does the virus mutate naturally – or is the Wuhan lab really the cause?

Compare the two situations

The fact that Dr Shi manipulated the coronaviruses in arguably inadequate safety conditions sets up a plausible case that the SARS2 virus may have escaped from his lab. But this case lacks evidence, which, if it exists, is likely to be found in the sealed records of Dr Shi’s lab. Thus there is no direct evidence for natural occurrence or lab escape scenario. Without such evidence, the best approach is to take some obvious facts about the pandemic and ask which of the two situations provides the best explanation. Here are three such tests:

1. Beginning

The bats that carry the closest known relatives of SARS2 live in caves in Yunnan in southern China. If the pandemic first affected the people living around the caves, that would be more desirable for natural growth. But the 1,500km distance in Wuhan is broken, at one time of the year when bats go into hibernation. Under the natural emergence scenario, it is difficult to see how the virus emerged somewhere other than Wuhan, and then exploded in the city without leaving any sign of its true origin.

Under the lab escape scenario, the explanation was no struggle: researchers at the Wuhan Institute of Virology cooked up dangerous over-the-counter viruses in arguably inadequate survival conditions, and one escaped. .

2. Natural history

Viruses jumping into new hosts often take many hours, and many changes, before they can fully cure the new target species. This process is marked in detail for the SARS1 virus. But researchers looking for the same SARS2 adaptation process have made a surprising discovery. Since its first appearance, the SARS2 virus has been almost completely adapted to human cells and has hardly changed since.

This is difficult to explain in the natural state of emergence. But from the lab escape scenario this is very clear. The virus grows in humans incarnate in mice, so of course it is well adapted to humans from the start.

3. The Furin cleavage site

Without examining the anatomical details of the SARS2 virus, there is a small region of its spike protein, called the furin cleavage site, traced to 12 units of the 30,000-unit genome.

Usually a virus gains access like this by reuniting-the unintentional exchange of genomic units associated with a virus when both are invaded in the same cell But nothing else is known. sarbecovirus – that’s the family name of SARS2 – with this 12 -unit insert. A virus cannot usually acquire, by reassembling, an element that is not in its family.

Infiltration also contains intrinsic entities known as arginine codons, which are different commonly in humans but not in coronaviruses such as SARS2.

Proponents of natural evolution have argued that the virus could have acquired infiltration from human cells after human flight. Probably, but no one has yet found the infected human population where the virus can thrive in this way.

In the lab escape scenario, the insert is easy to explain. “Since 1992 the virology community has known that one surefire way to make the virus more lethal is to give it a furin cleavage site,” wrote Dr Steven Quay, an interested biotech entrepreneur. of the origin of SARS2. At least 11 such experiments have been published, including one by Dr Shi. And human-preferred arginine codons are routinely provided in lab kits, so they can be used by anyone synthesizing a 12-unit insert in the lab.

“When I first looked at the furin cleavage site in the virus sequence, with the arginine codons, I told my wife it was the smoking gun for the origin of the virus,” says David Baltimore, a renowned virologist and former president of California. Institute of Technology. “These features present a strong challenge to the idea of ​​a natural source for SARS2.”

Then who is at fault?

The lab escape scenario explains the realities of height much faster than natural floating. So let’s ask which actions need to be examined, if the virus has actually come out of a lab.

First in line was Dr Shi and his colleagues. They create dangerous low -level viruses and arguably unsafe conditions. True, they follow the same international standards as those used by virologists everywhere. But they should have done their own assessment of the risks they were running.

Second in line for reprimand is the Chinese authorities, who are doing everything they can to hide the nature of the tragedy and their responsibility for it.

Third are virologists around the world who know more than anyone the dangers of curing natural viruses but cannot resist temptation. Their assurance that the benefits are real and the risks to be controlled is premature: the benefits are not visible and the risk, if SARS2 escapes from a lab, is disaster.

What needs to happen now? The Chinese authorities have no pressure to open their records because, to this day, the world media continues to accept the natural phenomenon of emergence. China will stop to get a free ride if credible scientific bodies such as the Royal Society and the U.S. National Academy of Science, separately or together, appoint expert groups to investigate the same origin scenarios. A strong conclusion of this and other institutions in agreement to investigate the origin of the virus for the first time put the task of China to cooperate.

Given the nature of authoritarian states, China cannot easily provide an evolving new perspective on the origin of the pandemic. Yet the hope of becoming the world’s pariah for a thoughtful future can be a way to prevent further stoning.

Nicholas Wade has worked at Nature, Science and the New York Times. He is the author of Where Covid-19 Came From, which comes from the Encounter Book

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