A CIA whistle-blower's claim that the US spy agency bribed some of its analysts to reject the Covid-19 lab-leak theory is unlikely and part of a politicised debate about the virus' origins, according to top virologists.
The claim, made in testimony to two US House of Representatives committees, is the latest twist in the debate over whether the virus came from a laboratory in the central Chinese city of Wuhan or jumped to humans from an animal host.
According to the Select Subcommittee on the Coronavirus Pandemic and Permanent Select Committee on Intelligence, the whistle-blower, described as a "highly credible senior-level CIA officer", claimed that six of the seven CIA analysts that investigated Covid-19's origins concluded that the virus likely originated from a lab in Wuhan.
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Those six were allegedly offered financial incentives to "change their position".
"According to the whistle-blower, at the end of its review, six of the seven members of the team believed the intelligence and science were sufficient to make a low confidence assessment that Covid-19 originated from a laboratory in Wuhan, China," representatives and committee heads Brad Wenstrup and Mike Turner wrote in a letter to CIA director William Burns.
"The whistle-blower further contends that to come to the eventual public determination of uncertainty, the other six members were given a significant monetary incentive to change their position."
Wenstrup and Turner requested documents on the communication between the agency's Covid-19 Discovery Team and other branches of the government, as well as the payment histories of its members.
But the head of a biosafety lab in China said the claim was part of a much-politicised debate in the United States that resurfaced from time to time, despite the World Health Organization concluding in a report that the lab-leak theory was "extremely unlikely".
"It has become highly politicised in the US with China being a recurring target in partisan debates," the virologist said, adding that the lab-leak theory was used as "a strategic or instrumental tool for pressuring China".
The scientist declined to be named.
A US-based scientist involved in Covid-19 vaccine development also doubted the allegations.