Lab leak or animal transmission? After three and a half years of research, the conclusion remains the same: the origin of Covid remains a mystery, according to the WHO, which continues to deplore the lack of information provided by Beijing.
"All hypotheses must remain on the table, including zoonotic spread and laboratory leaks," World Health Organization chief Tedros Adhanom Ghebreyesus said Friday after presenting the findings of a report by experts examining the origin of Covid.
"The WHO acknowledges that China has shared some (...) information, but not all of that requested," he said.
The Covid-19 pandemic has killed millions – 20 million according to the WHO – and devastated the global economy.
The first known cases of the disease occurred in late 2019 in Wuhan, China, which houses a virology institute renowned for its research on coronaviruses.
For many experts, understanding the origins of Covid is important if the world is to be able to implement effective countermeasures in the future and avoid new pandemics.
The lengthy investigation conducted by the WHO's Scientific Advisory Group on the Origins of Novel Pathogens (SAGO) has not provided any clearer insight into the origin of Covid: "nothing has been concluded with absolute certainty," acknowledged Maria Van Kerkhove, the American epidemiologist who heads the WHO's Department of Epidemic and Pandemic Prevention and Preparedness.
– Wuhan –
Whether Covid-19 accidentally escaped from a laboratory or spread from an animal to humans remains debated.
A large part of the scientific community nevertheless leans towards the theory of transmission to humans via an intermediary animal, probably infected by a bat.
But the lab leak theory, once considered a conspiracy theory, has recently gained popularity in the United States. American agencies such as the FBI and the Department of Energy now support it with varying degrees of certainty.
And the White House unveiled a revamped version of its Covid-19 website in April promoting this theory, presented as the "true origin" of the virus.
The CIA, the United States' main intelligence agency, also estimated in January "with a low degree of confidence (...) that a research-related origin of the Covid-19 pandemic is more likely than a natural origin."
A hypothesis that China had deemed "extremely improbable."
In 2021, a month-long mission of WHO-commissioned experts to China appeared to rule out the possibility that the virus could have escaped from the Wuhan virology institute.
But the mission was only able to visit China a little over a year after the start of an epidemic, with Beijing seeming very reluctant to let them come.
His conclusions were greeted with caution, if not skepticism, particularly in the United States. The head of the WHO quickly reframed the discussion by stating that "all hypotheses remain on the table."
– Lack of information –
This time again, he lamented the lack of data received.
The WHO has asked China "to share hundreds of genetic sequences from people who had Covid-19 early in the pandemic, more detailed information on animals sold in Wuhan markets, and information on the work carried out and biosafety conditions in Wuhan laboratories."
But "to date, China has not shared this information with either SAGO or the WHO," the organization said in a statement.
Much of the information needed to assess the laboratory leak hypothesis was not shared with experts, "despite repeated requests to the Chinese government, so this hypothesis could not be studied or excluded," SAGO president Marietjie Venter told reporters.
The experts also requested information on this from other countries, "particularly Germany and the United States," but again, nothing has been forthcoming, she said.
English 
French