WHO investigators say COVID-19 virus unlikely to have leaked from Chinese lab

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More than a year after COVID-19 began to spread across the world and nearly a month after a team of investigators arrived in Wuhan to study its origins, the World Health Organization says it has no answers as to where the pandemic began – but it nonetheless strongly discounts the possibility the virus came from a lab.

It’s now time, the organization said, to expand the search beyond China – perhaps to neighbouring countries whose exports of frozen animals were sold at markets in Wuhan.

“Our focus needs to shift to those supply chains to the market, supply chains from outside China,” said Peter Daszak, a parasitologist and ecologist on the WHO experts team. The group has been in Wuhan since Jan. 14 and on Tuesday discussed its efforts – and lack of substantive findings – in tracing the origins of the pandemic. Future efforts must look more closely at “Southeast Asia, on where the origins of this viral clade that led to SARS-CoV-2 might be,” Mr. Daszak said.

It was the clearest indication that the world’s pre-eminent international health body is throwing its weight behind a series of theories popularized in China – most notably the possibility that the virus that first broke out in Wuhan may not have originated in the city at all, but may have arrived on chilled food.

Despite uncovering no evidence of natural transmission of the virus from animals, the WHO dismissed as “extremely unlikely” the possibility that the virus arose from work in a Wuhan laboratory whose research included taking bat viruses and manipulating them to make them more transmissible to humans through gain-of-function research.

Important questions remain about the thoroughness of China’s search for the roots of a global epidemic that has now killed more than 2.3 million globally. Though Wuhan stood as ground zero for the pandemic, Chinese authorities have not rigorously tested previously collected blood samples to look for signs of the virus before a Dec. 8, 2019, case officially designated as the first in the city.

Such studies have been done in other countries, and a blood donor centre in Wuhan has “samples available,” said Thea Fischer, a member of the WHO team. But what’s important is that any testing is done in a way that is not merely “convenient,” she said.

“If it’s only based on children, you don’t really get much information if you’re looking for early cases of SARS-CoV-2,” she said. She has recommended a proper study. “One of the evidence-based investigations that would bring us closer to a potential circulation in the population earlier on would be a seroprevalence study that is conducted on a systematic collection,” she said.

But other officials from China and the WHO declared Tuesday that their searches had yielded no sign of the virus in Wuhan before Dec. 8, nor any definitive indication of the path it took from microscopic matter to global killer.

A total of 4,500 stool samples from Wuhan and other cities in Hubei province gave no evidence of SARS-CoV-2 before December, 2019. Sales of fever medication showed no early spike, nor did analysis of urban death rates.

“In terms of understanding what happened in the early days in December, 2019, did we change dramatically the picture we had beforehand? I don’t think so,” said Peter Ben Embarek, head of the WHO mission.

“We did not find evidence of large outbreaks that could be related to cases of COVID-19 prior to December, 2019, in Wuhan or elsewhere.”

In animals, too, the WHO – which relied primarily on work by Chinese researchers – said it had come up empty. COVID-19 may have leapt from animals to humans, “but the reservoir hosts remain to be identified,” said Liang Wannian, head of the expert group on the novel coronavirus outbreak response and disposal at China’s National Health Commission.

Tests of 11,000 livestock and poultry taken from 31 different provinces and regions yielded no positive results. Nearly 2,000 serological antibody tests of 35 wild animal species showed no indication of the virus, either before or after the Wuhan outbreak. A further 50,000 COVID-19 tests from 300 species of wild animals revealed nothing. “It doesn’t look like there was wide circulation of the virus in any animal species in the country,” Dr. Ben Embarek said.

The WHO scientists suggested closer scrutiny of different animal species that could have been intermediaries. Minks and cats could “act as a potential reservoir,” Dr. Liang said. Rabbits, ferret-badgers or bamboo rats also merit further study, said Marion Koopmans, a Dutch virologist also on the WHO team.

But any future tracing work will “not be bound to any location and may evolve geographically,” Dr. Liang said, suggesting a move to take the search for the virus origins beyond China’s borders. The WHO is planning a news conference on Friday to discuss where it plans to go next.

The WHO said it no longer intends to ask questions about what took place inside laboratories such as the Wuhan Institute of Virology, which holds a repository of bat coronaviruses. That theory is not worthy of future study, Dr. Ben Embarek said. With the Institute of Virology, for instance, the WHO team looked at the “state of that laboratory and it was very unlikely that anything could escape from such a place,” he said.

But the Wuhan Institute of Virology had collected at least one bat virus with a 96-per-cent genetic similarity to SARS-CoV-2. The lab also conducted gain-of-function work designed to enhance the human infectiousness of bat viruses, a controversial line of research whose advocates say is a tool for pandemic preparedness.

Asked if the WHO had examined the Wuhan records of such work, Dr. Ben Embarek said the institute’s staff “gave us a very detailed description of their research, both present and past.”

The WHO, which has since the earliest days of the pandemic been criticized for being too cozy with China, then offered the Wuhan virus scientists some advice on how to parry skeptics.

“We discussed how to improve that communication, how to provide the right arguments in the future for better explaining their position,” Dr. Ben Embarek said, adding the WHO believes that by “taking our detailed and rational approach, we will help better clarify some of these claims around specific studies, gain-of-function, working with samples directly from bats etc.”

In a press briefing on Tuesday, White House press secretary Jen Psaki said the Biden administration is looking forward to scrutinizing data included in the WHO report.

Ms. Psaki told reporters that the administration was not involved in the “planning and implementation” of the investigation and wants to take an independent review of its findings and underlying data.

She added that even though the U.S. administration recently rejoined the World Health Organization, it is “imperative that we have our own team of experts on the ground.”

With a report from Reuters

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