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expert reaction to a preprint reviewing the evidence on the origins of SARS-CoV-2

A preprint, an unpublished non-peer reviewed study, critically reviews the current scientific evidence on the origins of SARS-CoV-2.


Please note this is a comment from one of the authors, NOT a third party comment, but sending out in case useful as there wasn’t a press release: Prof David L Robertson, MRC Investigator, Head of CVR Bioinformatics MRC-University of Glasgow Centre for Virus Research (CVR), said:

In a review of the evidence as a group of experts in virus evolution and molecular virology we concluded the most parsimonious explanation for the origin of SARS-CoV-2 is a zoonotic spillover event. The contact tracing of early cases in Wuhan, obtained from the WHO report earlier this year, exhibits striking similarities to the early spread of the first SARS-virus, where humans infected early in the epidemic lived near or worked in animal markets. While the intermediate animal species has not been found, there is clear evidence of susceptible animals being present in the Wuhan market throughout 2019, and related viruses have been found circulating in horseshoe bats, again very similar to the first SARS-virus. Altogether the evidence points to a zoonotic event and not a leak from a laboratory in Wuhan. The “lab leak” scenario alternates between it was made in a lab and it was an accidental release of a natural virus, neither of which there’s any evidence for. It’s of critical importance to understand the origin of SARS-CoV-2 so we can assess the risk of future spillover events.”


Prof James Wood, Head of Department of Veterinary Medicine, University of Cambridge, said:

“This manuscript represents a very considered review of all virological and epidemiological evidence regarding the origins of the cause of the COVID-19 pandemic, SARS-COV-2. The authors, who are acknowledged experts in their fields, concluded that there is a substantial body of scientific evidence supporting a zoonotic origin for SARS-CoV-2.

“They considered the uncertainties that invariably persist around retrospective investigations of this nature and also noted that a laboratory accident could not be entirely ruled out, but that this was highly unlikely relative to an origin involving human and animal contact.

“While nothing can be absolutely certain regarding the origin of the pandemic, it is important that we note the conclusions of this review and start to act to introduce changes that can reduce the likelihood of further events occurring. Regulation of laboratory experimentation will not do this. Trade in and markets for live animals, especially involving the mixing of wildlife species need banning or tightly regulating and we should work to reduce biodiversity loss, an important underlying driver for zoonotic disease emergence. Biodiverse areas should be protected, recognising that humans are an important part of biodiversity; recognising land rights of indigenous peoples can make important contributions to protecting ecoystems.”


Dr Jonathan Stoye, Group Leader, Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, said:

“The debate about the origins of SARS-CoV-2 is becoming increasingly acrimonious.  The failure to detect a potential natural host has stimulated suggestions by some that the COVID-19 pandemic has resulted from the escape of an engineered virus from a lab in Wuhan, China. However, there is little or no evidence for such an event and lab leak theories remain essentially speculative, at times verging on conspiratorial. 

“By contrast, the current preprint provides a refreshingly clear and reasoned description of the virological events that have taken place during the emergence of the pandemic virus. It makes a strong case for the natural origin of the virus followed by on-going adaptation in humans.  The continuing evolution of the virus to give new variants, highlighted by the independent acquisition of the N501V change on multiple occasions, is clearly inconsistent with the notion of a purposely manipulated virus optimized for growth on human cells. While there are still gaps in our knowledge that should be explored further, particularly regarding events that occurred before December 2019, the conclusions reached here seem entirely consistent with those in the WHO report released earlier this year.”



‘The Origins of SARS-CoV-2: A Critical Review’ by Edward Holmes et al. is a preprint available here:



All our previous output on this subject can be seen at this weblink:



Declared interests

Prof David L Robertson: “Prof David L Robertson is an author on the paper – this is not an independent third party comment.”

Dr Jonathan Stoye: “No interests to declare.”

None others received.

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