Everything indicates that the Wuhan market was the starting point of Covid-19

Two studies published Tuesday in the prestigious journal Science conclude that the pandemic of Covid-19 started in the market in the city of Wuhan, China, thus pointing to a very probable animal origin of the virus. The first study is a geographical analysis showing that the first cases detected in December 2019 were concentrated around the market. The second study is a genomic analysis of the virus from the first cases, showing that the virus is very unlikely to have circulated widely in humans before November 2019.

The debate makes rage since the start of the pandemic between experts, who are still looking almost three years later to solve the mystery of the origin of the virus.

One of the authors of these studies himself, Michael Worobey, a virologist at the University of Arizona, had signed a letter in 2021 calling for serious consideration of the hypothesis of a leak from a laboratory in Wuhan.

But the data analyzed since made me evolve, to the point that today I also think it is simply not plausible that the virus was introduced in any other way than through the trade in animals at the market of Wuhan “, he said at a press conference.

Kristian Andersen, of the Scripps Research Institute and also a co-author of these studies, said: ” Have we disproved the lab leak theory? No. Can we do it one day? No. But I think it’s important to understand that there are possible scenarios, and probable ones. And that possible doesn’t mean equally likely “.

The spread of the virus starts at the market

The first study analyzed the places of residence of the first 155 cases identified in December 2019. The researchers showed that these cases were concentrated around the Wuhan market, unlike those recorded in the following months, which coincided with high-density neighborhoods. , showing the spread of the virus. Moreover, among the cases studied, people not directly linked to the market lived closer to it than those working there or having recently visited it. This indicates that they were probably infected due to their proximity to this place.

The researchers also analyzed samples taken from the market in January 2020, for example from a cage or carts. Their analyzes show that the samples positive for Sars-Cov-2 were concentrated in the south-west of the market, precisely where live animals were sold (including raccoon dogsa species badgers, foxes, etc.). The animal that would have served asintermediate between the batcarriers of coronavirus, and the human has not been identified.

Better understand to avoid other pandemics

The second study is based on the analysis of the genome of the virus that infected these very first cases. She concludes that two lineages of the virus, A and B existed before February 2020, and that these two lineages probably resulted from two events separated from transmission to humans, both at the Wuhan market. Previous studies had suggested that lineage B had evolved from lineage A.

Going forward, scientists stress that it is important to understand where the animals sold in the Wuhan market came from, in order to minimize future risks. While gray areas therefore remain, the researchers have underlined that the information available on the beginnings of this pandemic were actually very detailed.

” There is this general feeling that there is no information that can tell us anything about the origin of the Covid-19 pandemic.commented Kristian Andersen. It’s just wrong “.

China has regularly been accused of hide information or failing to cooperate fully with international investigations. But understanding how this pandemic started is crucial to help prevent future similar events, and potentially save millions of lives. ” Pandemics don’t require blame, but they do require understanding concluded Kristian Andersen.

Origin of SARS-CoV-2: what does the US intelligence report say?

After the World Health Organization’s report released last March, the United States is making public part of its investigations into the origins of the coronavirus, a question still unanswered.

Article of Julie Kernpublished on September 3, 2021

The burning question of the origin of SARS-CoV-2 is not ready to be elucidated. Two hypotheses are still on the table, without scientists being able to decide between them. On the one hand, that of theemergence nature of a coronavirus almost identical to SARS-CoV-2 during a zoonotic event; on the other, that of the laboratory accident, perhaps linked to the Wuhan Institute of Virology which preserves and studies coronaviruses.

On August 24, Joe Biden, President of the United States, received the conclusions of the report on the investigations into the origins of the coronavirus which he commissioned in May 2021 from theUS intelligence community (IC), a committee that brings together 18 US intelligence agencies. In a shortened form, the findings of this report were declassified on August 27. One thing is certain, tracing the origins of the coronavirus is a stormy undertaking.

