Laboratory leak, guilt of the pangolin, the bat, local market, frozen food… Five years after the appearance of Covid-19, the international scientific community has not been able to determine with certainty its origin.
On January 11, 2020, the world learned of the death of the first official victim of atypical pneumonia, later identified as Covid-19. The 61-year-old man frequented the Wuhan animal market. Ten days later, the city and its province, then a large part of the world, were confined.
Predominant hypotheses
“To summarize, we can say that to date two major hypotheses predominate in the scientific debate, enlightens epidemiologist Antoine Flahault. The first concerns the Wuhan market, which appears to be the epicenter of the start of the pandemic. The second is that of aWuhan laboratory leak in which researchers work on coronaviruses. I would personally favor a third hypothesis: contamination during a coronavirus collection in caves on the border of China and Laos. We know that laboratory technicians went there and came back with samples, one could have been bitten by a bat and developed completely benign Covid, which would then have been transmitted to the population of Wuhan. »
In recent months, published reports and studies have leaned towards one possibility or the other. On December 3, a report from a US Congressional committee estimated that the laboratory leak was the preferred scenario and that it could not be relegated to a conspiracy theory. In September, a study published in the journal Cell reinforced the hypothesis of transmission to humans by animals infected at the end of 2019 in the Wuhan market.
“In March 2023, we found genetic data corresponding to samples taken at the Wuhan market at the beginning of 2020. They indicated that animals such as raccoon dogs or civets (already involved during the first SARS episode in 2002-2004 ) were present on the market in an area where many samples contained traces of Sars-CoV-2”explains Florence Débarre, co-author of the study and researcher at the CNRS.
Learn lessons
Despite these advances, nothing will ever make it possible to state with certainty the origin of Covid-19. “The data we worked on is consistent with the Wuhan market hypothesis, but it does not provide definitive proof”recognizes Florence Débarre. If the researcher leans towards this theory, “some will always doubt”. And this, even if the Chinese authorities cooperated more.
“It is difficult to move forward on the subject because some have made the search for the origin into the search for a culprit, which does not facilitate cooperation. To know for sure, you would need a time machine. But a lot of data is already available, and points in the direction of a natural origin,” continues the researcher.
For Antoine Flahault, «this is also part of the scientific mystery, in the same way that we still do not know how they mutated Covid variants, like Omicron. This does not prevent us from learning lessons from the pandemic. The hypotheses, which are all probable, are enough to take precautionary measures. »
