(NBC News) Sen. Rand Paul, R-Ky., and Dr. Anthony Fauci, one of the government's top public health experts, got into a heated exchange at a Senate hearing Tuesday after Paul accused Fauci of lying to Congress about the role the National Institutes of Health played in funding research in Wuhan, China.
"Senator Paul, you do not know what you're taking about, quite frankly, and I want to say that officially." Fauci said. "You do not know what you're talking about."
The director of the National Institute of Allergy and Infectious Diseases was responding to Paul's claim that the NIH funded gain-of-function research — which looks to increase the transmissibility or pathogenesis of an organism in order to study disease — at the Wuhan Institute of Virology. Fauci said Paul's accusation was false, prompting a further exchange on what constitutes such research.
While it was not a new accusation from Paul, the senator implied Tuesday that Fauci had previously lied to Congress and was aware of what the Wuhan lab was doing with grant money that came from the NIH.
"Senator Paul, I have never lied before the Congress and I do not retract that statement," Fauci said in rebuking Paul's claim, adding that the issue had been evaluated many times by qualified people.
"We don't know that it did come from the lab, but all the evidence is pointing that it came from the lab, and there will be responsibility for those who funded the lab, including yourself," Paul claimed, referring to the coronavirus.
"I totally resent the lie that you are now propagating, senator, because if you look at the viruses that were used in the experiments that were given in the annual reports that were published in the literature, it is molecularly impossible" for those viruses to result in the coronavirus, Fauci responded.
President Joe Biden in May asked U.S. intelligence agencies to "redouble" their efforts to determine the origins of the coronavirus after it was unable to reach a “definitive conclusion” on the matter.
Paul was the first senator known to have contracted the coronavirus when he tested positive in March of last year, and he said earlier this year that he wouldn't be getting the vaccine since he already had the virus.
The senator, a steadfast opponent of Covid mitigation measures and mask mandates, has clashed with Fauci before on other pandemic-related issues.
"This is a pattern that Senator Paul has been doing at multiple hearings based on no reality," Fauci said. "I have not lied. Case closed."