In his opening statement, Fauci said he would invoke his Fifth Amendment right to not respond to questions, citing Paul's "unhinged obsession" with trying to put him "behind bars."

Dr. Anthony Fauci, the U.S. scientist who helped lead the nation’s COVID-19 pandemic response, is set to face off — again — with a Republican senator probing the origins of the coronavirus.

Sen. Rand Paul of Kentucky subpoenaed Fauci to appear before a Senate committee.