A variety of people around Mr. Trump were previously infected by the virus, including most recently Robert C. O’Brien, his national security adviser who had a mild case before returning to work in August. Others infected include Kimberly Guilfoyle, his son’s girlfriend; a White House valet; Katie Miller, Vice President Mike Pence’s press secretary; as well as some Secret Service agents, campaign advance workers and a Marine in the president’s helicopter unit. Herman Cain, a former Republican presidential candidate and political ally of Mr. Trump’s, died of the coronavirus in July after attending the president’s campaign rally in Tulsa, Okla., where Mr. Cain, like many in the arena, was seen not wearing a mask at least part of the time.
Mr. Trump has repeatedly expressed confidence in public about his own health, saying he was not concerned about being exposed despite his various close calls. “I’m on a stage that’s very far away, and so, I’m not at all concerned,” he said last month, brushing off worries about crowded rallies.
Behind the scenes, though, the self-described germophobe was angry in the spring that his valet, who is among those who serve him food, had not been wearing a mask before testing positive, according to people in touch with him. Mr. Trump privately expressed irritation with people who got too close to him.
According to the president, he began taking the hydroxychloroquine anti-malaria drug proactively around this time and later said it caused no adverse effects. In the days after Ms. Miller’s positive test, Mr. Pence opted to stay physically away from Mr. Trump to avoid a possible exposure, while three top public health officials, including Dr. Anthony S. Fauci, who is on the White House’s coronavirus task force, went into some form of self-quarantine.
The White House ordered some employees to work from home and those who came to work to wear masks except when sitting at their desks an appropriate distance from their colleagues. Just as Mr. Trump and Mr. Pence were being tested every day, those coming into proximity to them were subject to daily tests as well, while other White House employees had tests every several days. But those protocols were soon relaxed and most White House officials were rarely seen wearing masks, at least when the president was present.
While the coronavirus is much deadlier than the flu, the vast majority of people infected by it recover, especially if there is no underlying condition, but the threat climbs with age. If Mr. Trump becomes symptomatic, it could take him weeks to recover.