Health & Fitness

WHO says Covid "most probably" originated from animals and can unfold to people, and rejects laboratory leak idea

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Peter Ben Embarek and Marion Koopmans (R) come to a press conference on February 9, 2021 to conclude a visit by an international team of experts from the World Health Organization (WHO) to the city of Wuhan in the Chinese province of Hefei.

HECTOR RETAMAL | AFP | Getty Images

An international team of scientists led by the World Health Organization said Tuesday that the coronavirus "most likely" came from animals before it spreads to humans, rejecting the theory that the disease leaked from a laboratory in the Chinese city of Wuhan.

Scientists have been working in Wuhan, where the disease was identified, for four weeks, looking for clues about the causes of the Covid-19 pandemic.

Investigators have visited hospitals, laboratories and markets, including the Huanan Seafood Market, the Wuhan Institute of Virology and the Wuhan Center for Disease Control laboratory.

During the secret visit, researchers were also supposed to speak to early responders and some of the early patients. The team completed two weeks of quarantine before starting visiting local locations.

Dr. Peter Ben Embarek, WHO food safety and animal diseases specialist and chair of the investigation team, told reporters the "most likely" path for Covid is to transition from an intermediate species to humans. That hypothesis will "require more study and more specific (and) targeted research," he said.

The first results of the investigation found no evidence of major Covid outbreaks in Wuhan or anywhere else before December 2019. However, researchers found evidence of greater Covid spread outside of the Huanan seafood market this month, Ben Embarek said.

He added that it was not yet possible to determine the intermediate animal host for the coronavirus and described the results as "in the works" after nearly a month of meetings and site visits.

"To understand what happened in the early days of December 2019, we dramatically changed the image we had before? I don't think so," said Ben Embarek.

"Have we improved our understanding? Have we added details to this story? Absolutely," he said.

WHO has tried to meet expectations for a definitive conclusion on the origins of the Covid pandemic. To put the mission in a broader context, it took more than a decade to find the origins of SARS, while the origins of Ebola – first identified in the 1970s – are not yet known.

It is hoped that information on the earliest known cases of the coronavirus, first discovered in Wuhan in late 2019, can help pinpoint the start of the outbreak and prevent future pandemics.

Laboratory leak "extremely unlikely"

A theory that the coronavirus leaked from the Wuhan Institute of Virology has been discredited by WHO investigators. The hypothesis had been upheld by the administration of former President Donald Trump without any burden of proof and was strictly denied by Chinese officials.

"It is extremely unlikely that a laboratory incident hypothesis could explain the introduction of the virus into the human population," said Ben Embarek. "Hence (it) is not in the hypotheses that we will propose for future studies."

The team had concluded that a laboratory leak should be considered extremely unlikely "based on serious discussion and very careful research," added Liang Wannian, head of Covid's expert panel at China's National Health Commission.

Mink are seen on a farm in Gjol, Northern Denmark on October 9, 2020.

HENNING BAGGER | Ritzau Scanpix | AFP via Getty Images

Speaking to Ben Embarek of the Hilton Optics Valley Hotel in Wuhan, Liang said ongoing research into the origins of the virus needs to focus on how it circulates in animals before humans are infected.

Bats and pangolins are potential candidates for transmission, Liang said, but samples from these species are not "sufficiently similar" to the coronavirus.

The high susceptibility of minks and cats to the virus suggests that there may be other animals that act as reservoirs, Liang continued, but the research remains inconclusive.

China's National Health Commission spokesman said there might have been an unreported spread of the coronavirus before it was discovered in Wuhan. However, Liang said there was no evidence of significant spread of Covid in Wuhan prior to the outbreak in late 2019.

International concern

The WHO previously cited genetic sequencing that showed the coronavirus had started in bats and likely jumped to another animal before infecting the human.

Many of the people who contracted the new virus in Wuhan, a city of around 11 million people, are said to have had connections with the Huanan Seafood Market.

Scientists initially suspected the virus came from wildlife sold in the fish market, which prompted China to swiftly restrict public access to the market early last year.

China's CDC has since said samples from the fish market suggest that the virus has spread from where the outbreak first occurred.

On Tuesday, Liang said the Huanan fish market was one of the places where the coronavirus first appeared, but he added that current evidence is unable to determine how the virus was introduced into the fish market.

Security guards stand guard outside the Wuhan Institute of Virology in Wuhan as members of the World Health Organization (WHO) team investigating the origins of the COVID-19 coronavirus visit the institute in Wuhan, Central China's Hubei Province, on February 3, 2021.

HECTOR RETAMAL | AFP | Getty Images

The origins of the coronavirus remain important as the virus is constantly evolving, as demonstrated by highly infectious mutant strains in the UK and South Africa.

According to data from Johns Hopkins University, more than 106 million people worldwide have contracted the coronavirus and killed at least 2.32 million people.

The US has by far reported the highest number of confirmed Covid cases and deaths, with more than 27 million reported infections and 465,072 deaths.

China has released little information about its research into the origins of the virus, and there has been widespread international concern about what researchers in Wuhan are allowed to see and do as part of their research.

– CNBC's Evelyn Cheng contributed to this report.

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Katherine Clark