Among the events that appear to be linked to the spread of the virus are the announcement of Amy Coney Barrett's nomination the Supreme Court on Sept. 26 in the White House Rose Garden and Tuesday's presidential debate in Cleveland.
Trump announced his positive COVID-19 about 1 a.m. Friday.
His physician, Dr. Sean Conley, said in a Saturday morning briefing that it had been 72 hours since his diagnosis, which would put it at midday Wednesday. Conley later walked back the timeline he presented during the news conference and confirmed Trump was diagnosed Thursday evening.
Since Wednesday, Trump has attended events in multiple states, potentially exposing dozens of people to the coronavirus. Since there's also an incubation period during which a person shows no symptoms after first contracting COVID-19, it's unclear where the president picked up the virus.
Sens. Mike Lee, R-Utah, and Thom Tillis, R-N.C., each tested positive after sitting near each other at the Barrett announcement. They serve on the Senate judiciary committee, which is expected to hold hearings on her nomination Oct. 12.
Many guests at the event did not practice social distancing and few wore masks.
Lee and Tillis were among at least seven people attending the event who have since tested positive, including Trump, first lady Melania Trump, University of Notre Dame President the Rev. John Jenkins, former White House counselor Kellyanne Conway and a reporter.
Barrett tested negative for COVID-19 on Friday, though she and her husband, Jesse, had recovered from the virus over the summer.
Senate Republican leader Mitch McConnell said the senators' diagnoses raised the prospect that several other senators have been an exposed, which could make it difficult to hold in-person hearings for Barrett. Hearings for her confirmation are expected to begin in less than two weeks, less time than the Centers for Disease Control and Prevention suggests that people with or exposed to COVID-19 quarantine.
Sen. Ron Johnson. R-Wis., also announced Saturday that he tested positive for the coronavirus after being exposed earlier this week, though it's unclear where he contracted it, according to his office.
Johnson's not on the judiciary committee, but depending on when the Senate holds a full vote on Barrett's confirmation, his illness could impact his ability to be physically present for that.
McConnell on Saturday said all Senate floor proceedings would be postponed until Oct. 19, but that Barrett's confirmation hearings would take place Oct. 12 as planned.
"Since May, the judiciary committee has operated flawlessly through a hybrid method that has seen some senators appear physically at its hearings while other members have participated virtually," he said in a statement.
"The committee has utilized this format successfully for many months while protecting the health and safety of all involved. Certainly all Republican members of this committee will participate in these important hearings."
McConnell later tweeted that he finished speaking with the president, who was "in good spirits," and that he planned to move "full steam ahead," with the confirmation hearings.
Senate Democratic leader Chuck Schumer, D-N.Y. and Sen. Dianne Feinstein, D-Calif., have called for Senate Judiciary Chairman Lindsey Graham R-S.C., to delay the confirmation hearings, saying that health must take priority.
"There is bipartisan agreement that virtual confirmation hearing for a lifetime appointment to the federal bench is not an acceptable substitute," the two senators said. "It's critical that Chairman Graham put the health of senators, the nominee and staff first -- and ensure a full and fair hearing that is not rushed, not truncated and not virtual."
News of the first COVID-19 case linked to the White House came Thursday evening when senior adviser Hope Hicks was confirmed to have the virus. Trump said he and the first lady underwent testing in reaction to Hicks' diagnosis and learned of their diagnosis late Thursday or early Friday.
He participated in a roundtable discussion with supporters as well as a fundraiser at Trump National Golf Club in Bedminster, N.J., on Thursday evening.
All of his events were canceled Friday after his diagnosis became public.
Trump's campaign manager, Bill Stepien, and former New Jersey Gov. Chris Christie also tested COVID-19 positive early Saturday. They, along with Conway, helped Trump prepare for his Tuesday debate with Democratic presidential nominee Joe Biden.
Biden and his wife, Jill Biden, have since tested negative. Vice President Mike Pence and second lady Karen Pence also tested negative, as has Trump's son, 14-year-old Barron Trump.
Republican National Committee Chairwoman Ronna McDaniel was diagnosed with the virus Wednesday and has been experiencing mild symptoms. She was last with the president on Sept. 25, a representative said.
Three White House reporters tested COVID-19 positive Friday, according to a series of memos from the White House Correspondents Association and other White House reporters are "self-isolating pending diagnostic testing."
Trump was transported to Walter Reed hospital in Maryland on Friday evening.