Conspiracy theories claiming COVID-19 was engineered in a lab as part of a biological attack on the United States have been gaining traction online in recent weeks, but a new study on the origins of the virus has concluded that the pandemic-causing strain developed naturally.

An analysis of the evidence, according to the findings first published in the scientific journal Nature Medicine, shows that the novel coronavirus "is not a laboratory construct or a purposefully manipulated virus," with the researchers concluding "we do not believe that any type of laboratory-based scenario is plausible."

"There’s a lot of speculation and conspiracy theories that went to a pretty high level," Dr. Robert Garry, a professor at the Tulane University School of Medicine and one of the authors of the study, told ABC News, "so we felt it was important to get a team together to examine evidence of this new coronavirus to determine what we could about the origin."

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PHOTO: This handout illustration image taken with a scanning electron microscope shows SARS-CoV-2 (yellow)also known as 2019-nCoV, the virus that causes COVID-19isolated emerging from the surface of cells (blue/pink) cultured in the lab. (National Institutes of Health/AFP via Getty Images) More

Dr. Francis Collins, the director of the National Institutes of Health, supported the study’s findings, writing on his blog, "This study leaves little room to refute a natural origin for COVID-19."

Researchers concluded that the novel coronavirus is not a human creation because it does not share any "previously used virus backbone." It likely arose, the study said, from a recombination of a virus found in bats and another virus, possibly originating from pangolins, otherwise known as scaly anteaters.

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COVID-19 is 96% identical to a coronavirus found in bats, researchers said, but with a certain variation that could explain what has made it so infectious.

"We know from the study of other coronaviruses that they’re able to acquire this [variation] and they can then become more pathogenic," Garry told ABC News. "This is a good explanation as to why this virus is so transmittable and has caused this pandemic."

PHOTO: This handout illustration image taken with a scanning electron microscope shows SARS-CoV-2 (yellow)also known as 2019-nCoV, the virus that causes COVID-19isolated emerging from the surface of cells (blue/pink) cultured in the lab. (Handout/National Institutes of Health/AFP via GettY Images) More

The mutation in surface proteins, according to Garry, could have triggered the outbreak of the pandemic, but it’s also possible that a less severe version of the illness was circulating through the population for years, perhaps even decades, before escalating to this point.

"We don’t know if those mutations were picked up more recently or a long time ago," Garry told ABC News. "It’s impossible to say if it actually was a mutation that triggered the pandemic, but either way, it would have been a naturally occurring process."

And while many believe the virus originated at a fish market in Wuhan, China, Garry said that is also a misconception.

"Our analyses, and others too, point to an earlier origin than that," Garry said. "There were definitely cases there, but that wasn’t the origin of the virus."

What to know about coronavirus:

How it started and how to protect yourself: coronavirus explained

What to do if you have symptoms: coronavirus symptoms

Tracking the spread in the US and Worldwide: coronavirus map

Sorry, conspiracy theorists. Study concludes COVID-19 'is not a laboratory construct' originally appeared on abcnews.go.com