WHO investigation into origin of COVID-19 says laboratory incident “extremely unlikely”

Peter Ben Embarek displays a diagram of the pathways to emergence during the WHO press conference in Wuhan, China on February 9, 2021.

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A group of expert investigators convened by the World Health Organization and China to examine the murky and complex origins of the coronavirus pandemic revealed the first findings of a fact-finding mission that began just under two weeks ago. Liang Wannian, one of the scientists with the Chinese National Health Commission, told reporters at a press conference on Tuesday that the team had not found clear evidence of an animal overflow at the man.

“We came here with two goals,” said Peter Ben Embarek, a WHO expert in food safety and zoonosis (disease transmitted from animals to humans), “One was to try to better understand what s ‘happened at the start of the event in December 2019. At the same time, we also embarked on an attempt to understand … how the virus came about. “

Two hypotheses have arisen since the start of the pandemic. A majority of scientists believe SARS-CoV-2, the virus that causes COVID-19, originated in bats and jumped into humans, potentially via an intermediate species. Another theory, which has gained momentum in recent months, is the idea that a bat coronavirus may have been brought back to a Wuhan lab and then accidentally escaped.

The WHO team of 14 scientists and researchers emerged from quarantine of hotels in Wuhan on January 28 and spent 12 days visiting sites in Wuhan, including the Huanan Seafood Market, where many cases were discovered, and the Wuhan Institute of Virology, which has been known to research bat coronaviruses and has been hypothetical as the site of an accidental laboratory leak.

Liang, team leader Ben Embarek and Marion Koopmans, virologist at Erasmus University Medical Center in the Netherlands, presented the results and answered journalists’ questions. They evaluated four hypotheses: a direct passage from animals to humans, introduction to humans via an intermediate host, the virus arriving in Wuhan via frozen food products and a laboratory-related incident.

See also: How many COVID-19 vaccinations in your state? How to follow it

The conference was light on the data, but on the four hypotheses, the team concluded that a laboratory origin is “extremely unlikely.” A jump from a bat via an intermediate species would be most likely.

“For me, the most important conclusion is that the virus is of natural origin,” said Roger Frutos, molecular microbiologist at the French Center for Agricultural Research for International Development, or Cirad, not affiliated with the survey. “It closes the door on accident or engineering theories.”

Other conclusions, revealed by the panel:

On the first cases and the Huanan seafood market

  • “The results indicated that there is no substantial unrecognized circulation of SARS-CoV-2 in Wuhan during the latter part of 2019,” Liang said.
  • It is not possible to determine how SARS-CoV-2 was first introduced to the Huanan market.
  • “The date of occurrence of the first case in this research was December 8,” Liang said. This conflicts with data published in the journal The Lancet, which suggests that the first case dates from December 1.
  • Liang also suggested that circulation to areas outside of China may have occurred before December 2019, when the virus was first detected in Wuhan. This theory and the publications surrounding it are considered to be erroneous. “We have not found any evidence of significant outbreaks that could be linked to COVID-19 before December 19 in Wuhan or elsewhere,” noted Ben Embarek.
  • “A direct bat jump in Wuhan city is not very likely,” Ben Embarek said.

On the origins

  • “Our early results suggest that introduction via an intermediate host species is the most likely route and will require more studies and more specific targeted research,” said Ben Embarek.
  • “The hypothesis of a direct overflow from an animal source of origin is also a possible avenue and also generates recommendations for future studies,” he said.
  • “The results suggest that the hypothesis of a laboratory incident is extremely unlikely to explain the introduction of the virus into the human population,” he said.

About the lab leak

  • “We have examined what are the arguments for and against [the lab hypothesis]”Ben Embarek said.” We are looking into the fact that nowhere before has this particular virus been researched, identified or known. “
  • “We were also discussing with officials and staff of many relevant laboratories in the region and reviewing and discussing this hypothesis with them,” he said.
  • “We also looked at the Wuhan Institute of Virology and the condition of that lab… and it was very unlikely that anything could escape from such a place,” he noted.

On the sampling of other animal species

  • “Sampling of bats in Hubei province has not found evidence of SARS-CoV-2 in native viruses, and sampling of wildlife in different locations in China has so far failed. ‘now not able to identify the presence of SARS-CoV-2,’ Liang said.
  • 11,000 samples of different types of animals like “pig, cow, goat, chicken, duck and goose” from 31 provinces of China in 2019 and 2020 and all were negative for SARS-CoV-2.
  • 1,914 serum samples from 45 different species of wildlife, collected between November 2019 and March 2020, were all negative for SARS-CoV-2.
  • 50,000 samples of wild animals covering 300 different species were tested by PCR and all tested negative for SARS-CoV-2.

China only agreed to an origins inquiry after international pressure at the World Health Assembly in May 2020. Australia called for an independent origins inquiry, straining relations between nations. Some scientists have suggested that although the investigative team has the expertise to trace natural origins, they may not have the expertise to investigate a possible laboratory origin.

The press conference, which lasted just under three hours, did not provide much news and no data, but a full report is being prepared. We don’t know when that will be ready. Ben Embarek made it clear that the team had “been able to develop a set of recommendations for future studies.” He said there is material, such as blood from blood banks, that could give the team a better picture of the early days of the pandemic.

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