The tweet came two days after Mr. Trump suggested at a briefing that an “injection inside” the human body with a disinfectant could help combat the coronavirus. Despite a lack of scientific evidence, Mr. Trump has long trumpeted various ideas against the virus, like sunlight and warmer temperatures as well as an array of drugs, including the malaria drug hydroxychloroquine, which he has promoted as a “what have you got to lose” remedy. Medical experts have since stepped up warnings about the drugs’ possibly dangerous side effects.

Since Thursday’s assertion, Mr. Trump has been angrily tweeting about the unfairness of his coverage after a damaging news cycle his aides have privately admitted is self-inflicted. Officials have also said that they were skeptical that Mr. Trump would fully retreat from a scenario in which he took questions from reporters, even though he said the two-hour format of the briefings was not worth the effort.

Officials inside the White House are also discussing replacing Alex M. Azar II, the health and human services secretary, after a string of news reports about the administration’s slow response to the coronavirus and a separate controversy about an ousted department official, two senior administration officials said.

Mark Meadows, President Trump’s new chief of staff, is among the aides considering removing Mr. Azar once the height of the coronavirus crisis abates, the officials said. The discussions were first reported by Politico and The Wall Street Journal.

On Saturday, two senior administration officials said that no imminent changes were planned. Among the possible replacements are Seema Verma, the administrator of the Centers for Medicare and Medicaid Services, and Dr. Deborah Birx, a key member of the coronavirus task force.