From ‘open minded’ to ‘underwhelming,’ mixed reactions greet latest COVID-19 origin report

“Further studies needed.” That’s the main message in a preliminary report released today by a scientific advisory group convened by the World Health Organization (WHO) to clarify the cloudy origin of COVID-19. But in stark distinction to a report from an earlier WHO committee, which drew controversy in 2021 by all but dismissing that SARS-CoV-2 might have escaped from a lab in Wuhan, China, this panel recommends more investigations into the lab-leak scenario possibility.

“All hypotheses must remain on the table until we have evidence that enables us to rule certain hypotheses in or out,” said WHO’s director-general, Tedros Adhanom Ghebreyesus, in a speech today to member states. “This make[s] it all the more urgent that this scientific work be kept separate from politics.” Yet keeping politics out may be impossible: Panel members from China, Russia, and Brazil noted in a footnote that they saw no reason for more research on whether the virus leaked from the Wuhan Institute of Virology, long the target of suspicions—and conspiracy theories—because it studied bat coronaviruses.

The panel, formally known as the Scientific Advisory Group for the Origins of Novel Pathogens (SAGO) and established in October 2021, has 27 members from different countries who have diverse areas of expertise. Maria Van Kerkhove, the WHO official overseeing SAGO, stressed at a press conference this morning that the group was not asked “to actually find the origins of the COVID-19 pandemic” but instead to “advise WHO on the studies that are necessary” to understand the emergence of dangerous new pathogens, including SARS-CoV-2. In contrast to the earlier study on the pandemic’s origin by a “joint commission,” which sent an international team of scientists to meet with colleagues in China, SAGO did not visit Wuhan and other cities there as part its probe.

Initial reactions to the report’s less than conclusive message have been mixed. “It’s open-minded, summarizes what is known but also importantly what still isn’t known, pays attention to source and provenance of data, and suggests some reasonable concrete next steps,” says Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center who has argued that the lab-leak possibility deserves more serious attention than it has received.

Filippa Lentzos, a social scientist at King’s College London who specializes in biothreats, says the report “could definitely have gone further.” She wanted to see a blunter appraisal of China’s lack of transparency. “The report is not outright critical of China’s origin investigations, but the ‘ideal’ studies they present demonstrate significant omissions in the Chinese response,” Lentzos says.

“Underwhelming” was the verdict of Michael Worobey of the University of Arizona, even though the report prominently features his own work: two studies recently posted as preprints that provide evidence for “zoonotic” spillover of the virus from animals to humans at a Wuhan market. Coronaviruses found in horseshoe bats in China and Laos have about 96% genetic similarity to SARS-CoV-2—a significant evolutionary distance, which leads many scientists to suspect an “intermediate host” harbored the virus before it reached people. SAGO’s 46-page report spotlights the same possibility Worobey’s work supported: that the virus spilled over from this host at the Huanan Seafood Market in Wuhan, which sold many mammals as well as seafood and had the first cluster of cases.

Echoing some of the earlier panel’s conclusions, the SAGO report recommends closely examining environmental samples taken from the market and doing “investigations and audits” of farms that provided it with animals susceptible to SARS-CoV-2. It suggests that international labs study blood samples of the farmers, which might reveal antibodies to SARS-CoV-2 or other clues.

Although Chinese researchers have not found any evidence of SARS-CoV-2 in tens of thousands of sampled animals, the report goes to some length to say those findings prove little—none of the samples included racoon dogs and red foxes, two susceptible species sold at the market, for example. “The investigations in China should be better focused to include relevant mammalian target species,” the report notes. It also suggests studies be done of carnivores raised for their fur in China—a huge industry that includes racoon dogs, minks, and civets—as well as preserved meats and other animal products stored from before the outbreak.

One of the few pieces of fresh information in the report came from Chinese researchers, who responded to a request from SAGO and provided new data on blood samples taken from 40,000 people in Wuhan before the first COVID-19 cases surfaced in December 2019. Although 200 tested positive for antibodies to SARS-CoV-2, those antibodies could not neutralize the virus in a confirmatory test, suggesting these were false positives. The report recommends more aggressively looking for early cases in the records of 233 Wuhan medical clinics and also reviewing pharmacy records between September and December 2019 to see whether any unusual purchases provide signals of early clusters of cases.

A dozen studies from Europe and the United States have offered evidence of SARS-CoV-2 or antibodies in biological or sewage samples taken before December 2019. Independent attempts to validate these studies so far have failed, but Chinese officials have highlighted them to suggest the pandemic originated elsewhere, and SAGO is still reviewing those data. Its report only notes that “the significance of these findings remains unclear.”

The three SAGO members who challenged the decision to include the lab-leak possibility contended in a footnote that “there is no new scientific evidence” to question the joint commission’s earlier conclusion that this was “extremely unlikely.” “I want to have something much more solid than just a hypothesis,” says Carlos Morel, a parasitologist at the Oswaldo Cruz Foundation in Rio de Janeiro, one of the three dissenters. “If you don’t have evidence, why should I discuss it?”

At the press conference, SAGO’s chair, virologist Marietjie Venter of the University of Pretoria, stressed that unlike the joint commission report, her panel did not rank the various possibilities. “But at this stage, the strongest evidence is still around a zoonotic transmission,” Venter said.

Van Kerkhove closed the press conference by addressing the elephant in the corner: Can WHO, which is beholden to its member states and has little power to force China or any other country to cooperate, get it to do the studies recommended in the report? “We’re under no illusions that we can keep all of the politics out, but we will do our damnedest to keep focused on what needs to be done here,” she said. “We will continue to do everything we can until these questions are answered.”