Neither biological weapon nor genetically modified virus

” After reviewing all available intelligence reports and other information, the Intelligence community remains divided on the most likely origin of Covid-19. This is perhaps the information to take away from this report. The study of the data available, which are not detailed in the public report, did not make it possible to favor one or the other scenario with certainty. In contrast, IC agencies agree that the coronavirus was not artificially engineered in the lab to serve as a bioweapon, and it was not genetically modified.

The World Health Organization survey (WHO) had judged that the emergence of SARS-CoV-2 following a zoonotic event was the most probable hypothesis and that of a laboratory accident the least probable. The IC considers both hypotheses to be plausible. After investigation, four agencies judge, with a low confidence index, that the zoonosis scenario is the most probable. The coronavirus involved would then have more than 99% similarity with SARS-CoV-2. Another IC agency favors, with a moderate confidence index, the laboratory accident scenario. Someone could have become contaminated when handling an animal or whensampling viruses for example.

So few certainties. Nevertheless, all agree that the lack of epidemiological data, samples from the first patients or collaboration with the Wuhan Institute of Virology complicates the investigations and does not allow a decision to be made in favor of one or the other. another hypothesis. Without the cooperation of China, already requested by the WHO and reiterated by the United States in the conclusion of the report, the research has little chance of advancing.

Origin of the coronavirus: the laboratory accident deemed extremely unlikely by the WHO

Article published on March 30, 2021 by Julie Kern

After their trip to China last February, WHO experts are now sharing their findings in a report. What is the most likely hypothesis regarding the origin of the coronavirus?

Between January and February 2021, twenty-five international scientists affiliates to the World Health Organization (WHO) traveled to China, Hubei province, to investigate the outbreak of the coronavirus.

The report of these experts was published today, March 30, 2021, and details their observations, but above all their conclusions on the four hypotheses explored concerning the origin of the pandemic: the laboratory accident, the infection by food contaminated frozen, the natural transmission of the virus from animals to humans directly from its reservoir or indirectly with the intervention ofan intermediate host.

The hypothesis of the laboratory accident ruled out

The experts studied the probability of each of the hypotheses. The one that is considered the most probable is the hypothesis of the transmission of the virus from animals to humans, the bat still being considered as the reservoir of the virus. If it passed through an intermediate host before infecting humans, it could not be identified by experts.

The possibility that the first people became infected via contaminated frozen food is not excluded but considered less likely. In effect, coronavirus can persist on frozen food or on their packaging. Frozen foodstuffs imported into China have also tested positive, according to WHO experts, suggesting that the coronavirus can survive for a long time under these conditions. Nevertheless, the probability of contamination through this is considered low.

The role of animals, alive or dead, sold in the Wuhan market, remains opaque. Experts were able to determine that the market was indeed a place where the virus spread, but not its source.

Finally, the laboratory accident hypothesis is considered extremely unlikely, after visiting three laboratories in Wuhan, including the Wuhan Institute of Virology. The biosafety rules inherent in the handling of viruses were strictly observed. The virus genome was not detected in the laboratories at the beginning of December, and no employee showed symptoms of Covid-19 at this time.

Hard work still in progress

In a Press releaseTedros Ghrebeyesus, Director General of the WHO said: As far as the WHO is concerned, all the hypotheses remain on the table. This report is a very important start, but it is not the end. We haven’t found the source of the virus yet, and we must continue to follow the science and be on top of things like we do. »

Dr. Peter Ben Embarek, a Danish scientist who participated in this report and presented the results during a virtual press conference, insisted on the difficulty of the work of the experts in the field, in particular to access certain raw data that the China would have been reluctant to share.

This report could not trace the origins of the coronavirus during this trip, other studies will be necessary and will probably require months or even years of investigation. ” Finding the origin of a virus takes time and we owe it to the world to find the source so that we can collectively take action to reduce the risk of it happening again. “, concludes the director general of the WHO.