COVID-19: nine lives of the laboratory leak hypothesis

DAt the start of the pandemic, the idea was proposed that SARS-CoV-2, the virus that causes COVID-19, was a product of manipulation by a Chinese laboratory. I must say that the presence in the Chinese city of Wuhan, where the virus appeared in the fall of 2019, of a large Institute of Virology for Maximum Safety (WIV), which has been working with coronaviruses, has something to do with this. stir up suspicions. However, already in March 2020 in Nature – Medicine presented an analysis of the genetics of SARS-CoV-2 that contradicts this hypothesis. Without formally excluding the possibility that the virus could acquire its characteristics in cell cultures – “theoretically possible,” the authors admitted – the study concluded that natural origins were much more likely. For a while, this article seemed to close the discussion, even though some, while staying in the margins, continued to adhere to the thesis of a laboratory accident. We add that a few months ago, the WHO investigation also concluded that such a possibility is “extremely unlikely.”

But this thesis suddenly came to life for two or three weeks. This is a bit surprising since no new or compelling fact has been discovered since then, but let’s take a look at some of the main elements that brought this idea to the fore.

May, 23rd, Wall street journal published an article based on a U.S. intelligence report that states that three WIV employees were hospitalized in November 2019 with symptoms similar to COVID-19. China denies the facts, but hey, it’s obviously hard to believe such an opaque regime in his words. But even if we assume that this is true, this proves little: it is not known what these people got sick – it could be the flu or many other respiratory diseases. The fact that three employees of the institute, which employs hundreds of people, simultaneously become infected with the microbe is not in itself exceptional or suspicious. In addition, the Wall Street Journal points out that the US intelligence report appears to have been written “in the last days of the Trump administration,” which often echoes the idea that COVID-19 was artificially produced. Given his interest in promoting this thesis and his freedom of fact, the credibility of this source is undermined.

On May 26, President Biden’s chief medical adviser, Anthony Fauci, said he was “not 100% convinced” that COVID-19 is of natural origin. It made headlines and caught many by surprise, giving the impression that Dr. Fauci had flipped his jacket – someone who was very clearly leaning towards the idea of ​​jumping from animal to human in 2020. Full quote, everyone understands that their “new” position is not much different from the “old”, ultimately: “The historical background supporting the idea that pandemics naturally evolve from an animal reservoir is extremely strong. And it is for this reason that we believe the likelihood that something like this happened. [dans le cas de la COVID-19] a lot more. But no one knows, not even me, 100% at this time, so we are in favor of further investigation. [ndlr : commandée plus tôt par l’administration Biden]… “

In mid-May, several researchers signed an open letter to The science stating that WHO was too strong in their opinion and that an investigation should be continued. They rightly point out that the natural origin has not yet been officially proven, but they do not cite any new facts.

Also in May, Nobel Prize for Medicine, David Baltimore, said that he believed that the features of the genetic sequence of COVID-19, called the “furin cleavage site”, were “irrefutable proof” in his eyes (smoking gun) that the virus was artificially created. Basically, his argument is that the protein that allows SARS-CoV-2 to attach to human cells does not initially work: after initial assembly, it must be “cleaved” in two places by an enzyme (furin). activated. This is a trait that is missing from the closest known relative of COVID-19, RaTG13, a virus found in some species of bats in China. This, along with some other features of SARS-CoV-2, convinced Baltimore of the artificial origin of the new coronavirus.

Critical experts

However, he clearly did not convince many other experts who were highly critical – see, in particular, this thread of tweets microbiologist Christian G. Andersen of the Scripps Research Institute (California). This “furin cleavage site” is indeed seen in many other coronaviruses unrelated to SARS-CoV-2, indicating that it may well occur naturally. And this is not an entirely new argument, since since the summer of 2020, research (including on natural origin) has been talking about it in Archive of Virology and in the French scientific review medicine / science

In short, in recent weeks we have heard about the alleged “laboratory leak” mostly “noise” since not the slightest convincing element has been added to what we already knew. Researcher-virologist at the University of Laval, Sylvain Moineau, saw nothing in all this that could convince him of a different origin than natural. “I have problems with these stories,” he says, “because there are usually risk management committees that do laboratory audits. we [ndlr : une «collection» de virus dont il a la charge], we have a level 2 confinement [ndlr : sur une échelle de 4] and they come regularly to see if we are following security protocols. What we know about coronaviruses is that this is how they usually get to humans, from bats to intermediate species. So it makes sense to think that until proven guilty, this is exactly what should have happened with SARS-CoV-2, ”he says. Add to that the testimony of several Western virologists who have visited the WIV in the past and confirmed the rigor of its security measures.

It’s the same story with Pierre Talbot, a virologist at the Armand-Frappier Institute. “I don’t think this virus was human-made, it’s too complex,” he says. Its genome has 30,000 base pairs. [ndlr : le génome est fait un peu comme une chaîne, et celui de la COVID-19 fait 30 000 «maillons» de long], which means that many hazards can occur during construction. Some parts may not be compatible with others, and one altered base pair can cause all sorts of effects. Therefore, I am very skeptical that this virus could have been developed in a laboratory. “

The fact remains: we still haven’t found the famous “intermediate species” that would help the virus move from the bat (whose cells are too different from ours for the virus to be transmitted directly to humans) to us, ”he admits. Moino. “When there were episodes of SARS (2002-2003) and MERS (2012), it took only a few months to find 99% of an identical mediator in another mammal. But in the case of SARS-CoV-2, we still haven’t found it, so it becomes fertile ground for the imagination, ”he says.

By comparison, RaTG13 is “only” 96% identical to COVID-19, which means that its last common ancestor with SARS-CoV-2 dates back to sometime in the second half of the 20th century. All this time, the virus must have evolved into a different species of mammal, but has not yet been identified. Some “pieces” of its genome are very close to the coronavirus found in pangolin, but this discovery did not lead to the discovery of a virus identical enough to COVID-19 to stop the search for this known intermediate species.

Therefore, we cannot formally rule out the presence of a laboratory, at least not yet. But in general, nature has all the tools it needs to make viruses like SARS-CoV-2. Coronaviruses are known to fuse in nature, and COVID does seem like a jigsaw puzzle that includes several pieces of other coronaviruses. So until we find real evidence of artificial origin – and not just weak circumstantial evidence such as the presence of WIV in Wuhan – the most likely hypothesis will certainly remain the same. Spontaneous “jump” from animal to animal. human.

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