Dr. Anthony Fauci said "I sleep fine" in a new interview where he was pressed about any possible role U.S. funding could have played in the hotly debated origins of the coronavirus pandemic.

"I sleep fine. I sleep fine," Fauci told the New York Times. "And remember, this work was done in order to be able to help prepare us for the next outbreak. This work was not conceived by me as I was having my omelet in the morning."

Fauci, the medical face of the U.S. coronavirus response, has long issued heated denials that the National Institutes of Health had any role in the Wuhan "lab leak" theory for the origins of the pandemic. In a lengthy interview, Fauci said the NIH's grants to the nonprofit EcoHealth Alliance, which were then funneled to the Wuhan Institute of Virology, couldn't possibly have resulted in viruses that ended up becoming SARS-CoV-2.

"All of the intelligence groups agree that this was not an engineered virus," he said. "And if it’s not an engineered virus, what actually leaked from the lab? If it wasn’t an engineered virus, somebody went out into the field, got infected, came back to the lab and then spread it out to other people. That ain’t a lab leak, strictly speaking. That’s a natural occurrence."

The Times' David Wallace-Wells replied, "Even in that case, the research itself is still playing a role. But when you say everyone agrees it was not an engineered virus — I don’t think they do."

Anthony Fauci

WASHINGTON, DC - JANUARY 11: Dr. Anthony Fauci, Then-Director of the NIAID, responds to questions from Sen. Rand Paul (R-KY) at a Senate Health, Education, Labor, and Pensions Committee hearing on Capitol Hill on January 11, 2022 in Washington, D.C. (Photo by Greg Nash-Pool/Getty Images) (Greg Nash-Pool/Getty Images)

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Fauci went on to suggest "gain of function," a term that refers generally to manipulating viruses for research purposes, has multiple meanings.

"When the NIH resumed funding gain-of-function research after a three-year safety review, they did so under what was called the ‘P3CO’ framework, under which research with pathogens known to be infectious and dangerous to humans was held to a higher level of scrutiny," he said.

He said the lab leak notion was improbable, claiming the viruses they worked with at the lab did not match the one that sparked the pandemic. 

"What gets conflated is that the NIH funded them, therefore you are liable for the lab leak if it’s a lab leak," he said. "It had nothing to do with what we did, because the viruses were unable to be made into SARS-CoV-2."

Wallace-Wells was not entirely dissuaded.

Dr. Anthony Fauci

Dr. Anthony Fauci, then-Director of the National Institute of Allergy and Infectious Diseases and the Chief Medical Advisor to the President, gives an update on the Omicron COVID-19 variant during the daily press briefing at the White House on December 01, 2021 in Washington, DC. ( (Photo by Anna Moneymaker/Getty Images))

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"I’m not suggesting that the work described in that particular EcoHealth grant led to the pandemic. But we know that there was a lot of other work being done in Wuhan," he said. "And if I were you, and I was going to sleep every night thinking that there was even some very small chance that the virus came from a laboratory doing the kinds of research that I had helped promote and fund over the last few decades, I think that might weigh on me a bit, even if I was absolutely sure I had done everything I had done with the best intentions." 

"Now you’re saying things that are a little bit troublesome to me," Fauci responded. "That I need to go to bed tonight worrying that NIH-funded research was responsible for pandemic origins."

"I’m not saying you need to do anything," Wallace-Wells said. "I’m putting myself in your shoes and telling you what I think it would mean to me to really believe there’s a chance, even a very small one, that this pandemic was the result of a lab leak."

"Well, I sleep fine. I sleep fine," Fauci said. "And remember, this work was done in order to be able to help prepare us for the next outbreak. This work was not conceived by me as I was having my omelet in the morning. It is a grant that was put before peer review of independent scientists whose main role is to try to get data to protect the health and safety of the American public and the world."

Fauci led the National Institute of Allergy and Infectious Diseases from 1984 to 2022 and also served as Chief Medical Adviser to President Biden until last year.

When asked if a hypothetical lab leak origin could compromise future gain of function research, Fauci warned that this would effectively wipe flu vaccines out of existence.

"Some want to pass a law: All gain-of-function should be stopped," Fauci said. "But if all gain-of-function stops, you will have no vaccines for flu. You will have no vaccines for any of the other diseases, because all of that manipulates a virus or a pathogen to gain a certain function to be able to make a vaccine."

Wuhan Institute of Virology

FILE - A view of the P4 lab inside the Wuhan Institute of Virology is seen after a visit by the World Health Organization team in Wuhan in China's Hubei province on Feb. 3, 2021.  (AP Photo/Ng Han Guan)

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The debate over the origins of COVID-19 has evolved since 2020, with the lab-leak theory gaining increased credence in mainstream circles. Fauci has said it can't be discounted but has long maintained a natural occurrence is the more likely explanation.

The Department of Energy said earlier this year with "low confidence" that it believed the virus had leaked from the Wuhan lab. Proponents of the theory have derided critics who called such ideas preposterous and even racist in 2020, in part because Republicans like Donald Trump espoused them.