There is growing international pressure to learn more about the origins of the pandemic that has killed more than 3 million people worldwide and US President Joe Biden last week ordered his aides to find answers. The WHO reacted to Biden’s announcement that intelligence agencies were pursuing rival theories, including the possibility of a laboratory accident in China, by saying the search was being “poisoned by politics”. Covid was first identified in the central Chinese city of Wuhan in December 2019, while Italy’s first patient was detected on February 21 last year in a small town near Milan.

China’s foreign ministry spokesman Wang Wenbin has said there is “no evidence” the disease originated from Wuhan.

Speaking at a press conference, he said: “Recently, many international experts and scholars have questioned and criticised and US practice of politicising the issue of origin-tracing.

“Australian scientist Dominic Dwyer, a member of the WHO expert team, said there was no evidence to back up the lab escape theory.

“Pete Daszak, a member of the expert team and an American scholar, said that he and other scholars who had been to Wuhan for origin-tracing studies had published a wealth of data supporting a ‘natural spillover’ and pointed out there was a complete lack of data suggested a lab incident.

READ MORE: Kim Jong-un executes man for illegally selling South Korean films

“Daszak dismissed US ‘intelligence reports’ as ‘political, not scientific’.

“Angela Rasmussen, a virologist at Columbia University, said that ‘the most frustrating thing about the topic of SAR-CoV-2 origins has been the credulous way the media has treated this as a debate between two equally plausible hypotheses. This is more like the debate over climate change.’

“There’s the data and then there’s false equivalence.”

It comes as samples from a study suggesting the coronavirus was circulating outside China by October 2019 have been re-tested at the World Health Organization’s (WTO) request, two scientists who led the Italian research said.

However, a study published last year suggested antibodies to either the virus or a variant were detected in Italy in 2019.

That prompted Chinese state media to suggest the virus might not have originated in China, although the Italian researchers stressed the findings raised questions about when the virus first emerged rather than where.

“The WHO asked us if we could share the biological material and if we could re-run the tests in an independent laboratory.

We accepted,” Giovanni Apolone, scientific director of one of the lead institutions, the Milan Cancer Institute (INT), said.

The WHO’s request has not previously been reported.