Ms. Hicks, a longtime aide who is one of the president’s closest advisers, was more concerned, colleagues said. She took more precautions than most others and sometimes wore a mask in meetings.
Colleagues said that newcomers to Mr. Trump’s orbit, like Kayleigh McEnany, the White House press secretary, never wore a mask in his presence, in what was interpreted by other staff members as an attempt to please the new boss.
As the months progressed, there were so few reported virus cases in the White House — a valet to the president, a top aide to the vice president and Robert C. O’Brien, the national security adviser, all tested positive — that aides to the president grew even less concerned.
By June, the month before Mr. O’Brien tested positive, the White House had already stopped conducting temperature checks for people entering the complex. Only those aides who were interacting directly with the president received daily tests. Masks remained rare sightings.
The attitude was widespread in the administration. At the Justice Department in May, Attorney General William P. Barr told a New York Times Magazine reporter who arrived in a mask for an interview that “I’m not going to infect you,’’ and then sat by as an aide suggested, twice, that the reporter take the mask off. The reporter did.
Even on Friday, only hours after the president had announced at 1 a.m. on Twitter that he and the first lady had tested positive, the White House was trying to project that it was business as usual. “We had a great jobs report this morning,” Mr. Meadows told reporters at the White House. “Unfortunately, that’s not what everybody is focused on this morning.”
Nonetheless, they made every effort to carry on with a nothing-to-see-here-folks mentality.
Mr. Meadows, who had been in close contact with the president in recent days, arrived at work without a mask, and continued to claim that a mask was not necessary because he had tested negative. (Mr. Meadows wore a mask when he accompanied Mr. Trump, also in a mask, to Walter Reed National Military Medical Center on Friday evening.)