Dr. Anthony Fauci, the head of the National Institute of Allergy and Infectious Diseases, said in a panel on Thursday that the U.S. should be ready to “hunker down” in its fight against the coronavirus and indicated that the fall and winter will not be easy.

“We’ve been through this before,” he told a panel of doctors from Harvard Medical School, according to the Hill. “Don’t ever, ever underestimate the potential of the pandemic. And don’t try to look at the rosy side of things.”

WHITE HOUSE DEFENDS TRUMP AFTER WOODWARD BOOK CLAIMS HE SAID CORONAVIRUS 'DEADLY,' DESPITE PUBLICLY DONWPLAYING IT

The Associated Press reported that winter is ending in the Southern Hemisphere and countries noted that steps to prevent the virus’ spread also limited the flu outbreak. The report said that it is not a certainty that the Northern Hemisphere will have the same outcome.

CLICK HERE TO GET COMPLETE CORONAVIRUS COVERAGE

“This could be one of the worst seasons we’ve had from a public health perspective with COVID and flu coming together. But it also could be one of the best flu seasons we’ve had,” Dr. Robert Redfield, director of the U.S. Centers for Disease Control and Prevention, told The Associated Press.

Fauci appeared on Fox News earlier this week to respond to comments President Trump made to journalist Bob Woodward about playing down the virus’ potency.

"The Daily Briefing," host John Roberts asked Fauci if he thought Trump had played down the threat of the virus.

GET THE FOX NEWS APP

"No, I didn't," Fauci responded. "I didn't get any sense that he was distorting anything. I mean in my discussions with him, they were always straightforward about the concerns that we had. We related that to him. And when he would go out, I'd hear him discussing the same sort of things. He would often say, 'We just got through with a briefing with the group from the task force,' and would talk about it. So it may have happened, but I have not seen that kind of distortion."

Fox News' Sam Dorman and the Associated Press contributed to this report