Anthony Fauci, America's former Chief Medical Advisor, repeatedly exercised his Fifth Amendment right against self-incrimination at a Senate hearing on Wednesday, refusing to respond to 15 separate questions posed by Republican Senator Rand Paul.
"Under the advice of my attorneys, I will invoke my right under the Fifth Amendment of the Constitution to refrain from answering your questions," Dr Fauci told the Senate Homeland Security and Governmental Affairs Committee, which Mr Paul chairs.
He accused the Kentucky senator of pursuing an "unhinged" crusade to have him jailed.
Mr Paul rejected Dr Fauci's use of the Fifth Amendment, insisting he was not entitled to invoke it and that the preemptive pardon granted by former President Joe Biden would offer no shield.
Mr Paul said: "The committee will have to consider after this hearing what appropriate action should be taken against you for the failure to testify after being directed to do so. It's against the law to obstruct an investigation of Congress. There will be repercussions to your refusal to testify today."
He then ordered one of Dr Fauci's lawyers ejected from the hearing room after declining to recognise the attorney's attempts to interject.
Dr Fauci pointed to what he described as Mr Paul's "obvious obsession with calling for my prosecution, his repeated slanderous comments about me, and recently his publicly releasing my unredacted personal diary aimed at embarrassing and intimidating me."
He argued that the only plausible purpose of the hearing was to coax him into statements that would justify Mr Paul's longstanding public vow to see him end up "behind bars."
Dr Fauci said: "Any reasonable person who has followed his unhinged obsession with me would readily come to the same conclusion."
Anthony Fauci repeatedly exercised his Fifth Amendment right against self-incrimination at a Senate hearing
|REUTERS
The dispute at the heart of the confrontation centres on whether the National Institutes of Health financed gain-of-function research, work that alters pathogens to make them potentially more transmissible or lethal, at a laboratory in Wuhan, China.
Mr Paul has spent years accusing Dr Fauci of lying to Congress about such funding and of concealing the true origins of Covid-19.
Dr Fauci maintains the research in question fell outside the government's formal regulatory definition and insists he has always testified truthfully.
His lawyer, David Schertler, branded Mr Paul's campaign "an obsessive vendetta," calling the allegations "false and disgraceful."
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Rand Paul has for years pledged to see Dr Fauci imprisoned
|REUTERS
Senator Gary Peters, the panel's senior Democrat, condemned the proceedings as a "one-sided" inquiry built around "predetermined conclusions."
The question of where Covid-19 originated remains unsettled.
The FBI assessed in 2023 that a leak from a Wuhan laboratory was the probable cause, while the CIA reached a similar conclusion in January 2025, albeit with "low confidence."
Four other US intelligence agencies and the National Intelligence Council favour natural transmission as the likeliest explanation.
Earlier this week, Mr Paul released 1,141 pages of Dr Fauci's pandemic-era diary entries, which US Health Secretary Robert F. Kennedy Jr said he discovered on government servers and passed to the senator.
Dr Anthony Fauci accused the Kentucky senator of pursuing an 'unhinged' crusade to have him jailed
|REUTERS
President Trump weighed in before the hearing, writing on social media that Dr Fauci's ideas "were CRAZY!"
On Tuesday, the Trump administration introduced a policy prohibiting federal funding for dangerous gain-of-function research.
Former President Biden issued the preemptive pardon on January 19 2025, covering any offences Dr Fauci may have committed since 2014 in connection with Covid-19 or his role leading the National Institute of Allergy and Infectious Diseases, though it does not extend to subsequent conduct.
In April, former adviser to Dr Fauci, David Morens, was charged with concealing federal records relating to research grants and the pandemic's origins; Fauci himself was not indicted.
Representatives for Dr Fauci said the diary entries were consistent with his public statements throughout the crisis.