Interesting article on the WHO investigation, from the WSJ
WUHAN, ChinaâThe virus that causes Covid-19 most likely jumped from one species to another before entering the human population and is highly unlikely to have leaked from a laboratory, a leader of a World Health Organization investigative team said at a press conference here.
In laying out the possibilities for the origin of the pandemic, the WHO team on Tuesday said it was also possible that the virus may have been transmitted to humans through imported frozen food, a theory heavily promoted by Beijing. But the team said the most likely scenario was one in which the virus spilled over naturally from an animal into humans, such as from a bat to a small mammal that then infected a person.
âDid we change dramatically the picture we had beforehand? I donât think so,â said Peter Ben Embarek, a Danish food-safety expert who spoke on behalf of the WHO delegation. âDid we improve our understanding? Did we add details to that picture? Absolutely.â
The preliminary assessment came during a press conference at the end of a four-week mission, which included two weeks of quarantine, to Wuhan, the original center of the pandemic. It comes more than a year after the virus first began spreading in China and around the globe, killing more than two million people.
After reviewing environmental samples from Wuhanâs Huanan Market, as well as thousands of biological samples and case files from more than 200 local hospitals, 17 Chinese and 17 WHO experts said the market was one place where the virus began spreading rapidly, but cautioned that it was impossible to say how the virus arrived there.
Several smaller outbreaks followed by early clusters in the market would have adhered to a âclassical picture of an emerging outbreak,â Dr. Ben Embarek said. However, he didnât rule out the possibility that the first outbreak could have occurred outside Wuhan, including in another Chinese province or in another country.
âThe market probably was a setting where that kind of spread could have happened easily, but that is not the whole story,â Dr. Ben Embarek said.
Another member of the WHO team, Peter Daszak, went further, telling reporters after the press conference that the focus of the investigation was shifting toward countriesâespecially in Southeast Asiaâthat could have been the source of animals or animal products sold in Wuhanâs Huanan Market.
âWeâve done a lot of work in China and if you map that back, it starts to point towards the border and we know there is very little surveillance on the other side in the whole region of Southeast Asia,â he said. âI think our focus needs to shift to those supply chains to the market, supply chains from outside China, even.â
The preliminary findings arenât likely to calm the political controversy around the investigation into the origins of the pandemic. Both Beijing and Washington traded blame throughout much of 2020 for the early spread of the virus, and the WHO visit was arranged only after lengthy negotiations with the Chinese government.
Many virologists outside China believe the first outbreak began within Chinese borders and are skeptical of the idea that imported frozen food ignited a global pandemic.
The WHO risks validating Chinese government claims that many scientists consider a far-fetched theory, said Lawrence Gostin, a professor of global health law at Georgetown University.
âI would not give credence at this stage to Chinaâs story line about what it wants to project to the world. WHO has been on that path before and it should not get on that path again,â he said. âOne has to point out that this has taken place over a year laterâ¦Itâs like going to the scene of a crime a year later, when itâs been scrubbed. Itâs very hard to solve it.â
WHO researchers, including Dr. Ben Embarek, had previously deemed the likelihood of transmission to humans through frozen food as being very low. Only a handful of potential incidences of transmission have been documented during the past year.
âIt seems to be extremely rare, and that being the source of the infection seems to be extremely rare, and that is happening in a world where youâre having half a million cases now every day,â Dr. Ben Embarek said in a Jan. 31 interview. âTransposing that onto last year in Wuhan when the virus is not widely circulating in the world and thinking that could be the introduction is not the most likely scenario.â
Some scientists said they understood why the WHO is still considering the frozen-food scenario despite considering it unlikely. âI think the one thing that is really lost in all of this is that the entire investigation canât be separated from political considerations,â said Angela Rasmussen, a virologist at Georgetown Universityâs Center for Global Health Science and Security.
The type of investigation required to fully understand the origin of SARS-CoV-2 âcan take decades,â Dr. Rasmussen said. âThis trip is to lay the groundwork for longer-term studies that are required to look into the origins. This is like the keynote speech at the beginning of the conference, except the conference could take 20 years.â
Stanley Perlman, a professor of microbiology and immunology and pediatrics at the University of Iowa, has been studying coronaviruses for decades. He said regarding the tracing of SARS-CoV-2 to its origins, âIt is hard to know how to get the data to sort this out.â
Based on research on other coronaviruses, Dr. Perlman said the likeliest scenario is that SARS-CoV-2 originated as a bat virus that evolved to infect people. âThe issue in my mind is the virus infects people so well it had to somehow evolve before it even reached the Wuhan seafood market,â he said.
Dr. Perlmanâwho is also a member of The Lancet Covid-19 Commission, an international group set up in July 2020 to address the pandemicâsaid scientists were looking at multiple lines of inquiry to determine how the virus got into the wider population. They are trying to identify bat viruses that could be direct ancestors of the SARS-CoV-2 virus and are interested in testing blood samples for antibodies to SARS-CoV-2 in people who live near caves in Southeast Asia where bats roost, among other approaches.
âIf they had antibodies to SARS-CoV-2 at a time when there was no Covid-19 in that region, thatâs a start at figuring out how it got into the wider population,â Dr. Perlman said, adding that the challenge may be that labs may not retain blood samples going back that far.
WHO researchers had said they would be open to pursuing the likelihood of a laboratory incident. In its final days, the Trump administration claimed to have evidence, which it didnât present to the public, that staff in one of the cityâs major laboratories fell ill with Covid-19-like symptoms in the fall of 2019.
But on Tuesday, the WHO team said it was reassured by hearing of the high biosafety protocols adhered to in the cityâs major labs, including the Wuhan Institute of Virology. The lab also wasnât working with any virus closely linked to the one that causes Covid-19, Dr. Ben Embarek said.
âIt is very unlikely that anything could escape from such a place,â he said on Tuesday. âOf course this is not impossible. It happens once in a whileâ¦These are extremely rare events.â
Chinese health official Liang Wannian, meanwhile, pushed back on the likelihood that Huanan Market was the first place where the outbreak occurred, saying the date of onset of the earliest confirmed case was days earlier than that of the earliest confirmed case in the market. The majority of earlier confirmed cases didnât have any relationship to the market, he said.
Dr. Liang pointed to unpublished studies about cases that preceded Chinaâs, saying other countries could have missed early cases.
Giving weight to Beijingâs theory, Dr. Ben Embarek of the WHO said the virus could have taken a long and convoluted path involving movements across borders before arriving in the Huanan Market. He noted that frozen farm products were sold in the market and called for further studies on the source of animal products in the market as well as research on similar products still being sold elsewhere.
Going forward, WHO officials said they would like to see if early coronavirus cases occurred outside China before the Wuhan market outbreak. Marion Koopmans, a Dutch virologist on the WHO team, said studies suggested there may have been cases in Italy in late November. âWe should really go and search for evidence of earlier circulation wherever that is indicated,â she said.