origin of Covid-19, investigation impossible?

Five years after the first death from Covid-19, on January 11, 2020, the WHO asked China to release data concerning the origin of Sars-CoV-2. The virus at the origin of the biggest pandemic of the century but its origin is still subject to different versions explained by the difficulty in determining with certainty where and when the virus was born.

“With all the data we currently have, the evidence points towards a natural origin of the virus”explains Florence Débarre, research director in evolutionary biology at the CNRS. According to her, the virus was transmitted to humans by a wild animal such as the raccoon dog or the civet, which we know were present at the Wuhan fish market.

The natural origin of the virus remains the most credible

A thesis which is all the more credible since many of the first human cases identified “either worked at the market, or were linked to the market or lived near this market. The two original lineages of the virus have also been identified in this market”explains the scientist. In September, she and her group of researchers discovered the presence of raccoon dogs and civet cats on the market, the animals that caused SARS 15 years earlier. A striking coincidence in a city as large as Île-de-France. “But these animals were no longer present at 1^is January 2020, when the first samples were taken”.

But this thesis is not the only credible one, says Antoine Flahault, epidemiologist at the University of Geneva. “We cannot completely rule out the origin of an accidental leak from a laboratory”. He opts for the third option. “ Rhinolophus bats have been found in Wuhan. I think the virus may have started during the flying mammal capture campaigns in Laos. “, he explains.

According to him, a researcher or technician could have been bitten by one of these specimens and become a carrier of Sars-CoV-2. “It is enough that this person is young, in good health and does not necessarily present symptoms – as is sometimes the case with Covid-19 – and after several weeks the disease can be transmitted”he says.

No search for the culprit

According to him, this hypothesis deserves to be explored further and the WHO could ask the laboratory teams working on coronaviruses if such capture campaigns took place in the 18 months preceding the pandemic.

If this hypothesis is credible, it is not the most shared by the scientific community, which sees “mostly” an animal origin and transmission from the market, recalls Florence Débarre. Except in China, where this track “is not the preferred hypothesis” Currently.

The problem is that none of the hypotheses can be definitively ruled out. It is certainly to try to clarify this mystery a little further that the WHO requested new data from China on December 30, 2024. “It will be difficult to have a definitive answer. The main obstacle in this quest is that research into the origin of Sars-CoV-2 is seen by some as a search for a culprit. What can slow down data sharing »says Florence Débarre.

However, the origin of Covid-19, even if it remains uncertain, is (on the contrary) one of the best documented in history, recalls the researchers. “For example, there is much less data on the origin of SARS, but the hypothesis of its natural origin is not called into question”details Florence Débarre. Same thing for the H1N1 flu for example. “Ultimately, determining the exact origin of an infectious disease such as Covid-19 is not the most decisive thing”agrees Antoine Flahault.

Know the origins to avoid repeating the same mistakes

However, this search for origins can be a determining factor for the future, whatever the results of this investigation. What matters is how we react in retrospect to prevent the spread of new viruses like this.

“Lessons must be learned. This is why the more credible a hypothesis is, the more we will be able to anticipate.explains Antoine Flahault. “We already know that the importation of wild animals like those present at the Wuhan market into urban centers are very risky practices”continues Florence Débarre. This could intensify controls.

Likewise in the event of a leak from a laboratory or poor practice when capturing bats. “We could impose a preventive quarantine on capture teams, for example. If the leak comes from the laboratory, protocols would have to be modified in structures all over the world”lists Antoine Flahault.

This is why the scientist is campaigning for greater power for UN agencies, in particular the WHO. “We should be able to have control, particularly over laboratories, like what is done at the nuclear level”. What the WHO treaty aims towards. “But the states are putting on the brakes. » Further complicating this quest for truth that inhabits researchers.