Fauci: We need to keep an 'open mind' about the lab-leak theory of the coronavirus pandemic's origins

• Dr. Anthony Fauci said researchers should stay open-minded about the coronavirus pandemic's origins.
• Some have speculated the deadly COVID-19 virus leaked from a lab in Wuhan, China.
• Fauci said a "fair, open investigation" was needed to determine the real source of the pandemic.

Dr. Anthony Fauci said Thursday that scientists and researchers should keep an "open mind" about the speculative theory that the coronavirus pandemic was caused by an accident at a Chinese lab, though he reiterated that it was "more likely" the virus that causes COVID-19 first spread from an animal to a person.

Fauci, the director of the National Institute of Allergy and Infectious Diseases, spoke on "Morning Joe" on Thursday after several of his emails were made public by BuzzFeed News and The Washington Post via a Freedom of Information Act request.

In some emails from April 2020, he and the National Institutes of Health's director, Francis Collins, discussed the theory that the coronavirus might have first started spreading from a laboratory in China.

"The situation is that we didn't know, and we still don't know what the origin is," Fauci told "Morning Joe," after he was asked whether he believed that the lab-leak theory was a conspiracy theory.

"If you look historically in the way things rolled out, we all felt - and still do - that it's more likely to be a natural jumping from an animal reservoir to a human," Fauci said. "However, since we don't know that for sure, you've got to keep an open mind."

Three out of every four emerging infectious diseases come to us from other species, including other coronaviruses like the ones that cause SARS and MERS.

'Very unlikely that anything could escape from such a place'

As long as the mystery of the pandemic's origin remains unsolved, the question will persist.

Fauci said that while there was increasing interest in the lab-leak theory, "the evidence is very sparse."

He went on to say there should be a "fair, open investigation" into the COVID-19 pandemic's origins to "make sure this doesn't happen again."

An investigation in Wuhan five months ago by a World Health Organization team concluded that the coronavirus most likely spilled over to people from animals - possibly at wildlife farms in southeastern China - but the group found no definitive proof of that. Nor could it rule out a lab leak, because investigators weren't able to do a full audit of labs in Wuhan, spending just hours at each facility.

Questions about a such a leak generally center on the Wuhan Institute of Virology, a high-level biosafety lab where some scientists had been studying coronaviruses before the pandemic. The institute's staff did not share all of its records or safety logs with the WHO team. The organization's director-general, Tedros Adhanom Ghebreyesus, said in March that he did "not believe that this assessment was extensive enough."

Three years ago, US officials visiting Wuhan sent a pair of memos to the State Department warning of inadequate safety measures at the lab. The institute seems to have made rigorous changes since then, though, and the WHO team was satisfied with the lab's protocols.

One of the WHO investigators who visited the lab, Peter Ben Embarek, said the institute housed a "state-of-the-art lab," which is part of the reason his team thinks it's "very unlikely that anything could escape from such a place."

Jonna Mazet, an epidemiologist at the University of California at Davis who has worked directly with researchers from the Wuhan Institute of Virology, told Insider last year the lab's safety measures were above reproach.

Mazet worked with the staff there to develop and implement a "very stringent safety protocol," she said.