Dr. Anthony Fauci, the U.S. government's top infectious diseases expert, said the Chinese scientists at the Wuhan Institute of Virology (WIV) that the U.S. National Institutes of Health (NIH) collaborated with over the years are "qualified" and "highly respected."

His latest comments come when the western media are hyping another round of conspiracy theories that the novel coronavirus was made and leaked from a lab, an allegation that has been repeatedly refuted and condemned by global scientists since last year.

The NIH has been working with the WIV on bat coronavirus research. Because of the scientific collaboration, Fauci was dragged into a recent debate with Senator Rand Paul, a Kentucky Republican, who accused the NIH of funding "gain-of-function" with the Chinese lab.

Gain-of-function research involves altering a pathogen, usually a bacterium or virus, in a way that increases its transmissibility, in order to better understand the pathogen and develop vaccines.

In an interview with Neil Cavuto on Fox News, Fauci resolutely denied the accusation and defended the integrity of the Chinese scientists.

"The purpose of the research was very, very clear. It was to try to determine what was out there in the bat population that might be ultimately risky for us. It was done in the context of trying to find out what the precise environmental bat source was of SARS-CoV-2 so that we could prevent SARS-CoV-2," he said.

"If you look at the research that was done, it was research that was highly recommended by peer review, our United States peer reviews. It got a very high score in the peer review system," he noted.

He stressed that the research was done by qualified people. "… you're dealing with qualified, highly respected Chinese scientists. So it isn't what was made out to be about dealing with really, really bad people. Because those scientists were very well-respected in the scientific community internationally," he said.

Debate between Fauci and Paul

In May, when Paul alleged that the NIH offered grants to the Wuhan lab for "gain-of-function" experiments, Fauci told him that "The NIH has not ever and does not now fund gain-of-function research in the Wuhan Institute of Virology."

Paul brought the issue up again during a Senate hearing on Tuesday, citing a November 2017 scientific study co-authored by WIV researcher Shi Zhengli and other Chinese scientists.

"This paper that you are referring to was judged by qualified staff up and down the chain as not being gain-of-function," Fauci replied.

"Paul, you do not know what you are talking about, quite frankly, and I want to say that officially. You do not know what you are talking about," the expert told the senator.

It's not the first time that Paul has clashed with the medical expert on COVID-19. In March, he told Fauci that vaccinated people wearing masks was just "theater." He has repeatedly dismissed CDC guidance on vaccines and restrictions on public gatherings.