Here’s what you need to know:
President Trump received a promising experimental drug to treat Covid-19 on Friday, according to a memo from his doctor, and later went to Walter Reed National Military Medical Center for what was expected to be a stay of a few days.
In a brief video message the president tweeted shortly after arriving at Walter Reed, he looked tired. He declared that he is “doing very well” and suggested that he was visiting the hospital only as a precaution.
“I think I’m doing very well, but we’re going to make sure that things work out,” Mr. Trump said in the 18-second video, filmed in the White House shortly before his departure for the hospital. “The first lady is doing very well,” Mr. Trump added.
The message was Mr. Trump’s first tweet since he announced early Friday that he and his wife, Melania Trump, had tested positive for the virus.
Mr. Trump returned to Twitter late Friday night, writing in a short tweet: “Going well, I think! Thank you to all. LOVE!!!”
The president had showed no visible sign of difficulty as he walked to Marine One on the White House Lawn, wearing a blue suit and tie and a mask. He made no comments to reporters clustered nearby, but gave a thumbs up. After landing at Walter Reed just after 6:30 p.m., he entered his S.U.V. for the short drive from the landing site to the medical facility.
The president has a low-grade fever, nasal congestion and a cough, according to two people close to Mr. Trump. He was not planning to transfer his authority to Vice President Mike Pence, according to a White House spokesman, Judd Deere. “The president is in charge,” he said.
Mrs. Trump has reported mild symptoms.
The treatment the president received is an antibody cocktail developed by the biotech company Regeneron, according to the memo from his doctor, Sean P. Conley. Mr. Trump is also taking vitamin D, zinc, melatonin, a daily aspirin and famotidine (an antacid better known as Pepcid), the memo said.
Initial results suggest that Regeneron’s treatment can lower the level of the virus in the body when administered early in the course of an infection.
On Friday evening, Dr. Conley said in a brief statement that the president was “doing very well” and had started taking remdesivir, an experimental drug that has received emergency use approval from the Food and Drug Administration to treat hospitalized Covid-19 patients.
“He is not requiring any supplemental oxygen, but in consultation with specialists we have elected to initiate remdesivir therapy,” Dr. Conley said. “He has completed his first dose and is resting comfortably.”
Mr. Trump’s disclosure of his diagnosis came in a Twitter message just before 1 a.m., and followed reports that his close adviser Hope Hicks had tested positive.
His condition upended the presidential race in an instant, inviting significant questions about Mr. Trump’s cavalier attitude toward the pandemic and the future of his campaign just 32 days before the Nov. 3 election. Democrats wished Mr. Trump an easy recovery, but also criticized what they characterized as his reckless behavior.
Senate Democrats also demanded that Republicans slow the confirmation process for Judge Amy Coney Barrett to the Supreme Court, charging that “an already illegitimate process will become a dangerous one.”
Leading Republicans pledged to go “full steam ahead” to confirm Judge Barrett before Election Day. Judge Barrett, who met with Mr. Trump at the White House last weekend, tested negative on Friday.
Mr. Trump’s diagnosis also led to a flurry of tests for other people who had been near him in recent days, including many figures in Mr. Trump’s family and administration and prominent Fox News executives. Joseph R. Biden Jr., who faced Mr. Trump in an acrimonious debate on Tuesday, said that he had tested negative for the virus. At a campaign stop in Grand Rapids, Mich., Mr. Biden said that he and his wife, Jill Biden, hoped that Mr. and Mrs. Trump would have a full recovery.
“This is not a matter of politics, it’s a bracing reminder to all of us that we have to take this virus seriously,” Mr. Biden said.
Mr. Pence — the first in line to assume the president’s duties if Mr. Trump becomes too ill to do his job — tested negative for the virus on Friday, a glimmer of stability on a day when questions are swirling over what comes next should Mr. Trump’s symptoms worsen.
The presidential line of succession, laid out in a 1947 law, falls first to Mr. Pence. If he were to become too ill to carry out the duties of the president, the House speaker, Nancy Pelosi, would step in. Ms. Pelosi has been tested and is negative.
Mr. Trump has held increasingly crowded campaign events in recent weeks in defiance of public health guidelines and sometimes state and local governments.
On Thursday, Mr. Trump attended a fund-raiser at his golf club at Bedminster, N.J. One attendee there said the president came in contact with about 100 people, and seemed lethargic.
