Scientists investigating the pandemic’s origins as part of a mission to China were unable to provide much clarity Tuesday on where the virus began.
The leader of the World Health Organization’s team, Peter Ben Embarek, told journalists that after a month-long mission to the country, the investigation didn’t significantly change previous understanding.
“Did we change dramatically the picture we had beforehand? I don’t think so,” said Embarek. “Did we improve our understanding and did we add details to that story? Absolutely.”
The politically fraught investigation has faced difficulties from its inception. Two investigators initially had to return home after setting out for China when it emerged that Beijing hadn’t finalized permissions for the scientists to enter the country.
The findings from the investigation indicate that while the virus may have originated in zoonotic transmission, the exact host remains to be identified.
What the investigation did find is that there’s no evidence of substantial spread before December 2019 in Wuhan. Scientists looked at everything from analysis of cough and cold medications bought at pharmacies to samples from a blood databank, explained Liang Wannian, head of the expert panel of COVID-19 Response of the China National Health Commission.
The investigators also found that while there was substantial transmission associated with the Huanan market in Wuhan, transmission was also occurring elsewhere in Wuhan at the same time.
“We don’t know the exact role of the Huanan market,” said Embarek.
The earliest confirmed case from December 8, 2019, had no association with the market.
The team investigated several other theories, including the chance the virus was introduced through frozen farmed wild animals or resulted from a lab incident. The only theory that appears to have been completely abandoned is the latter, said Embarek, calling it “extremely unlikely.”
Embarek also partially discounted the possibility of a direct jump from bats, noting that Wuhan isn’t close to bat environments. Further work is needed to look at tracing products that were in the market and understanding possible transmission from frozen wild animals to market environments, he added.