It’s “extremely unlikely” the COVID-19 pandemic was caused by a virus escaping from the Wuhan Institute of Virology, according to the initial findings of the World Health Organization (WHO) mission to investigate the origin of SARS-CoV-2, the virus that causes COVID-19.
The long-awaited WHO mission is being led by an international team of scientists specializing in virology, zoonotic diseases, and epidemiology. The team arrived in China on January 14 and, after two weeks of quarantine, they embarked on visiting key sites that have been suspected to play a role in the initial stage of the disease outbreak.
Highlighting their preliminary findings at a media conference on Tuesday, February 9, the team notes they have currently found no hard evidence that COVID-19 was spreading within Wuhan before December 2019, when the first cases of the disease were reported. They also say the virus most likely has a natural origin and jumped from a species of animal into humans, although the identity of that animal remains a mystery for now.
The Wuhan Institute of Virology has been accused by some – including top officials of the Trump Administration – of leaking the virus into the surrounding community. The lab was involved in the research of similar coronaviruses, and it's been loosely speculated it was linked to biological weapons research. However, the investigation said this is unlikely, as all signs suggest the virus had a natural origin. They added that the “lab-origin” hypothesis of SARS-CoV-2 is unlikely to be taken seriously in their ongoing studies.
“Our initial findings suggest that the introduction through an intermediary host species is the most likely pathway and one that will require more studies and more specific targeted research,” Dr Peter Ben Embarek, food safety and animal disease expert, said at the press conference (video below).
“However, the findings suggest that the ‘laboratory incidents hypothesis’ is extremely unlikely to explain the introduction of the virus into the human population,” later added Dr Embarek.
Very little is certain so far. While the team indicates the virus has a zoonotic origin, meaning it’s a virus that has jumped from another species of animal to humans, the identity of this animal still remains unclear.
The WHO team notes that extremely similar coronaviruses have been detected in wild bats in China and other parts of East Asia. However, the city of Wuhan is not close to these wild bat populations, suggesting another animal acted as an intermediary. The Huanan Seafood Market was long-suspected to play a central role in the emergence of the disease, as many of the early cases in December 2019 were linked to the site. Equally, the close contact of animals and humans would make it the prime location for a zoonotic leap from animals to humans. However, other early COVID-19 cases in Wuhan have no connection to the market, raising doubts that it's the original setting of the outbreak.
"How it was introduced and spread within the [Huanan Seafood] market is still unknown," Dr Embarek explained.
There's a chance this zoonotic jump into the human population came from a wild animal or an animal that was part of the food supply chain, they suggest. The team adds they are especially interested in investigating the role of frozen food in the emergence of the virus.
“We are still working with the hypothesis that it could have been introduced by a person who was infected and then spread to other persons in the market. But it could also be through the introduction of a product. Among the more interesting products were frozen farmed wild animals. Some of these species are known to be susceptible to these kinds of viruses,” added Embarek.