Origin story of COVID virus rewritten, challenging lab leak theory

West Australian

08-05-2025

New research is rewriting the origin story of the virus that triggered the deadly COVID pandemic.
Challenging the idea that the pandemic was caused by a lab leak, scientists now believe they know when and where the virus first emerged.
COVID, which first emerged in humans in Wuhan in central China in December 2019, is calculated to have caused up to 36 million deaths worldwide.
It's believe the virus that causes it left the area where it first emerged among animals in China or northern Laos several years before jumping across to humans 2700 kilometres away in Wuhan.
While the primary host of the virus was a horseshoe bat, the virus was only able to travel the distance to where the human cases were first detected by 'hitching a ride' there with other animals via the wildlife trade, according to the research published in
Cell
.
Researchers from the University of California San Diego School of Medicine made the finding after analysing the family tree of virus strains SARS-CoV-1, which caused the SARS pandemic of 2002-2004, and the SARS-CoV-2, which caused the COVID pandemic — mapping their evolutionary history before they emerged in humans.
'We show that the original SARS-CoV-1 was circulating in Western China — just one to two years before the emergence of SARS in Guangdong Province, South Central China, and SARS-CoV-2 in Western China or Northern Laos — just five to seven years before the emergence of COVID-19 in Wuhan,' researcher Jonathan E. Pekar said.
Given the distances that both viruses would have had to cover so quickly, it is highly improbable that they could have been carried there via the bats alone, they concluded.
Much more likely, they say, is that they were transported there accidentally by wild animal traders via intermediate host animals.
'The viruses most closely related to the original SARS coronavirus were found in palm civets and raccoon dogs in southern China, hundreds of miles from the bat populations that were their original source,' said co-senior author Michael Worobey.
'For more than two decades the scientific community has concluded that the live-wildlife trade was how those hundreds of miles were covered. We're seeing exactly the same pattern with SARS-CoV-2.'
The findings challenge the view that SARS-CoV-1 emerged naturally, but SARS-CoV2 was the result of a lab leak.
'At the outset of the COVID-19 pandemic, there was a concern that the distance between Wuhan and the bat virus reservoir was too extreme for a zoonotic origin,' co-senior author Joel Wertheim said.
'This paper shows that it isn't unusual and is, in fact, extremely similar to the emergence of SARS-CoV-1 in 2002.'
It's hoped that by continuing to sample wild bat populations for viruses, scientists will be able to prepare for and control future outbreaks.
Debate about the origins of COVID-19 has raged since the pandemic took hold in 2019-2020.
The CIA said in January the pandemic was more likely to have emerged from a lab in China than from nature, after the agency had for years said it could not reach a conclusion on the matter.