A team led by the World Health Organization (WHO) that spent four weeks in and around Wuhan in January and February dismissed that theory. But their March report, which was written jointly with Chinese scientists, has been faulted for using insufficient evidence to dismiss the theory.
The new US report concluded analysts would not be able to provide “a more definitive explanation” without new information from China, such as clinical samples and epidemiological data about the earliest cases.
Initially, US spy agencies strongly favored the explanation that the virus originated in nature. But people familiar with intelligence reporting have said there has been little corroboration over recent months the virus had spread widely and naturally among wild animals.
“While this review has concluded, our efforts to understand the origins of this pandemic will not rest,” Biden said. “We will do everything we can to trace the roots of this outbreak that has caused so much pain and death around the world, so that we can take every necessary precaution to prevent it from happening again.”
The World Health Organization’s director-general, Tedros Adhanom Ghebreyesus, has said the group has not ruled out any hypothesis. The Geneva-based organisation is set to impanel a new committee to develop next steps on studying the virus SARS-CoV-2.
But epidemiological experts said the window was closing for any useful data to be collected, particularly from people infected by the disease in 2019 when the virus likely first emerged.