Donald Trump’s claim that the coronavirus outbreak could have originated in a Chinese laboratory has been labelled “unhelpful” because it risks undermining the public health response to the pandemic.

The US president said on Thursday that he had seen evidence that the virus came from an infectious disease laboratory in Wuhan, and suggested its release was a “mistake”.

But Dr Michael Head, Senior Research Fellow in Global Health at the University of Southampton, said on Friday: “We have good evidence from the genomics research that the virus is not man-made, and the scientific world has very much moved on from this idea.

“It is unhelpful for high-profile individuals to repeat the debunked conspiracy theories, as it undermines the public health response.”

Pandemics happen naturally and it is unnecessary to invoke a conspiracy theory

Brendan Wren, Professor of Medical Microbiology at the London School of Hygiene and Tropical Medicine, also commented.

“Having been to Wuhan a number of times and having had infectious disease researchers from Wuhan working in my labs in London, I don’t believe that there have been any deliberate or nefarious activities with the SARS-Cov-2 virus,” he said.

He added that the city of Wuhan has “excellent state-of-the-art infectious disease facilities”.

“It is generally accepted that the virus has mutated naturally and it has been very difficult to contain within the human community,” he said.

“It should be noted that pandemics occur throughout history and indeed we have them every year.

“These include other viruses and bacteria; for example, antibiotic-resistant bacteria that we know through human activities, such as travel, spread rapidly worldwide.

“Pandemics happen naturally and it is unnecessary to invoke a conspiracy theory.”

Conservative MP Tom Tugendhat, chairman of the House of Commons Foreign Affairs Committee, said the president’s comments “come as no surprise”.

He added: “Though the origin of the virus will be important in a future inquiry, the real need now is for transparency so that we can all learn from each other.

“I hope all countries will share what they know for the safety of their citizens and the whole world.”

The weight of scientific opinion at the moment seems to be fairly and squarely on the side of this being a naturally occurring disease

Professor David Harper, former chief scientist and director-general for public health at the UK’s Department of Health, said theories around the virus have been circulating since January.

He added: “I think it’s one of those situations where there is plenty of room for speculation and there are probably, undoubtedly, different agendas at play.”

But Prof Harper, now a consultant for the Chatham House think-tank, said: “The weight of scientific opinion at the moment seems to be fairly and squarely on the side of this being a naturally occurring disease.”

He said it was “not unheard of” for viruses to escape from laboratories, but emphasised that an independent review is needed on the Covid-19 outbreak, which involves the World Health Organisation.

Dr Jennifer Cole, associate fellow at the Royal United Services Institute for Defence and Security Studies (RUSI), said Mr Trump’s narrative that China was somehow culpable for the outbreak sets a “dangerous political precedent” which does not support international co-operation.

Dr Joshua Moon, research fellow in sustainability research methods in the Science Policy Research Unit at the University of Sussex Business School, said: “If countries are unable to trust one another to contain the spread of the disease, then we will see hoarding of PPE, ‘races’ for vaccines, and competition between countries for resources that will harm the most vulnerable populations.”

Mr Trump’s intelligence agencies are examining the suggestion from the president and his aides that Covid-19 could have been unleashed accidentally from China.

On Thursday, the Office of the Director of National Intelligence issued a statement from the intelligence community saying that it “concurs with the wide scientific consensus that the Covid-19 virus was not man-made or genetically modified”.

It added: “The IC (intelligence community) will continue to rigorously examine emerging information and intelligence to determine whether the outbreak began through contact with infected animals or if it was the result of an accident at a laboratory in Wuhan.”

Speaking at the White House on Thursday, Mr Trump said: “It’s a terrible thing that happened.

“Whether they made a mistake or whether it started off as a mistake and then they made another one, or did somebody do something on purpose.”

“Certainly it could have been stopped,” he said, adding: “They either couldn’t do it from a competence standpoint, or they let it spread.

“It got loose, let’s say, and they could have capped it.”

The Chinese government said any claims that the coronavirus was released from a laboratory are “unfounded and purely fabricated out of nothing”.