TOPSHOT - A security guard stands outside the Huanan Seafood Wholesale Market where the coronavirus was detected in Wuhan on January 24, 2020 - The death toll in China's viral outbreak has risen to 25, with the number of confirmed cases also leaping to 830, the national health commission said. (Photo by Hector RETAMAL / AFP) (Photo by HECTOR RETAMAL/AFP via Getty Images)
WHO report on origin of Covid-19 explained ahead of release
03:37 - Source: CNN
CNN  — 

Theories about a laboratory leak being the source of the coronavirus pandemic sound like something out of a comic book, one virologist says.

Dr. Robert Garry of Tulane University and other virologists have been publishing studies for a year that demonstrate SARS-CoV-2 originated naturally in animals and is unlikely to have been engineered in a lab.

Genetic study shows the virus carries all the messy hallmarks of nature and none of the fingerprints that would have been left behind by laboratory manipulation.

“What are the things that argue against a lab leak? There are a whole lot of them,” Garry told CNN.

Yet last week, former US Centers for Disease Control and Prevention Director Dr. Robert Redfield added his voice to those saying the virus most likely leaked from a laboratory in China – perhaps by accident.

“I am of the point of view that I still think the most likely etiology of this pathogen in Wuhan was from a laboratory, escaped,” Redfield told CNN Chief Medical Correspondent Dr. Sanjay Gupta.

Redfield, a virologist, presented no evidence to back up his assertion. And while he joins non-experts such as US Sen. Tom Cotton and former Secretary of State Mike Pompeo, his former colleague Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, disagrees, as do a swath of other experts in infectious diseases.

And a World Health Organization report released Tuesday says the lab leak theory is the least likely of four scenarios its investigators considered. Most likely: the virus spread from its natural host, probably a bat, to another animal and then to people.

But the US government criticized the report as incomplete, further feeding Redfield’s theory. And WHO Director-General Tedros Adhanom Ghebreyesus said he did not think the WHO team’s lab assessment was extensive enough. “Further data and studies will be needed to reach more robust conclusions,” Tedros told a briefing Tuesday.

“Although the team has concluded that a laboratory leak is the least likely hypothesis, this requires further investigation, potentially with additional missions involving specialist experts, which I am ready to deploy.”

What bothers most scientists CNN spoke to was Redfield’s description of what he says he thinks happened.

“Most of us in a lab, when trying to grow a virus, we try to help make it grow better, and better, and better, and better, and better, and better so we can do experiments and figure out about it. That’s the way I put it together,” Redfield said.

“That’s the way it would be in a movie or some sort of a thriller or a comic book,” retorts Garry, who studies viruses in the field and in the lab and who helped write a study published in March of last year that showed the virus arose naturally.

“It is improbable that SARS-CoV-2 emerged through laboratory manipulation of a related SARS-CoV-like coronavirus,” Kristian Andersen, an infectious disease researcher at the Scripps Research Institute in La Jolla, California, along with Garry and other experts, reported in Nature Medicine in March 2020.

They found the receptor binding domain of the coronavirus spike protein – that’s the structure that attaches the virus to human cells – “is not ideal.” It could have been better designed, they found. “This is strong evidence that SARS-CoV-2 is not the product of purposeful manipulation,” they wrote.

They also looked for evidence that a process called reverse genetics had been used to alter an existing virus to make it look more like SARS-CoV-2 – the virus that causes Covid-19. But they found “irrefutably” that was not done.

“There’s just a lot of things about it that look perfectly natural,” Garry said. “It’s just messy enough to look natural.”

Joel Wertheim, an evolutionary biologist at the University of California San Diego who has studied the coronavirus, says much the same thing.

“There is nothing about this virus’s genome that wouldn’t come about in nature,” Wertheim told CNN.