French researchers from the Pasteur Institute published in the scientific journal Nature on February 16 a study in which they studied 645 bats living in caves in Laos. They ended up discovering three types of coronavirus very close to the one we’ve been familiar with for two years, including one of the most analyzed ever.
In addition, the viruses analyzed are as infectious to humans as SARS-CoV-2. This is the first time such a characteristic has been observed on bat coronaviruses in Asia.
These three viruses have a domain called RBD (receptor-binding domain), located on the spike protein, which allows it to bind to human cells. Of the 17 functionally important amino acids in this domain, only one or two differ from those of SARS-CoV-2. Scientists have demonstrated their ability to enter human cells and reproduce.
However, the study showed the absence of virin cleavage, which allows Covid-19 to enter human respiratory cells and cause the virus to be highly contagious. Mark Elwett, who led the study, told L’Express that other “close” viruses could pose a risk to human health.
If this thesis makes it possible to advance knowledge about the origin of Covid-19, it does not explain how the virus managed to emerge in Wuhan, China, while the bats studied come from southern China, northern Laos and Vietnam.
Hypotheses claim that Covid-19 could have spread covertly between humans before mutating and gaining the ability to contaminate or that it would be the first known coronavirus to have acquired this characteristic. This would have allowed him to pass more easily from animals to humans. As for the famous pangolin chosen at the beginning of the epidemic, it will only be a side victim, infected by bats. According to the virologist behind the study, it would only be an intermediary between bats and humans. “The pangolin would have appeared as a crucible, because in this animal we found coronaviruses with RBD closest to SARS-CoV-2. With the viruses found, the pangolin no longer appears as a potential mediator. But most likely a side victim infected with bats. »
It does not appear that China is ready yet to conduct an investigation on its territory. In May 2021, the US President requested a 90-day report on the origins of the coronavirus pandemic. In March 2021, the first investigation by Beijing and the World Health Organization confirmed that a coronavirus found in bats and transmitted to humans via an intermediate animal was the “most likely scenario”. As for the hypothesis of a virus escaping from the laboratory, this was considered “unlikely”.
In August 2021, China vetoed a new WHO investigation into its territory. It considered that the conclusions reached during the first investigations conducted by the World Health Organization were sufficient and that there was no need for further research. Moreover, for Ma Gaoxu, Vice Foreign Minister, this approach was above all political.
