Former top US health official Anthony Fauci has refused to answer questions at a US Senate hearing discussing the origins of the Covid-19 pandemic, saying he feared Republicans would try to use his testimony to prosecute him for perjury.

He invoked the Fifth Amendment to the US Constitution, which says no individual can be “compelled in any criminal case to be a witness against himself”.

Days before the hearing, Republican Senator Rand Paul released Fauci’s pandemic-era diary entries, in which he mused about fame and Covid’s origins.

Contradicting himself under oath could have been legally perilous. Fauci noted he had testified about Covid and its origin at several congressional hearings.

“Although it pains me to do so because of the respect I have for the legislative branch of government … under the advice of my attorneys, I will invoke my right under the Fifth Amendment of the constitution to refrain from answering your questions,” said, Fauci, 85, former leader of the National Institute of Allergy and Infectious Diseases (NIAID).

Taking the Fifth is not an admission of guilt – it is designed to protect individuals against coercion, mistakes, and unfair shifting of the burden to provide proof of wrongdoing.

Fauci, in his statement, said Paul’s “obvious obsession” with prosecuting Fauci that led him to decline to answer questions.

“The only conclusion I can reach is that the sole reason he is calling me before this committee is to get me to say something – anything – that could vindicate his repeated public pledges that I end up, in his words, ‘behind bars,’” Fauci said.

Paul, who worked as an eye surgeon before joining Congress, continued questioning Fauci despite his refusal to answer. He repeatedly invited Fauci to “apologise” and said the committee would vote next week on a resolution holding Fauci in contempt of Congress.

Republicans asked him about shifting health guidance, which changed during the pandemic as health officials learned more about the disease. Fauci has previously defended his policy positions.

One of Fauci’s lawyers who was seated next to him repeatedly tried to interject during Paul’s questioning. Paul directed a security guard to remove him from the room.

Republicans have long accused Fauci of concealing information about the pandemic from the public, or lying about its dangers. Fauci, in previous testimony to lawmakers after retiring from government in 2022, has denied any wrongdoing, calling the allegations “simply preposterous”.

The origins of the pandemic have been a matter of strong debate in the US, including between President Donald Trump, who was in office when it began in 2020, and public health officials, including Fauci.

During the hearing on Wednesday, Trump took to social media and called Fauci “crazy”.

“I said from the beginning that the Virus came from the Wuhan Laboratory in China. Fauci strongly disagreed, always trying to protect China,” Trump said.

In the hearing, Paul suggested that while Fauci said publicly that Covid originated naturally, he privately believed the virus originated in a medical lab. The senator has repeatedly promoted the lab-leak theory that Covid came from China’s Wuhan Institute of Virology.

The World Health Organization in 2025 said the natural-origins theory – the virus spilling over from animals to people – was the “best supported” idea from the available evidence but said until more information emerges, origin determination is “inconclusive”.

Fauci’s diary entries reflect openness at the start of the pandemic to two possible theories about Covid’s origins – including natural origins and a lab leak – before he appears to become more convinced it had a natural origin.

In one entry from February 2020 discussing a conference call between Covid scientists, Fauci says the doctors did not have “total agreement” about where the virus came from.

Later, Fauci writes he “is almost certain that the virus evolved naturally from a species jump, even though… I keep an open mind about the possibility of a lab leak”.

“[J]ust because two alternatives are possible that does not mean that they are equally probable,” Fauci wrote.

At Wednesday’s hearing, Fauci’s decision not to testify enraged Republicans, including Senator Ron Johnson who angrily told Fauci that he planned to push to subpoena him in an effort to require him to answer lawmakers’ questions.

Several Democrats came to Fauci’s defense, including Senator Maggie Hassan, who said the hearing was “designed to entrap” Fauci.

Fauci has faced death threats during and after the coronavirus pandemic. He was one of the most trusted members of the US government during its response to the pandemic as scientists were trying to learn about the virus as quickly as possible.

Fauci and Trump frequently sparred over the handling of the pandemic, including when Trump suggested unproven treatments.

Before he left office, former Biden issued a pre-emptive pardon for Fauci, who had stayed on as his chief medical officer.

“The issuance of these pardons should not be mistaken as an acknowledgment that any individual engaged in any wrongdoing, nor should acceptance be misconstrued as an admission of guilt for any offense,” Biden said at the time. (BBC)

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