WASHINGTON _ President Donald Trump was rushed to the hospital for treatment for COVID-19 on Friday evening, less than 24 hours after he tested positive for the coronavirus, and the White House said he would remain at Walter Reed National Military Medical Center for at least a few days as concerns mounted that he could face a severe risk from the deadly disease.
The president's surprise diagnosis, and worsening condition, sent shock waves across a country already reeling from the pandemic, and bracing for a tumultuous presidential election next month that could hinge on Trump's handling of a public health crisis that has killed more than 208,000 Americans this year.
As senior aides, lawmakers and the Pentagon sought to reassure a nervous public, Trump and the first lady, who also tested positive, spent the day isolated in the White House residence. At sunset, the president walked on his own to the Marine One helicopter on the South Lawn of the White House and was flown to the hospital in suburban Maryland.
Wearing a navy suit, blue tie and a black mask, the president flashed a thumbs-up but didn't stop to speak to reporters. After he arrived at the hospital at 6:29 p.m. Eastern time, Trump tweeted a video message thanking people for their support.
"I think I'm doing very well, but we're going to make sure that things work out," he said.
In a letter released by the White House, Trump's physician, Dr. Sean P. Conley, said the president "remains fatigued but in good spirits." White House officials said the president was suffering "mild symptoms" but offered few details.
Kayleigh McEnany, the press secretary, sought to downplay the danger, suggesting Trump was simply shifting his workplace. "Out of abundance of caution, and at the recommendation of his physician and medical experts, the president will be working from the presidential offices at Walter Reed for the next few days," she said in a statement.
First lady Melania Trump was not hospitalized given her symptoms. Conley said she had a mild cough and a headache.
McEnany said the president has not transferred his authority to Vice President Mike Pence. His office said Pence tested negative for the coronavirus on Friday, alleviating immediate concerns about the presidential line of succession should Trump become incapacitated and unable to perform official duties.
Trump first announced that he and the first lady had tested positive in a tweet shortly before 1 a.m. Eastern time Friday. After that, his normal activities ground to a halt.
He didn't tweet or take part in a planned conference call with governors to discuss the pandemic. His campaign also canceled several announced rallies and events this week featuring the president or members of his family, although some events may be held virtually as the campaign moves into its final month.
Trump's doctor said in his letter that the president was taking zinc, vitamin D, famotidine, which is used to treat heartburn, melatonin, which is a sleeping pill, and a daily aspirin. He said Trump also was given a single 8 gram dose of Regeneron's experimental antibody cocktail REGN-COV2 "as a precautionary measure."
Regeneron is still conducting clinical trials on the drug cocktail, and three days ago the New York-based company announced initial findings that indicated its "greatest treatment benefit was in patients who had not mounted their own effective immune response" and were at "greater risk for prolonged symptoms."
Medical experts were alarmed that the president was given a drug still in the testing phase, and said it suggested his condition may be more serious than officials have disclosed.
"You wouldn't do that with somebody who is just having an uncomplicated case," said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security.
Adalja also said it wasn't surprising that Trump was hospitalized since he is 74 and overweight, two high-risk factors for COVID-19, and reports that he is battling a fever.
"It's not just a mild case if he's getting hospitalized," he said. "It's likely to have more careful monitoring and more therapy and bloodwork and having nurses and doctors around."
Former Vice President Joe Biden, the Democratic nominee who pounded Trump's handling of the pandemic when they met Tuesday on the debate stage in Cleveland, tested negative for the virus Friday, according to his doctor.
Dr. Jill Biden, his wife, also tested negative. Both said they were praying for the president and his family.
It wasn't clear if two more scheduled presidential debates would come off as planned, events that could give Trump an opportunity to rebound from his widely panned performance in Tuesday's free-for-all.
Pence is scheduled to participate in a debate Wednesday in Utah with Sen. Kamala Harris, the Democratic vice presidential nominee. The event may carry greater importance for voters given the concerns about Trump's health.
Trump's activities in the past week may pose a challenge for contact tracing.
In addition to the debate, he hosted two rallies, participated in a dozen events and interacted with numerous supporters and donors, many of whom did not wear masks. Health officials in Minnesota, Pennsylvania and New Jersey urged people who attended his events to get tested if they felt ill.
Republicans struggled to keep their legislative plans on track, including a controversial Supreme Court nomination, while Pentagon officials tried to allay concerns about the nation's military readiness.
At the White House, some staffers suddenly wore face masks after months of eschewing the practice to placate the president, and senior aides sought to calm public anxieties after Trump's predawn tweet Friday.
White House chief of staff Mark Meadows said Trump showed "mild symptoms" of COVID-19 but was in "good spirits" and energetic. "His first question to me this morning was, 'How is the economy doing?'"
The first lady posted a brief thank you message to well-wishers on social media.
