Unfounded allegations by some U.S. politicians that the COVID-19 virus escaped from a Chinese lab are making it harder for nations to collaborate on ending the pandemic and fueling online bullying, according to a recent news article in the British scientific journal Nature.

"Even without strong supporting evidence," calls to investigate Chinese laboratories have reached a fever pitch in the United States, said the article, adding that for many researchers, the tone of the growing demands is unsettling, which could thwart efforts to study the virus's origins.

While some U.S. politicians groundlessly allege that the coronavirus causing the pandemic was leaked from a Chinese lab, scientists argue that the hypothesis requires a thorough, independent inquiry, the Nature article said.

Citing some scientists, the article added, "The rhetoric around an alleged lab leak has grown so toxic that it's fueling online bullying of scientists and anti-Asian harassment in the United States, as well as offending researchers and authorities in China whose cooperation is needed."

The escalating demands and allegations are contributing to a geopolitical rift at a moment when solidarity is needed, said David Fidler, a global-health researcher at the Council on Foreign Relations, a U.S. think tank.

As U.S. President Joe Biden last week demanded an explanation of the origins of COVID-19 from the U.S. intelligence community, it has become increasingly evident that only politics can substantiate the virus origins story America likes.

This is agreed by multiple American officials and experts, who believe the conspiracy theory that the virus was leaked from a lab is fundamentally rooted in politics, according to an article carried by the Financial Times on Monday.

The Los Angeles Times also pointed out on Wednesday that the "lab leak" allegation is a political conspiracy backed by former U.S. President Donald Trump. 

Current and former officials said an important factor in the Biden administration's acceptance of the lab leak theories, which Democrats used to refute, was that Trump, who embraced the fabrication, was out of office.

The Democrats therefore no longer need to worry that Trump's efforts to vilify China and deflect blame would help him in the election.

The "Wuhan lab leak" allegation is nonsense, which should be thrown out straight away, said British virologist Ian Jones on the origin tracing of COVID-19.

The Washington Post has incurred criticism after making a change to a story last year debunking the conspiracy theory that COVID-19 could have originated from a lab, a media report has said.

The Post article was first published in February 2020 after U.S. Senator Tom Cotton had an interview with Fox News. Originally the headline read, "Tom Cotton keeps repeating a coronavirus conspiracy theory that was already debunked," but it then was changed to walk back on dismissing the theory, Russia's RT website reported on Tuesday.

Critics have accused The Post and other U.S. mainstream media outlets of dealing with the theory for political purposes, while the origin of the virus is still being investigated, the report added.

Director of the U.S. National Institutes of Health Francis Collins appeared to have dismissed the Wuhan lab leak theory of COVID-19 as a "conspiracy" in an email last year, according to recent media reports.

Citing a newly-released email in April 2020 from Collins to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, U.S. magazine Newsweek reported Wednesday that the subject line of Collins' email to Fauci was titled "conspiracy gains momentum."

(With input from Xinhua)