine in mid-March that concluded: "Our analyses clearly show that SARS-CoV-2 (the virus that causes COVID-19) is not a laboratory construct or a purposefully manipulated virus."

The odds were extremely high against a lab release as opposed to a natural event, said Kristian Andersen, the lead author of the paper and a specialist in infectious diseases at the Scripps Research Translational Institute in California, The New York Times reported.

Jonna Mazet, an epidemiologist at the University of California, Davis, who has worked with and trained researchers at the Wuhan Institute of Virology in the past, said a lab accident was "highly unlikely".