What does the science say about the origin of the Wuhan virus?

BBC asks, Coronavirus: Is there any evidence for lab release theory?

BBC answers, No. Not any, Not at all.

Is there any evidence of another source?

Yes, emphatically.

[A]lmost as soon as the novel coronavirus came to light, there was speculation - much of it uninformed - about its origins.

One online theory, that went viral in January, suggested the virus could have been engineered in a lab as a bioweapon. 

This allegation has been repeatedly dismissed by scientists, who note that studies show the virus originated in animals - most likely in bats.

Viruses can also be engineered for the purposes of fundamental scientific research. 

For example, gain of function studies may improve the ability of a pathogen to cause disease, to investigate how viruses could mutate in future.

But a US study of the coronavirus genome published in March found no signs it had been engineered. 

"By comparing the available genome sequence data for known coronavirus strains, we can firmly determine that SARS-CoV-2 originated through natural processes," co-author Kristian Andersen, from Scripps Research in California, said at the time.

Then there is the allegation of an accidental release of a natural virus from a lab. 

The proximity of the Wuhan seafood market, where the outbreak came to light, to at least two institutes carrying out research on infectious diseases fuelled speculation about a link.

That the WIV had carried out research on bat coronaviruses is a matter of public record. 

This work was entirely legitimate and published in international journals. Given the country's experience with the Sars outbreak in the early 2000s, this should come as no surprise.

Dr Lentzos [Dr Filippa Lentzos, a biosecurity expert at King's College London] said the issue of its origin was a "very difficult question", and added that "there have been quiet, behind-the-scene discussions... in the biosecurity expert community, questioning the seafood market origin that has come out very strongly from China".

But there is currently no evidence that any research institute in Wuhan was the source of Sars-CoV-2.