Dr. Anthony Fauci, the head of the U.S. National Institute of Allergy and Infectious Diseases, has emerged as President Donald Trump‘s fact-checker, contradicting overly optimistic claims about the novel coronavirus.

Fauci recently discredited Trump’s claim on Friday that hydroxychloroquine, an anti-malarial drug, would be a promising treatment to the coronavirus.

“Many of the things out there are what I have called ‘anecdotal reports’,” Fauci corrected. “The information that you’re referring to specifically is anecdotal. It was not done in a controlled clinical trial, so you really can’t make any definitive statement about it.”

While the drug has shown some promise being used individually by doctors, it is unclear exactly how effective it is against COVID-19. However, some worry that Trump’s statements regarding the drug may provide Americans a “false sense of hope.”

During Friday’s White House briefing, NBC News correspondent Peter Alexander asked Trump:
“Is it possible …. that your impulse to put a positive spin on things may be giving Americans a false sense of hope and misrepresenting the preparedness right now?”

Trump has directed the Food and Drug Administration to look into the drug, but it has not been approved for coronavirus treatment.

Regarding his correction Friday, Fauci told The New York Times that he did not want to “embarrass” Trump saying, “I don’t want to act like a tough guy, like I stood up to the president. I just want to get the facts out. And instead of saying, ‘You’re wrong,’ all you need to do is continually talk about what the data are and what the evidence is.”

In an interview with Science Magazine published Sunday, Fauci said that even though he has publicly corrected the president, Trump continues to listen to what he has to say.

“Well, that’s pretty interesting because to his [Trump’s] credit, even though we disagree on some things, he listens,” Fauci said. “He goes his own way. He has his own style. But on substantive issues, he does listen to what I say.”

Asked whether he would ever refer to the coronavirus as the “Chinese Virus,” a term coined and used by Trump, Fauci said he never has and he never will.