The authors of the new work say that the chimeric experiments of 2015 also impacted sweet and bitter taste receptors and could explain why people lose their sense of taste during Covid.
They even speculate that, because the groups used cell lines from Henrietta Lacks – the African-American woman whose cancer cells are the source of the first immortalized human cell line – this may have allowed the virus to grow larger. infectious to black populations.
The paper concludes that several features of the coronavirus are “unlikely to be the result of natural evolution” and, taken together, point to “reasoned manipulation, specifically for gain of function”.
Others are less sure. Dr Jonathan Stoye, group leader of the retrovirus-host interactions laboratory at the Francis Crick Institute, says the virus’s rapid evolution makes an artificial explanation unlikely.
“It seems extremely unlikely, if not impossible, that changes spanning such an evolutionary distance could have occurred while the virus was growing in a lab,” he said.
“It is therefore very likely that the immediate ancestor of SARS-CoV-2 exists in the wild and remains to be found. “
Yet one thing is certain. Laboratory leaks have occurred several times before. In 2004, the Sars virus escaped from a high-containment research laboratory in Beijing at least three times, causing local epidemics.
Earlier this week, a U.S. intelligence report identified three researchers from a Wuhan laboratory who sought treatment at a hospital after falling ill in November 2019. A report from last May suggested there may be – to have had an emergency stop at the Wuhan Institute of Virology as early as October.
Joe Biden, the US President, has now given intelligence services three months to report on the origins of Covid – but that will depend on whether China opens up, which seems unlikely.
For now, all we have is a smoking gun, a mind-boggling death rate – and the unsettling feeling that there is more to this virus than meets the eye.