Evaluating the theory that covid-19 leaked from a Chinese lab –

Evaluating the theory that covid-19 leaked from a Chinese lab – fr

isIT’S POSSIBLE as the chain of infections that spread SARS-COV-2 in the world began, like most new diseases, when an animal virus found itself unsupported in humans, whether in the field or the farm, the cave or the market. It is also possible that the chain started in a Chinese government laboratory. Both of these possibilities have been recognized by many who have studied the covid-19 pandemic for a long time. But just because two things are both possible doesn’t mean they’re equally likely.

During most of the 2020s, scientists and the media tended to view the likelihood of a lab leak as a very small one, with daily contact – a “zoonotic overflow” – extremely likely. This has now changed. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, said in March that the assessment of the laboratory hypothesis had not yet gone deep enough. On May 26, President Joe Biden ordered US intelligence agencies, which have yet to come to a conclusion on the matter, to go away and make more effort.

The artists of the escape

The place most strongly linked to the emergence of SARS-COV-2 is a fish and animal market in the Chinese city of Wuhan. China’s wildlife markets and the trade that supplies them with civets, rats, pangolins and badgers are viral melting pots brimming with opportunities for zoonotic fallout. In the 2010s, a study in Vietnam showed that animals acquire coronaviruses from each other when they go to a restaurant or market; there is no reason to believe that Chinese supply chains are cleaner. In February last year, China announced a ban on consumption and trade in wildlife in recognition of the risks involved. It was an important and costly step.

The first tremors of lab leak concern were caused by simple geography. This market is only 12 km from Wuhan Institute of Virology (WIV), a global coronavirus research center. Wuhan Center for Disease Control and Prevention (CDC), which has also worked on bat coronaviruses, is even closer: just 500 meters. One or more workers at one of these laboratories could have been infected with a coronavirus used in research, thus allowing this virus to pass to the outside world. A related idea is that the virus came directly from a bat or other animal, either inside a lab or as part of fieldwork associated with research. An avid collector of wild bat viruses works for the CDC.

If any of these possibilities turned out to be true, it would be a deep and disturbing irony. Since the beginning of SRAS, a respiratory disease caused by another coronavirus, in the early 2000s, coronaviruses were seen to have a worrying propensity for pandemics. This is what makes them particularly interesting for researchers in Wuhan; their work on coronaviruses was carried out in the name of reducing the threat they posed.

Pathogens escape the institutions that work on them with depressing frequency. The last known death from smallpox was the result of a laboratory leak in Britain in 1978. SARS-COV-1, the virus that causes SRAS, escaped laboratories twice as it spread around the world in 2003, once in Singapore and once in Taiwan; he fled from a Beijing laboratory twice in 2004. In December 2019, more than 100 students and staff from two agricultural research centers in Lanzhou were struck by an outbreak of brucellosis, a bacterial disease commonly caught in the cattle.

Even more alarming, the H1N1 It is now known that the strain of flu that began to spread around the world in 1977 was released from a lab in Northeast Asia – possibly in China, possibly in Russia. Some Western observers suspected it at the time, but made little fuss, perhaps fearing it would lead China and / or Russia to pull out of international influenza surveillance efforts, or trigger an outbreak. reaction against virology.

Biosecurity at WIV was known to be irregular. U.S. diplomats who visited it in 2018 reportedly reported problems, specifically mentioning coronaviruses and the risk of a pandemic. In February 2020, China’s science and technology ministry released new rules forcing labs to improve their biosafety, indicating unease with the status quo.

Charles Darwin, detective

The idea of ​​a lab leak was apparently not unthinkable to those involved. When Shi Zhengli, a coronavirus researcher who is the director of the WIV‘s Center for Emerging Infectious Diseases was interviewed for American scientist in early 2020, she said one of her first concerns was whether the virus could come from her own lab. After looking for recordings of all the viral sequences they had worked with, she concluded that she hadn’t. Yet the Chinese government has seldom hesitated to suppress any information that does not suit it, and Dr Shi may not be able to say otherwise. It is also possible that the virus came from work outside of its competence.