"I have mild symptoms but overall feeling good," she tweeted. "I am looking forward to a speedy recovery."
Although no one else in the president's inner circle had tested positive, Meadows made clear that he expects the outbreak to spread because the virus is often most contagious before symptoms appear.
"I fully expect that as this virus continues to go on other people in the White House will certainly have a positive test result," he told reporters.
It's unclear where the president contracted the virus, but one of his closest aides, Hope Hicks, tested positive on Thursday. She flew with him recently on Air Force One and Marine One, the president's helicopter.
Meadows sought to explain Trump's decision to travel Thursday afternoon to a fundraiser at his golf club in New Jersey after officials knew about Hicks' test results. He claimed staffers didn't learn about them until Trump was lifting off the South Lawn in the afternoon, although another aide, speaking on the condition of anonymity, said Hicks' test had occurred hours earlier.
Ronna McDaniel, the Republican National Committee chairwoman, announced that she also had tested positive for COVID-19. She often travels with the president and was last with him on Sept. 25 when he traveled to Virginia.
Former New Jersey Gov. Chris Christie, one of a half-dozen advisers closely involved with helping the president prepare for his debate Tuesday with Biden, told ABC News on Friday that "no one was wearing masks in the room when we were prepping the president."
Biden, the Democratic nominee, said he would pray for the president and first lady.
"Jill and I send our thoughts to President Trump and First Lady Melania Trump for a swift recovery. We will continue to pray for the health and safety of the president and his family," Biden tweeted.
The Bidens' primary care physician, Dr. Kevin O'Connor, said they both underwent PCR testing Friday "and COVID-19 was not detected."
"Thank you to everyone for your messages of concern," Biden tweeted later. "I hope this serves as a reminder: wear a mask, keep social distance, and wash your hands."
Trump had mocked Biden during their debate for limiting his public appearances and frequently wearing masks, as public health experts recommend.
"I don't wear masks like him," Trump said. "Every time you see him, he's got a mask."
On Capitol Hill, Republicans insisted that the presidential health crisis would have little impact on the effort to hold confirmation hearings before the election for conservative Judge Amy Coney Barrett to fill a vacancy on the Supreme Court.
Senate Majority Leader Mitch McConnell, R-Ky., tweeted that he and Trump spoke by phone Friday and "talked business _ especially how impressed Senators are with the qualifications of Judge Barrett. Full steam ahead with the fair, thorough, timely process that the nominee, the Court, & the country deserve."
Hours earlier, McConnell sounded more circumspect in a radio interview, calling the virus "the biggest enemy" to a swift confirmation process. Confirmation hearings are scheduled to start Oct. 12, but McConnell said they may conducted, at least in part, remotely.
But Democrats seized on the fact that Sen. Mike Lee, R-Utah, a member of the Judiciary Committee, also tested positive for coronavirus on Friday, days after he met in his office with Barrett, who was diagnosed with the virus earlier this year but recovered.
Later Friday, another Republican member of the Judiciary Committee, Sen. Thom Tillis, said that he also had tested positive and would self-isolate for 10 days. Tillis is locked in a tight reelection race in North Carolina.
Sen. Chris Murphy, D-Conn., called for delaying the confirmation hearings.
"We can't move forward on Amy Coney Barrett or anything else until we know whether there was some super-spreader event at the White House or at that debate, which has resulted in perhaps more Senate staff and members than Mike Lee contracting this disease," he said on MSNBC.
House Speaker Nancy Pelosi, D-Calif., who is third in the line of succession to the presidency, said she received the news of Trump's positive diagnosis "with great sadness." She said she was tested "out of an abundance of caution" and her results were negative.
"Maybe now that people who see the president of the United States with all the protection that he has and the first lady still having this exposure, it might be, as you say, a learning experience," she said on MSNBC. "But more than learning, it has to be something that is acted upon."
Defense Secretary Mark Esper, who last met with Trump on Sunday and is traveling overseas, was awaiting coronavirus test results Friday. Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, tested negative, according to Jonathan Hoffman, a Pentagon spokesman.
He said the appearance of two E-6B Mercury aircraft, which can serve as airborne command posts in emergencies, on both the Pacific and Atlantic coasts just before Trump's announcement shortly after midnight were on "preplanned missions" and the timing was "purely coincidental."
"There's been no change to (Defense Department) alert levels," Hoffman said. "The U.S. military stands ready to defend our country and interests. There's no change to the readiness or capability of our armed forces. Our national command and control structure is in no way affected by this announcement."
Ashish Jha, dean of the Brown University School of Public Health, said Trump's diagnosis will create a challenge for tracing his contacts because of the virus's incubation period, which can last days before it is detected.
"Anyone near Ms. Hicks from Monday on, President from Tuesday on should quarantine," he tweeted. "I'd go back, test everyone near President from at least Saturday on to see if we can identify source."