Anthony Fauci, who led the US charge against Covid-19, appeared before Congress on Monday, with Republicans grilling him over the national response to the pandemic.
Dr Fauci, who led the National Institute of Allergy and Infectious Diseases for almost four decades, testified before the House select subcommittee on the coronavirus pandemic – his first time giving public congressional testimony since he left his post in 2022.
The former head of the Niaid, who advised President Joe Biden during the pandemic, became a lightning rod for Republican anger as schools and businesses were forced to close, and mandates for social-distancing and wearing masks were introduced across the country.
The Republican-led subcommittee has spent more than a year assessing the US response to the pandemic and whether Washington-funded research in China may have played a role in the rise of Covid-19.
Theories of the pandemic's origins have been circulating since it was first detected in Wuhan, China, in late 2019.
The most prevalent is that the disease was first contracted by humans at a large seafood and live animal market in the Chinese city.
But others believe Covid-19 came from a leak at a Wuhan laboratory, where it has been alleged that scientists were engaged in "gain of function" research that led to the virus being created.
A major theme of the hearing was the alleged funding of this gain of function research, a much-debated term that entails enhancing a virus in a lab to see how it might behave in the real world.
Republicans have accused Dr Fauci of lying to Congress when he denied in May 2022 that his agency funded gain of function research.
For years, the National Institutes of Health gave grants to New York non-profit group EcoHealth Alliance that used some of the funds to work with a Chinese lab studying coronaviruses commonly carried by bats.
Last month, the government suspended federal funding to EcoHealth Alliance – and proposed barring it from future financing – citing its failure to properly monitor some of those experiments.
But Dr Fauci said "it would be molecularly impossible” for the bat viruses studied with EcoHealth’s funds to be turned into the virus that caused the pandemic.
He also strongly denied suppressing the theory that Covid-19 originated from a lab leak, telling legislators he never influenced research on the origins of the virus.
Dr Fauci said he believed the most probable origin of the pandemic was animal-to-human transmission.
"I've also been very, very clear, and said multiple times, that I don’t think the concept of there being a lab [leak] is inherently a conspiracy theory," he said.
"What is conspiracy is the kind of distortions of that particular subject, like it was a lab leak, and I was parachuted into the CIA like Jason Bourne and told the CIA that they should really not be talking about a lab leak."
As to his handling of the pandemic, he said that when dealing with a novel outbreak, "the scientific process collects the information that will allow you, at that time, to make a determination, a recommendation or a guideline".
"As things evolve and change and you get more information, it is important that you use the scientific process to gain that information and perhaps change the way you think of things, change your guideline and change your recommendation," Dr Fauci said.
He was grilled repeatedly by Republicans on the panel over his stance on Covid safety measures and the exchanges at times became acrimonious,
Representative Marjorie Taylor Greene refused to call Dr Fauci by his honorific, saying "that man does not deserve to have a licence – as a matter of fact, it should be revoked and he belongs in prison".
During the hearing, Dr Fauci faced questions about the credibility of his former agency, after the panel last month revealed emails from a colleague about ways to evade public records laws, including by not discussing controversial issues on government email.
Dr Fauci said in opening remarks that “to the best of my knowledge I have never conducted official business via my personal email".
He also said he has received – and continues to receive – threats and harassment over his handling of the Covid-19 pandemic.
"There have been everything from harassment by emails, texts, letters, of myself, my wife, my three daughters," Dr Fauci said.
"There have been credible death threats leading to the arrests of two individuals and credible death threats means someone who clearly was on their way to kill me."
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