The pandemic — death knell to more than 6 million people and perhaps as many as 20 million indirectly — still hides its origin. While scientists have struggled mightily to confront threats to human health, attempts to discover how it all began and why remain skimpy and inconclusive. The outbreak started in China, but leaders there covered up the human transmissibility of the virus at first, then mounted a propaganda campaign insisting it originated outside China.
What really happened in Wuhan, and why? The answers could help prevent and plan for a future pandemic.
One school of thought is that the coronavirus jumped from bats to humans, perhaps with an intermediate animal host, a zoonotic spillover event, which has happened often in the past. Another is that research on bat coronaviruses at the Wuhan Institute of Virology, including dangerous “gain of function” experiments, resulted in a laboratory accident or inadvertent leak. Perhaps there was a combination of both, such as a researcher handling bats who became infected and then spread the virus.
Two new research papers in Science revive the questions. One, by University of California San Diego’s Jonathan E. Pekar and colleagues, concludes that there were two jumps of the virus to humans in late 2019. The second paper, by University of Arizona professor Michael Worobey and colleagues, focuses on the Huanan Seafood Wholesale Market in Wuhan, which sold wildlife and farmed animals, live and butchered. Scrutinizing the location of early human cases of the virus, including 155 with reliable longitude and latitude data, the researchers found a high density of cases near, and surrounding, the market. The paper concludes the market was “the early epicenter” of the pandemic and suggests the virus “likely emerged from the live wildlife trade in China.”
In a preprint in February, the University of Arizona professor claimed to have found “dispositive evidence” that the virus spilled over from the live wildlife trade. His revised, peer-reviewed paper is more cautious, saying the research “does not establish that the pandemic originated” in the market. Events “upstream of the market, as well as exact circumstances at the market, remain obscure,” he acknowledges.
And so much is obscure. In the early chaos of the outbreak, sick patients were turned away from hospitals and not properly counted, so the population plots might not contain the whole story. After the pandemic picked up steam in early 2020, China made no known effort to go back and look for additional early cases from November and December, which might have provided important clues about the origin. Environmental samples point to animals being sold in a corner of the market, but there are no live animal samples to identify which species carried the virus. The Worobey team drew population data from the joint China-World Health Organization mission to China, which published its findings in 2021. At a news conference in Wuhan at the end of the mission, the WHO team leader, Peter Ben Embarek, called a lab leak “extremely unlikely,” but he later told Danish television he was under pressure from China to dismiss the hypothesis, which it calls “a false claim.” A second WHO group is now investigating.
We hope they — or others — get to probe on the ground in Wuhan and elsewhere. China’s leaders should end the stonewalling and open the doors.