Dr Shi’s group at WIV has spent years trying to understand the mutations that would allow bat viruses to spread in human populations. In pursuit of these questions, they have conducted research aimed at making coronaviruses more infectious to humans. In work published in 2015, they reported a chimera created from a bat coronavirus and a mouse coronavirus capable of replicating efficiently in cells of the human airways.

Some proponents of the lab theory have speculated on what other animals the lab could have used in this work. They point out that the virus looks a lot like a cross between a pangolin virus and a bat virus with additional genetic sequence that makes the virus much more infectious to humans. This “furin cleavage site” is not found in other closely related viruses; maybe it was put there, they say.

There are various counter-arguments to the speculations of these speculations. There’s also a more general caveat based on Charles Darwin’s ideas: natural selection can come up with all kinds of subtleties that sound like overwhelming evidence of smart design to those who start believing in a designer.

What about the evidence for the spread of the disease? According to Guardian, a British newspaper, when the WHO sent scientist Peter Ben Embarek to China in July 2020, his subsequent report to the agency said the Chinese had done “little … in terms of epidemiological investigations around Wuhan since January 2020”. Some conclude that China is not watching because it knows, or perhaps just fears, the answer.

This lack of zeal adds to the suspicion of a laboratory leak. One of the reasons given for the increased interest in such ideas is that only limited additional evidence of zoonotic fallout has come to light; no one has found anything close to a “smoking bat”. When the story of the lab leak seems to have momentum and the story of the zoonosis seems to stick around, it’s natural for people to feel that the lab hypothesis is more and more likely. But this is not strictly logical. It is also important to remember that the relatively rapid progress made on the origin of SRAS in 2003 is not necessarily a reliable guide to how quickly such research normally yields results.

If some data is missing, some is just not being shared. During the WHO At the beginning of this year, Chinese authorities refused requests to provide key epidemiological data on the first 174 known cases of covid-19 in the city in December 2019.

This data is crucial. Not all of the early cases of covid-19 came from the market. Rather than being the source of the outbreak, it could have simply been a place where the virus had spread. This speaks to the need to examine other possible sources, and it requires individualized data on each early case. The absence of such data meant that the WHO the team was unable to conduct a standard epidemiological investigation, Dominic Dwyer, an Australian microbiologist, told the le journal Wall Street at the time. These early cases of covid-19 could clearly point to an animal or laboratory source.

Excitement over the latter possibility was fueled by the re-emergence of claims that three workers in the WIV fell ill with something a little covid in November 2019, according to claims first released by the State Department in the closing days of the Trump administration. But these reports lack corroboration, sources, or details on where those involved actually worked in the lab. This means that they are not doing anything to advance the story.

Evidence to date shows that the circumstantial assumptions upon which the idea is based – that there has been coronavirus research and that it could have leaked – are true; it does not provide a direct snapshot of the epidemic itself. Like Ralph Baric, an American researcher who helped set up the WIVwork on the coronavirus, told the le journal Wall Street, “More investigation and transparency are needed to define the origin”; he himself continues to view zoonotic fallout as the most likely possibility.

Ideally, China would help these investigations uncover new evidence. You can hardly count on that. It’s possible that the hard work of U.S. intelligence services could reveal a compelling case for or against, or that the many scientists studying the details of the virus’s genome and structure may find something. But there is no guarantee that the matter will be resolved soon.

Was it worth it?

For observers such as Filippa Lentzos, a biosafety expert at King’s College London, the uncertainty underscores the need for more discussion of the risks the world is prepared to take in the name of science. More and more pathogen research facilities are being built around the world and even the most sophisticated biosecurity measures can sometimes leak.

This means that research must be conducted in a way that allows for review and accountability, that the knowledge sought must be worth the risks, and that this knowledge, once acquired, must be used and made useful. There is no convincing evidence that the presence of WIV in the city where the covid-19 pandemic began was more than a coincidence. But there is also no evidence that the WIVCoronavirus research, justified in the name of pandemic preparedness, has done everything to reduce the toll of this pandemic.

Dig deeper

All of our pandemic and vaccine related stories can be found on our coronavirus hub. You can also listen to The Jab, our podcast on the race between injections and infections, and find trackers showing the global vaccine rollout, excess deaths by country, and the spread of the virus in Europe and America.

This article appeared in the international section of the print edition under the title “Possible, but far from proven”


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