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A fruit vendor walks past the Huanan Seafood Wholesale Market, now closed, on 11 January. The market is one of the sites a 10-member international committee hopes to visit during its stay in Wuhan, China.

NICOLAS ASFOURI/AFP via Getty Images

After aborted attempt, sensitive WHO mission to study pandemic origins is on its way to China

Sciences COVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation.

On Monday evening, Peter Daszak drove to John F. Kennedy International Airport in New York City for the second time this year, hoping to fly to Wuhan, China. Daszak, a disease ecologist at the EcoHealth Alliance, is part of an international team charged by the World Health Organization (WHO) with investigating the origins of SARS-CoV-2, which was first discovered in Wuhan.

The previous week he got as far as Doha, Qatar, before the trip began to unravel. With new variants of the coronavirus spreading across the world, China was imposing additional safety requirements for incoming passengers—with no exceptions for invited scientists. “We tried for a day and a half to see if we could fix the bureaucracy,” Daszak says. “I was sleeping on the floor in the VIP lounge: very nice food, but no bed.” He ended up flying home.

China has received intense criticism for not earlier allowing a transparent probe of SARS-CoV-2’s origin, and the aborted attempt to get the mission underway, widely seen as more foot dragging, created another international stir; WHO Director-General Tedros Adhanom Ghebreyesus said he was “very disappointed.”

But now, the team is on the move again. Its members are gathering in Singapore this week and may board a plane straight to Wuhan today or tomorrow, where they will have to quarantine, individually, for 14 days. (One member, David Hayman of Massey University in New Zealand, decided to stay home because he could not get a booking in a designated hotel for another compulsory 2-week quarantine upon his return.)

But mission members caution against unrealistic expectations that they may soon find the animal host from which SARS-CoV-2 jumped into humans, or make some other breakthrough discovery. “It’s not like you go there, take samples from 20 bats and a civet cat and then you understand the epidemiology,” says WHO panel member Fabian Leendertz, a wildlife veterinarian at the Robert Koch Institute in Berlin, who is not traveling to China for family reasons but will participate virtually. There is too little time to do actual science on these trips, says Linfa Wang, an emerging disease specialist at Duke-NUS Medical School in Singapore who is not part of the team but took part in a similar for mission for severe acute respiratory syndrome in 2003. Instead, the group will collaborate with Chinese scientists who do the work on the ground. “The mission is to improve the communication and increase exchange,” he says.

The team is working against a tense political background. U.S. President Donald Trump has faulted the Chinese government for failing to contain what he calls “the China virus,” while China is actively spreading unproven claims that the virus originated outside its borders. It took WHO many months to put together the group and agree with China on the terms of the mission. “WHO is jammed between China and the U.S.,” Wang says.

At a press conference on Monday, WHO’s Mike Ryan pleaded with people not to not frame the scientific study of SARS-CoV-2’s emergence in terms of determining guilt. “Understanding the origin of disease is not about finding somebody to blame,” he said. “We are looking for the answers here that may save us in the future, not culprits.” The composition of the group—10 scientists from 10 countries, including Russia, Qatar, and Vietnam—reflects the enormous global impact of COVID-19. “This is so sensitive, they really have to balance it,” Wang says.

Over the past few months, the international experts and their Chinese counterparts have had four virtual meetings, led by WHO epidemiologist Peter Ben Embarek, to sift through existing data, says Marion Koopmans of Erasmus Medical Center in the Netherlands. “What exactly is known? What could have happened? What are potential other sources of information? What has been tested [in China]? If not, what can be tested there? What is still available?” That work will continue while team members are quarantined in Wuhan, she says, but with daily calls instead of weekly. After that, they are hoping to spend 2 weeks visiting various sites in Wuhan and return home before China shuts down for Lunar New Year celebrations in mid-February.

Understanding the origin of disease is not about finding somebody to blame. We are looking for the answers here that may save us in the future, not culprits.

Mike Ryan, World Health Organization

Scientists feel pretty confident that SARS-CoV-2 came from bats, but they don’t know which species. And the question is whether it jumped straight to humans or via another animal. “The intermediate host is more important than the ultimate origin, because the intermediate host gave the virus to humans,” Wang says.

That’s why one of the stops will be at the Huanan Seafood Wholesale Market, where many of the first cases appear to have occurred. Although a Chinese investigation reportedly did not find any animals positive for the virus there, 69 environmental samples were positive, 61 of them from the market’s western wing where wild boar, raccoons, and other mammals were sold. Researchers sequenced three viral genomes from these samples and found them to be virtually identical to those from patients at the time, suggesting these animals may have acted as intermediate hosts.

The mission may also visit the Wuhan Institute of Virology (WIV), which is part of the Chinese Academy of Sciences. Most scientists reject the conspiracy theory that the virus was concocted there, but the WHO team will need to consider the hypothesis that the virus was accidentally released from the lab, says epidemiologist Marc Lipsitch of the Harvard T.H. Chan School of Public Health: “Otherwise, the report won’t have done its job.”

Daszak has worked closely with WIV for many years and has shared a $3.1 million grant from the U.S. National Institutes of Health before it was canceled by the Trump administration; some have argued this creates a potential conflict of interest. Daszak agrees the theory of a lab escape needs to be looked at, but there are limits, he says. “Some of the more anti-China rhetoric that’s out there, about, we need to go into the lab and look at the video cameras, this sort of thing, that’s not realistic, that’s not what happens.” (Daszak chairs of a second team of researchers looking at the pandemic’s origins as part of The Lancet COVID-19 Commission. “I’m going to be extremely disciplined on keeping the two separate,” he says.)

Chinese officials have actively promoted the theory that the virus did not originate in their country at all. They have pointed to two studies suggesting the virus was circulating in Italy as early as late November, or even September 2019. But those data have yet to be confirmed. “When we make these claims that kind of go against what most of the evidence is, we really need strong evidence to back up those claims,” says virologist Emma Hodcroft of the University of Basel. (WHO has reached out to both groups and is setting up collaborations to have another lab confirm the results.) But even if the Italian data are correct, that does not mean the virus originated in Europe; it could have come from China earlier than scientists knew.

The WHO panel’s biggest problem will be that the Chinese government carefully chooses what it gets to see, says Alexandra Phelan, a lawyer at Georgetown University who specializes in global health policy. “No matter how hard local and international scientists try,” she says, “the reality is that the Chinese leadership is in an international propaganda battle.” Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations in New York City, agrees that politics makes it “very challenging to do the work independently, transparently, and thoroughly.” But the transfer of power next week in Washington, D.C., might make things a bit easier, he adds. If President-elect Joe Biden manages to cool down the rhetoric with China, “That could create a more favorable environment for the scientists to do their work.”