"There is no evidence that SARS-CoV-2, the virus that causes COVID-19 in humans, originated in a laboratory in Wuhan, China.
"Coronaviruses like SARS-CoV-2 are commonly found in wildlife species and frequently jump to new hosts. This is also the most likely explanation for the origin of SARS-CoV-2.
"The closest known relative of SARS-CoV-2 is a bat virus named RaTG13, which was kept at the Wuhan Institute of Virology. There is some unfounded speculation that this virus was the origin of SARS-CoV-2. However:
(i) RaTG13 was sampled from a different province of China (Yunnan) to where COVID-19 first appeared; and
(ii) the level of genome sequence divergence between SARS-CoV-2 and RaTG13 is equivalent to an average of 50 years (and at least 20 years) of evolutionary change.
"Hence, SARS-CoV-2 was not derived from RaTG13.
"In addition, we know that viruses related to SARS-CoV-2 are also found in pangolins. This suggests that other wildlife species are likely to carry relatives of SARS-CoV-2.
"In summary, the abundance, diversity and evolution of coronaviruses in wildlife strongly suggests that this virus is of natural origin. However, a greater sampling of animal species in nature, including bats from Hubei province, is needed to resolve the exact origins of SARS-CoV-2."
Professor Edward Holmes is an Australian Research Council Laureate Fellow, a Fellow of the Australian Academy of Science and a Fellow of the Royal Society in London.
He has published six academic papers this year on the genome and origin of SARS-CoV-2, the virus that causes COVID-19 in humans.
At the University of Sydney he is a member of the Charles Perkins Centre and the Marie Bashir Institute for Infectious Diseases and Biosecurity. He holds a joint position with the School of Life and Environmental Sciences and the Sydney Medical School.