The pattern is deja vu: a scientific study appears among hundreds of others at the start of 2024. Going relatively unnoticed at first, an article posted online on January 4 on the BioRxiv website claims that a coronavirus discovered in pangolins captured in 2017, a cousin of Sars-CoV-2, was isolated and studied by scientists at Beijing University of Chemical Technology. The latter, which differs slightly from the virus present in nature due to its laboratory isolation, would have the capacity to infect human cells and humanized transgenic mice. The information was initially shared on X (formerly Twitter) by several conspiracy accounts before being taken up by the British newspaper Daily Mail. The information retained is the following: China manipulated a coronavirus, which would have given it much greater lethality. The machine is racing, the news is everywhere. And, Thursday January 18, it’s the turn of Figaro, in France, to take up this study. However, several elements of this article tend to minimize this “discovery”, to say the least.
For Florence Débarre, director of research in evolutionary biology at the CNRS and who has carried out several research on the origins of Sars-CoV-2, the presentation made of this study is “somewhat biased”. What are we talking about ? To put it simply, a pangolin coronavirus known as GX_P2V was isolated and studied by a Chinese team. Obviously, this is of concern because the trail of this animal had been mentioned as early as 2020 to explain the origins of Covid-19, before several studies showed that the closest virus was in reality circulating among bats in southern China. Worse, as written Le Figaro, we would observe “curious manipulations” which would have “favored the appearance of extremely pathogenic mutations on a coronavirus cousin of Sars-CoV-2”. China, the pangolin, a modified virus, the specter of a future pandemic… Don’t throw it away!
In reality, several research teams around the world – Chinese, of course, but also American or French – are studying two pangolin viruses seized in China in 2017 and 2019 and called GX/2017 and GD/2019. The date of the discovery of these viruses is not precisely known, the first study dating from 2020. Nothing new under the sun, therefore. The team from the Wuhan virology laboratory, led by Shi Zhengli, notably published work on this same coronavirus in February 2023, without it particularly stirring the crowds while his institute is at the heart of questions about the origins of the virus. Covid-19. In the United States, we also know that the team led by Ralph Baric, from the University of North Carolina, is studying the other pangolin coronavirus, that of 2019, even though it is closer to Sars-CoV- 2 than its 2017 cousin.
But let’s return to China, in 2024. The Beijing team would therefore have, according to these press articles, manipulated this pathogen. “The virus was isolated and studied by different groups, underlines Florence Débarre. To obtain the desired isolate, the researchers carried out different steps necessary for the isolation and purification of the virus. This means that the virus obtained in laboratory is not the same as the natural virus. It thus lost 104 nucleotides, which is not a lot in the end.” This makes the various media say that this modification of the genome, the result of a classic research process, is reminiscent of “gain of function” experiments (Editor’s note: these experiments aim to force the evolution of a virus by repeating infections on laboratory animals or cell cultures). However, the reality turns out to be more complex. “It’s an expression that has become a bogeyman. But there is no gain of function here. Certainly, it was modified during its time in the laboratory but it was not modified for the purpose of make it more virulent. On the contrary, it lost 104 elements! The authors also write in their response present in the ‘comments’ part of the article that it has been ‘attenuated'”, continues the researcher. Nothing This also indicates that the so-called “natural” virus could not have infected mice or humans.
“Humanized” mice and results to be nuanced
Let us continue our investigations. The GX_P2V coronavirus was then subjected to four “humanized” mice, in other words genetically modified to present similarities with human cells. They were also kept in an environment favoring their multiplication and therefore the appearance of mutations. The result is clear: 100% of infected mice died. Here again, you have to know how to maintain reason. An infection depends on the characteristics of the host and those of the pathogen. In this experiment, mice were equipped with the human form of the ACE2 receptor, which is the gateway to human cells. If a virus manages to attach itself to this receptor, then it can infect human beings. “However, it should be noted that, if we have the same genetic material throughout our body, a skin cell does not resemble a digestive or heart cell. The problem with these humanized mice is that they express the ACE2 receptor a almost everywhere, and particularly in the brain,” explains Florence Débarre. This certainly explains why the viral load observed by Chinese scientists was particularly high in the brains of rodents. The virus having infected the respiratory system has reached the nervous system. In other words, for the French researcher, “this result is due to the mice used more than to the virus itself”. “When we infect them with Sars-CoV-2, these humanized mice also die!”, she continues.
Beyond the result of this research itself, some question the continuation of the study of dangerous viruses in the laboratory, more than four years after the outbreak of the Covid-19 pandemic. Especially since it is not specified at what biosecurity level these experiments were carried out. “These experiments are dangerous, judges Hervé Fleury, virologist and professor emeritus at the CNRS and the University of Bordeaux. This study carried out in China still shows that we are capable of creating a pangolin coronavirus clone capable of “infect humans, we must therefore supervise them more. In the United States, for example, the House of Representatives has called for the elimination of funds granted to this type of experimentation.” However, this study having the “sole” aim of characterizing an already existing virus, this type of work would not have been prohibited across the Atlantic. For its defenders, on the other hand, it is a necessary evil to work on cures and vaccines even before an epidemic breaks out. Long framed by a moratorium which was lifted in 2017, this practice remains at the discretion of States and research institutes.
There remains one question, highlighted by Bruno Canard, research director at the CNRS and viral replication team leader at the Architecture and Function of Biological Macromolecules (AFMB) laboratory in Marseille, in Le Figaro : “If such manipulations are linked to biological weapons projects, this is particularly worrying.” An assertion brushed aside by Florence Débarre: “If the Chinese army wanted to develop this type of biological weapons, they would have no interest in publishing their work in an American journal.” In any case, Florence Débarre is especially surprised by the response received by this Chinese work: “It is simply fundamental research on viruses. What is new is to see these journeys of disinformation at work.
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