Senator Rand Paul (R-Ky.) and Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, got into a heated exchange this morning during a hearing on the origins of the Covid-19 virus. After Paul alleged that Fauci lied to Congress, the doctor told Paul he didn't know what he was talking about. For access to live and exclusive video from CNBC subscribe to CNBC PRO: https://cnb.cx/2NGeIvi White House chief medical advisor Dr. Anthony Fauci and Sen. Rand Paul traded barbs in a heated exchange at a Senate hearing Tuesday over whether the National Institutes of Health funded controversial research Paul claims could have contributed to the Covid-19 pandemic. Paul grilled Fauci about an NIH funded study that he says qualifies as gain-of-function research, the process of altering a pathogen to make it more transmissible in order to better predict emerging diseases. Fauci previously denied in previous Senate testimony that the NIH has directly funded the research at a lab in Wuhan, China that has come under intense scrutiny as a possible source of the virus. Paul, R-Ky., asked Fauci if he would like to retract that statement from the May 11 testimony, “Fauci, as you are aware it is a crime to lie to Congress.” Fauci, who oversees several NIH research programs as director of the National Institute for Allergy and Infectious Diseases, said he wouldn’t retract his previous statement. “I have not lied before Congress. I have never lied. Certainly not before Congress. Case closed,” Fauci said. He said the study Paul was referring to does not constitute gain-of-function research. “Senator Paul, you do not know what you are talking about, quite frankly, and I would like to say that officially. You do not know what you are talking about,” Fauci said. Paul countered: “No one is saying those viruses caused the pandemic. What we’re alleging is that gain of function research was done in that lab and NIH funded it. You can’t get away from it, it meets your definition and you are obfuscating the truth.” As the two men talked over one another, Fauci interjected that Paul was the one who was obfuscating the truth. “You are implying that what we did resulted in the deaths of individuals,” Fauci responded as he pointed his finger at Paul. “I totally resent that, and if anyone is lying here, senator, it is you.” The Wuhan Institute of Virology has been under scrutiny since the beginning of the pandemic. The World Health Organization led the first phase of an investigation at the lab into the origins of Covid-19 and the possibility it could have leaked from that lab. The WHO has called for further cooperation from the Chinese government in the investigation and said that the agency was denied the raw data necessary for a more complete investigation. Tedros Adhanom Ghebreyesus, director of the WHO, said last week that the agency is asking “China to be transparent, open and cooperate, especially on the information, raw data that we asked for at the early days of the pandemic.” He also said that there was a “premature push” to rule out the possibility of a lab leak. In May, the Senate passed legislation that prohibits U.S. agencies from funding the Wuhan lab, and lawmakers in the House of Representatives have a similar bill in the works. The House Appropriations Committee last week approved an amendment to the the National Institutes of Health funding bill for 2022 that would ban funding to the lab. The bill would also prohibit funding for gain-of-function research in Russia, China, Iran and North Korea. » Subscribe to CNBC TV: https://cnb.cx/SubscribeCNBCtelevision » Subscribe to CNBC: https://cnb.cx/SubscribeCNBC » Subscribe to CNBC Classic: https://cnb.cx/SubscribeCNBCclassic Turn to CNBC TV for the latest stock market news and analysis. From market futures to live price updates CNBC is the leader in business news worldwide. The News with Shepard Smith is CNBC’s daily news podcast providing deep, non-partisan coverage and perspective on the day’s most important stories. Available to listen by 8:30pm ET / 5:30pm PT daily beginning September 30: https://www.cnbc.com/2020/09/29/the-news-with-shepard-smith-podcast.html?__source=youtube%7Cshepsmith%7Cpodcast Connect with CNBC News Online Get the latest news: http://www.cnbc.com/ Follow CNBC on LinkedIn: https://cnb.cx/LinkedInCNBC Follow CNBC News on Facebook: https://cnb.cx/LikeCNBC Follow CNBC News on Twitter: https://cnb.cx/FollowCNBC Follow CNBC News on Instagram: https://cnb.cx/InstagramCNBC https://www.cnbc.com/select/best-credit-cards/ #CNBC #CNBCTV