THE ESSENTIAL
- Two years following the start of the Covid-19 pandemic, the origin of the virus responsible for the disease remains unclear
- Work carried out by the Institut Pasteur favors an animal origin of SARS-CoV-2 which would have come from bats
- Pasteur’s scientists dismiss the laboratory accident thesis
The bat is making a comeback in the Covid-19 news. From waves to successive variants, the subject of the origin of the virus responsible for the pandemic had almost become secondary. But French researchers from the Institut Pasteur, two years following the start of the health crisis, are now reviving the trail of… the bat. Exit the pangolin, designated culprit during the first weeks of the epidemic, exit also the laboratory accident, a hypothesis yet documented beyond the highly contested assertions of Professor Luc Montagnier, former Nobel Prize in Medicine recently deceased.
Two years of crisis and nearly 6 million deaths
Two years of upheavals in daily life around the world and a human toll that amounts to nearly 6 million deaths mean that the question of the origin of the virus deserves some answers. In August 2021, a report by US intelligence agencies left all avenues open: animal origin or laboratory accident were considered equally with however an agreement on the fact that the virus would not have been “tampered with” or genetically modified in the laboratory and even less designed to be a bacteriological weapon.
Similarities that plead for a common origin
This time, researchers from the Institut Pasteur whose work has been published in the journal Nature advance the high probability of an animal origin of SARS-CoV-2. They identified three viruses detected in bats living between southern China and Vietnam whose genetic sequences are very close to that of SARS-CoV-2. These viruses are able to infect humans through the link between their Spike protein and the ACE2 receptor of human cells and, in addition, the antibodies produced once morest SARS-CoV-2 are able to block them. So many similarities that argue for a common origin between these viruses and the one responsible for the Covid-19 epidemic.
A peculiarity of SARS-CoV-2
The only difference, but it is important, between the viruses studied and SARS-CoV-2, the absence of what is called the furin cleavage site, a group of amino acids that promotes the cell penetration from the Spike protein and which causes the strong contagiousness of the Covid-19 virus. According to Pasteur’s researchers, several explanations for this particularity of SARS-CoV-2 are possible: either its silent circulation in humans which would have allowed it to mutate and acquire this faculty of contamination, or it would be the first known coronavirus. to have this characteristic which would have allowed him to pass more easily from animal to human.
Can these works by scientists from the Institut Pasteur, who a priori dismiss the laboratory accident thesis, close the debate on the origins of SARS-CoV-2? The end of the story is probably not yet written: on the one hand, other scientists are also working on this question and, above all, the work carried out on SARS-CoV-2 itself and its variants can at any time bring revelations regarding its nature and its still partially unknown effects. And, thus, why not, to open other tracks.
