First COVID patient? A Wuhan vendor
Analysis points to errors in official WHO timeline
A scientist who has pored over public accounts of early COVID-19 cases in China reported Thursday that an influential World Health Organization inquiry had likely gotten the early chronology of the pandemic wrong. The new analysis suggests that the first known patient sickened with the coronavirus was a vendor in a large Wuhan animal market, not an accountant who lived many miles from it.
The report, published Thursday in the prestigious journal Science, will revive, although certainly not settle, the debate over whether the pandemic started with a spillover from wildlife sold at the market, a leak from a Wuhan virology lab or some other way.
The scientist, Michael Worobey, a leading expert in tracing the evolution of viruses at the University of Arizona, came upon timeline discrepancies by combing through what had already been made public in medical journals, as well as video interviews in a Chinese news outlet with people believed to have the first two documented infections.
Worobey argues the vendor’s ties to the Huanan Seafood Wholesale Market, as well as a new analysis of the earliest hospitalized patients’ connections to the market, strongly suggest the pandemic began there.
“In this city of 11 million people, half of the early cases are linked to a place that’s the size of a soccer field,” Worobey said. “It becomes very difficult to explain that pattern if the outbreak didn’t start at the market.”
Several experts, including one of the pandemic investigators chosen by the WHO, said Worobey’s detective work was sound and that the first known case of COVID was most likely a seafood vendor.
But some of them also said the evidence was still insufficient to decisively settle the larger question of how the pandemic began. They suggested the virus probably infected a “patient zero” sometime before the vendor’s case and then reached critical mass to spread widely at the market. Studies of changes in the virus’s genome have suggested that the first infection happened in roughly mid-November 2019, weeks before the vendor got sick.
“I don’t disagree with the analysis,” said Jesse Bloom, a virus expert at the Fred Hutchinson Cancer Research Center. “But I don’t agree that any of the data are strong enough or complete enough to say anything very confidently, other than that the Huanan Seafood Market was clearly a superspreading event.”
Toward the end of December 2019, doctors at several Wuhan hospitals noticed mysterious cases of pneumonia arising in people who worked at the Huanan Seafood Wholesale Market, a dank and poorly ventilated space where seafood, poultry, meat and wild animals were sold. On Dec. 30, public health officials told hospitals to report any new cases linked to the market.
Wuhan authorities said on Jan. 11, 2020, that cases had begun on Dec. 8. In February, they identified the earliest patient as a Wuhan resident with the surname Chen, who fell sick on Dec. 8 and had no link to the market.
Chinese officials and some outside experts suspected that the initially high percentage of cases linked to the market might have been a statistical fluke known as ascertainment bias. They reasoned that the Dec. 30 call from officials to report market-linked illnesses may have led doctors to overlook other cases with no such ties.
In January of this year, researchers chosen by the WHO visited China and interviewed an accountant who had reportedly developed symptoms on Dec. 8. Their influential March 2021 report described him as the first known case.
But Peter Daszak, a disease ecologist at EcoHealth Alliance who was part of the WHO team, said he was convinced by Worobey’s analysis that they had been wrong. “That December the eighth date was a mistake,” Daszak said.
The WHO team never asked the accountant the date his symptoms began, he said. Instead, they were given the Dec. 8 date by doctors from Hubei Xinhua Hospital, who handled other early cases but did not care for Chen.
For the WHO experts, Daszak said, the interview was a dead end: The accountant had no apparent links to an animal market, lab or a mass gathering. He told them he liked spending time on the internet and jogging, and he did not travel much. “He was as vanilla as you could get,” Daszak said.
Had the team identified the seafood vendor as the first known case, Daszak said, it would have more aggressively pursued questions like what stall she worked in and where her products came from.
In Worobey’s revised chronology, the earliest case is not Chen but the vendor, a woman named Wei Guixian, who developed symptoms around Dec. 11.
Worobey found that hospitals reported more than a dozen likely cases before Dec. 30.
He determined that Wuhan Central Hospital and Hubei Xinhua Hospital each recognized seven cases of unexplained pneumonia before Dec. 30 that would be confirmed as COVID-19. At each hospital, four out of seven cases were linked to the market.
By focusing on just these cases, Worobey argued, he could rule out the possibility that ascertainment bias skewed the results in favour of the market.
Still, other scientists said it’s far from certain that the pandemic began at the market.
“He has done an excellent job,” said Dr. W. Ian Lipkin, a virus expert at the Mailman School of Public Health at Columbia University. “But I don’t think we’re ever going to know what’s going on, because it’s two years ago and it’s still murky.”