The president’s latest assertion seemed prompted by his anger with The Washington Post over an interview with Dr. Robert R. Redfield, the director of the Centers for Disease Control and Prevention, published a day earlier. In that interview, Dr. Redfield warned that fall and winter would be taxing on Americans because influenza and the coronavirus would be circulating at the same time.

“He was misquoted,” Mr. Trump said.

“His whole purpose in making the statement was to get a flu shot so that next fall we don’t have such a big season of flu,” the president continued.

But when pressed by reporters, Dr. Redfield said he had been accurately quoted. “There’s a possibility that the assault of the virus on our nation next winter will actually be even more difficult than the one we just went through,” he said in that interview.

On Wednesday, directed by the president to take the stage, Dr. Redfield said, “When I commented yesterday that there was a possibility of next fall and winter, it could be more difficult, more complicated when we had two respiratory illnesses circulating at the same time.”

He added: “I didn’t say that this was going to be worse. I said that this was going to be more difficult.” Taking the lectern to quibble with reporters over the article — which had the headline “C.D.C. Director Warns Second Wave of Coronavirus Is Likely to Be Even More Devastating” — Mr. Trump said that Dr. Redfield did not actually know if “the corona” would come back, and that he had spoken to the doctor at “great length” about his comments.