Once dismissed by the mainstream media as a "fringe" and "debunked" theory, the suggestion that the devastating coronavirus leaked from a Wuhan superlab instead of jumping from animals to humans is no longer considered outlandish.

Former Centers for Disease Control and Prevention (CDC) Director Robert Redfield said last week he believed the pathogen unintentionally escaped from a lab in Wuhan, a city known as a center for Chinese viral studies. The Wuhan Institute of Virology has also been known to perform experiments on bat coronaviruses.

A repeatedly delayed joint World Health Organization-China investigation declared the lab leak theory "extremely unlikely" last week, but experts are already questioning its conclusions due to the influence of the notoriously deceitful Chinese government.

Even the head of the World Health Organization, Dr. Tedros Adhanom Ghebreyesus, much maligned for his obseqiousness toward China at the outset of the pandemic, said the research team’s assessment on whether the virus entered the human population following a laboratory incident was not "extensive enough" and requires further investigation.

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Numerous media outlets dismissed the idea last year, however, when it was initially asserted by Sen. Tom Cotton, R-Ark. The pushback against Cotton occurred during denunciations of Trump administration figures framing COVID-19 as a "Chinese" or "Wuhan" virus.

Stories published by The Washington Post ("conspiracy theory that was already debunked"), New York Times ("fringe theory"), HuffPost ("debunked fringe theory"), and The Daily Beast ("conspiracy theory") aggressively disputed Cotton's hypothesis. 

MSNBC host Brian Williams cited the Post on his program on Feb. 17, 2020, saying, "Arkansas Republican Senator and loyal Trump ally Tom Cotton has waded into trouble by commenting on the coronavirus, which is proving virulent and deadly and is spreading fast. The Washington Post headline puts it this way: 'Tom Cotton keeps repeating a coronavirus conspiracy theory that was already debunked.'"

Vanity Fair linked the theory to efforts by President Donald Trump to attack China over the virus outbreak, declaring it "added a scary new layer to Donald Trump’s blame-China strategy."

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HuffPost reported last January that Cotton made "unfounded allegations" against the Chinese government for failing to stop the spread of the coronavirus, one of the most embarrassing examples of a liberal news outlet parroting pro-China propaganda to ding a conservative. Indeed, reporting later showed China's authoritarian government silenced physicians and whistleblowers in the critical early weeks of the pandemic.

The outlets at times conflated Cotton's belief it could have come from a lab with the notion China purposefully engineered a bio-weapon, which Redfield and Cotton have said they do not believe occurred. Rather, Redfield said the coronavirus's highly effective transmission ability suggested to him it had been experimented on in a laboratory.

Liberal media figures, such as the Washington Post's Jennifer Rubin and Daily Beast's Molly Jong-Fast, delighted in piling on Cotton.

"The far right has now found its own virus conspiracy theory," left-wing CNN host Fareed Zakaria said on March 8, 2020, of Cotton's remarks. Three days later, CNN's John Vause declared Cotton's comments "misinformation" while interviewing infecious disease expert Dr. Anthony Fauci.

"Well, I'm not going to comment about what any individual says. But in general, I can tell you that theories that are not based on evidence and facts often can really mislead people," Fauci said at the time.

The Post later reported in 2020 that the U.S. State Department warned in 2018 of inadequate safety measures at the Wuhan Institute of Virology, where bat coronavirus experiments were taking place.

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Cotton told Fox News Primetime" Monday that the "best evidence" to him, while circumstantial, indicates the virus originated from an "accidental breach" in a Wuhan lab.

"Tens of millions of Americans have had their lives upended over the last year. They have lost jobs. Their businesses have closed," he said. "They have lost loved ones. I don't think those Americans want to simply turn the page and let bygones be bygones. We need to get to the bottom of what happened in Wuhan and how the Chinese Communists unleashed this plague on the world and we need to hold them accountable."

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China has promoted conspiracy theories of its own about the pandemic's origins, including accusing the U.S. military of having a hand in its spread.

The U.S. intelligence community continues to believe the virus originated in animals and did not leak from a lab.

Fox News' Alexandra Hein contributed to this report.