Health

WHO team’s quest to trace COVID-19’s origins in China draws a blank

It, however, concluded that SARS-CoV-2 could not have leaked from a research lab

 
By Vibha Varshney
Published: Tuesday 09 February 2021
Photo: Peter Daszak / Twitter
Photo: Peter Daszak / Twitter Photo: Peter Daszak / Twitter

The team deployed to trace the source of SARS-CoV-2 in China was unable to do so. But it conclusively ruled out the possibility that the virus could have escaped from a research lab in Wuhan in Hubei province.

“No lab was working on this or a similar virus,” Peter Ben Embarek from the World Health Organization (WHO), who was part of the team, said at a press meeting in China on February 9, 2021.

“The labs maintain high standards and the lab leak hypothesis is very unlikely,” Liang Wannian, head of the expert panel on novel coronavirus disease (COVID-19) response at China’s National Health Commission, added.

The WHO-convened Global Study of Origins of SARS-CoV-2 research team began the study on January 14 to understand the events at the beginning of the epidemic — how it happened and how the disease transferred to humans. While these are the results from China, similar studies would be carried out in other parts of the world too.

The team found no conclusive evidence to indicate that there were cases of the disease in the country before December 2019 in Wuhan or in other parts of the country. This puts to rest the theory that China knew about the outbreak much in advance and suppressed the facts.

The team tried to find if the spread of the disease could be linked to the direct zoonotic spillover into the human population or enter through an intermediary host that are closer to humans.

Other than this, they also looked at the role of frozen food acting as surface for transmission and the possibility of a laboratory-related incidence that could have released the virus in the environment.

The researchers were unable to identify the wild reservoir of the virus. While bats are the natural reservoirs of the virus, these were not present in Wuhan and the team suggests that an intermediate host theory is more plausible.

The Huanan Sea Food Market in Wuhan, that was in the spotlight at the beginning, dealt with domesticated wildlife that could have been the source. Frozen food from different parts of China and even from outside the country was sold in the market. The joint team has identified the traders and vendors and farms from where the products were coming from and will work further in this direction.

Wannian pointed out that these were the first findings of the major global study and the results from China will set ground for work in other parts of the world.

While the disease spread to people who visited the market, it was also evident in people who had not come to the market. It could have been introduced through an infected person who could be one of the traders or buyers. It could be through products such as farmed wildlife animals. All this is providing clues for the direction of future studies.

Marion Koopmans, head of the Erasmus MC department of Viroscience in the Netherlands, who was part of the team said figuring out the exact role of each of these in the spread of the disease was complex and only broad categories could be established. With new information, new understanding would emerge, she added.

The findings would help researchers prioritise future research in identifying the source of the disease. While the WHO-convened team suggested that researchers continue to look at the first three sources, they said the lab incidence hypothesis was extremely unlikely and there was no need to carry out future studies in this direction.

No evidence for the patient zero emerged from the studies. The pandemic first emerged in China’s Wuhan by the end of 2019. As of February 9, 2021, 106,008,943 confirmed cases of COVID-19, including 2,316,389 deaths have been reported globally.

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