Pompeo said on Wednesday that US authorities have made multiple formal requests for viral isolates and information about “patient zero”.

“Trying to obtain the earliest viral RNA in the pandemic is an important endeavour, but I just don’t understand the need to do that with the State Department first, and publicly with conspiracy theories that are still around,” said David Larsen, a public health professor at Syracuse University who has studied the spread of malaria and other infectious diseases.

Larsen said that there were other reasons for China to share the viral isolates beyond tracing the pandemic’s initial path, but argued that such exchanges would likely have been more productive if left to the two countries’ scientists instead of the US State Department.

“From a future prevention standpoint, it’s important to understand where the virus came from,” Larsen said.

“Our science is not very good at figuring out which viruses circulating in other animals might potentially jump over to humans and then become able to circulate among humans.”