Current and former senior health officials with direct knowledge of phone calls, emails and other communication between the agencies said on Saturday that meddling from Washington was turning widely followed and otherwise apolitical guidance on infectious disease, the Morbidity and Mortality Weekly Reports, into a political loyalty test, with career scientists framed as adversaries of the administration.

They confirmed an article in Politico Friday night that the C.D.C.’s public morbidity reports, which one former top health official described on Saturday as the “holiest of the holy” in agency literature, have been targeted for months by senior officials in the health department’s communications office. It is unclear whether any of the reports were substantially altered, but important federal health studies have been delayed because of the pressure…

In an email obtained by Politico and confirmed by a person with direct knowledge of the message, Mr. Alexander accused C.D.C. scientists of trying to “hurt the president” with the reports, which he referred to as “hit pieces on the administration.” Mr. Alexander asked Dr. Robert R. Redfield, the C.D.C. director, to edit reports that had already been published, which he believed overstated the risks of the virus for children and undermined the administration’s efforts to encourage schools to reopen.

Mr. Caputo and Mr. Alexander also tried to stop the publication of a report — issued last week after a delay — on use of the malaria drug hydroxychloroquine, an unproven treatment that Mr. Trump and conservative allies have heralded and used as a kind of litmus test of resistance to scientific consensus. In discussions with the C.D.C., they questioned the political beliefs of the report’s authors.