The scientific consensus has been that the two viruses are unlikely to be the same, with some estimates suggesting it could take between 20 and 50 years to make up the 4 per cent genetic difference.
The Independent employs reporters around the world to bring you truly independent journalism. To support us, please consider a contribution.
Scientists have raised fresh questions over whether a coronavirus sample held for years in a Wuhan laboratory could have mutated naturally or via genetic experimentation to become the virus which causes Covid-19.
Since the Sars pandemic in 2003, China-based researchers have been scouring bat-inhabited caves in the hope of tracking and analysing potential new coronaviruses, notably at the Wuhan Institute of Virology (WIV).
Among the most revered of these scientists is Dr Shi Zhengli, nicknamed “Bat Woman” by her colleagues – who in February co-authored the most extensive academic paper on the novel coronavirus up to that point.
In addition to giving a full genetic description of the virus, Dr Shi’s paper – published in Nature – revealed that the WIV housed a sample of virus collected from bats named RaTG13, which it said was a 96.2 per cent match with the Covid-19 virus – the closest yet discovered.
However, past research work carried out at VIW to improve the ability of pathogens to cause disease, known as “gain-of-function” research, has been documented in papers published between 2015 and 2017, described in one paper co-authored by Dr Shi as “virus infectivity experiments”.
While scientists also overwhelmingly believe the genetic code of Sars-Cov-2 suggests it has mutated naturally, and has not been engineered, others believe it should not be ruled out that the two viruses may once have been the same.
The type of techniques required to turn RaTG13 into Sars-Cov-2 are “identical” to work previously carried out in Wuhan, alleges Professor Richard Ebright of Rutgers University’s Waksman Institute of Microbiology in New Jersey.
“The very same techniques, the very same experimental strategies using RaTG13 as the starting point, would yield a virus essentially identical to Sars-Cov-2,” he told The Sunday Times.
However, Professor Martin Hibberd of the London School of Hygiene & Tropical Medicine contended that to do so would be “exceptionally difficult”, telling the paper that they “are not the same virus and I don’t think you can easily manipulate one into the other”.
No hype, just the advice and analysis you need
The pair also disagreed over how long the necessary mutation would take naturally.
Prof Hibberd suggested it could take around 20 years to do so, but Prof Ebright said it was “not a valid assumption” to assume that the virus would have developed at the rate observed since its emergence this year.
“When a virus changes hosts and adapts to a new host the rate of evolutionary change is much higher,” Prof Ebright said.
“And so it is possible that RaTG13, particularly if it entered humans prior to November 2019, may have undergone adaptation in humans at a rate that would allow it to give rise to Sars-Cov-2. I think that is a distinct possibility.”
The origins of the RaTG13 sample held have also been placed under further scrutiny, with one of Dr Shi’s longstanding colleagues alleging that it was found in 2013 in a Chinese copper mine linked to the deaths of three men tasked with clearing bat faeces.
While the cause of their deaths was linked to fungus found in the cave, tests carried out on four of the men found they all had antibodies against an unknown Sars-like coronavirus.
In 2012, Dr Shi and her team were reportedly called to the copper mine near Tongguan in the Mojiang region after six men fell ill with pneumonia-like symptoms.
In a paper called “Coexistence of multiple coronaviruses in several bat colonies in an abandoned mineshaft” published in 2016, she and her colleagues wrote that of the 152 genetic sequences of coronavirus found in the mine, two were similar to that which had caused Sars. One was reportedly described as a “new strain” of Sars and called RaBtCoV/4991.
In claims backed up by a virus database published by the Chinese Academy of Sciences, Peter Daszak, president of EcoHealth Alliance, who has searched for viruses with Dr Shi’s team for 15 years told The Sunday Times that the sample found in the mine, RaBtCoV/4991, had been renamed RaTG13, adding: “It was just one of the 16,000 bats we sampled.
“It was a faecal sample, we put it in a tube, put it in liquid nitrogen, took it back to the lab. We sequenced a short fragment.”
Referencing the sample’s change of name since its discovery in 2013, he said: “The conspiracy folks are saying there’s something suspicious about the change in name, but the world has changed in six years – the coding system has changed.”
While it is reported that what is believed to be the closest-known relation to the novel coronavirus was shelved in the Wuhan institute at that point as not being a close enough match to the Sars virus, scientists have questioned the likelihood of this scenario.
“If you really thought you had a novel virus that had caused an outbreak that killed humans then there is nothing you wouldn’t do – given that was their whole reason for being [there] – to get to the bottom of that, even if that meant exhausting the sample and then going back to get more,” Nikolai Petrovsky of Flinders University in Adelaide told The Sunday Times.