• The female seafood vendor first became ill on Dec. 11, 2019
  • Wuhan health authorities initially said that the first case was an accountant who fell ill on Dec. 8, 2019
  • Michael Worobey said the accountant likely suffered from a dental problem that needed hospitalization

An Arizona-based scientist believes he has found the “patient zero” of the COVID-19 pandemic after poring over public accounts of the earliest cases of the virus.

In a report published in the journal Science on Thursday, Michael Worobey, a leading expert in tracing the evolution of viruses at the University of Arizona, said he believes the first known case to be a female seafood vendor at a Wuhan animal market. The vendor became ill on Dec. 11, 2019. 

"[T]he most early symptomatic cases were linked to Huanan Market — specifically the western section where raccoon dogs were caged — provides strong evidence of a live-animal market origin of the pandemic," Worobey wrote in the study.

Worobey said he first came to the conclusion after coming across timeline discrepancies in medical journals. He also combed through video interviews of people believed to be the first two documented cases of COVID-19. 

Health authorities in Wuhan in February 2020 said the first known case of COVID-19 was a male accountant who fell ill on Dec. 8, 2019. The accountant, whose identity was not identified, had no link to the market. 

Worobey argued that the accountant had likely suffered from a dental problem on Dec. 8. He also noted that hospital records showed that man had COVID-19 on Dec. 16, 2019, less than a week after the seafood vendor fell ill. 

The scientist said the accountant likely contracted COVID-19 at the hospital during his dental emergency through community transmission after the virus spread from the wet market. 

Several experts said Worobey’s analysis was sound and agreed that the first case was most likely a seafood vendor at the market. However, some also said the evidence Worobey presented was insufficient to answer the origins of the COVID-19 pandemic. They said the virus likely infected another individual sometime before the vendor fell ill. 

“I don’t disagree with the analysis,” Jesse Bloom, a virologist at the Fred Hutchinson Cancer Research Center, told The New York Times. “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 super-spreading event.” 

Bloom also cited studies of changes in the genome of the novel coronavirus that suggested the first infection happened in mid-November 2019. Worobey was one of the scientists who conducted a study on the virus’ genome. 

The first known outbreak was linked to a wet market in Wuhan, central China The first known outbreak was linked to a wet market in Wuhan, central China Photo: AFP / Noel CELIS