Hours before Mr. Trump announced his infection on Twitter, he told an audience that “the end of the pandemic is in sight.”
Gov. Philip D. Murphy of New Jersey urged people who attended Mr. Trump’s fund-raiser to get tested and said that the state was using contact tracing to try to find them.
Mr. Trump’s campaign announced Friday that it had postponed all in-person campaign events involving him or his family. He had planned to hold two rallies this weekend in Wisconsin, despite the fact that the White House coronavirus task force had placed the state in the “red zone” because of its high rate of infections and recommended maximum social distancing there.
Case numbers have been trending steadily downward recently in Washington, D.C. The city has averaged about 35 cases per day over the last week, about half as many as it did in mid August. Washington, D.C., was hit hard by the virus in the spring and has had more deaths per capita than all but seven states.
Bill Stepien, President Trump’s campaign manager, tested positive for the coronavirus on Friday, a person briefed on the matter said, making him the latest senior aide to the president to receive such a diagnosis in the past few days.
Mr. Stepien is experiencing mild symptoms and is in quarantine, the person said. His diagnosis was first reported by Politico, and confirmed to The Times.
Mr. Stepien was with Mr. Trump at the presidential debate in Cleveland on Tuesday, but it was unclear when he was last with the president. However, he was in closed-door preparation sessions with Mr. Trump and a half-dozen other aides and advisers on Saturday, Sunday, Monday and Tuesday. Mr. Trump and the first lady were confirmed by White House officials on Friday morning to have the virus.
Another aide who was in those preparation sessions, Hope Hicks, tested positive on Thursday. And Kellyanne Conway, the former senior White House aide who was also part of those sessions, said she tested positive Friday.
“Tonight I tested positive for COVID-19,” Ms. Conway said in a Twitter post. “My symptoms are mild (light cough) and I’m feeling fine. I have begun a quarantine process in consultation with physicians. As always, my heart is with everyone affected by this global pandemic.”
President Trump’s positive coronavirus test has raised questions about what the infection could mean for the health of the leader of the United States.
The president arrived at Walter Reed National Military Medical Center on Friday evening for what was expected to be a stay of a few days. His symptoms were described as a low-grade fever, nasal congestion and a cough, according to two people close to him.
Mr. Trump may experience worse symptoms because of his failure to wear a mask, according to an expert at the University of Pittsburgh.
Dr. David A. Nace, a geriatrics expert and director of medical affairs at the University of Pittsburgh Medical Center’s network of 35 nursing facilities, said in an interview on Friday that people who don’t wear masks are exposed to higher concentrations of the virus, which can worsen the course of the disease.
Here is what we know about how the virus could affect people fitting Mr. Trump’s profile.
Older men are at greater risk of becoming seriously sick.
Older men are up to two times as likely to die from Covid-19, the disease caused by the coronavirus, as women of the same age, according to an analysis by the Chinese Center for Disease Control and Prevention. Another study, published in the journal Nature in August, found that the disparity was because men produce a weaker immune response than do women.
Dr. Nace said that 5 to 15 percent of men in their mid-70s die from coronavirus, although Mr. Trump, who is 74, will obviously benefit from excellent medical care. And he said doctors know a lot more about how to treat Covid-19 now than they did early in the pandemic.
There are a few possible avenues of treatment.
“My big fear is that he probably had a greater exposure,” Dr. Nace said.
He said Mr. Trump might be eligible for the drug remdesivir or perhaps convalescent plasma, both of which have received emergency approval from the Food and Drug Administration for use as treatments. And he said doctors might also consider enrolling Mr. Trump in a clinical trial of monoclonal antibodies — laboratory-produced molecules that can stimulate the immune system, which does not mount as aggressive a response in people of Mr. Trump’s age.
The president has received a dose of an experimental antibody cocktail being developed by the drug maker Regeneron, in addition to zinc, vitamin D and the generic version of the heartburn treatment Pepcid, according to a letter from his doctor that was released by the White House on Friday afternoon.
One drug he would not give the president, Dr. Nace said, is hydroxychloroquine, which Mr. Trump touted as a “game changer” earlier in the pandemic. That drug can cause heart problems, Dr. Nace said, and in a disease like Covid-19, which can cause inflammation of the heart, “the risks are absolutely enormous.”
Many people Mr. Trump’s age have recovered.
Even though the risk of severe illness from Covid-19 increases with age, most people who contract it get well quickly with minimal symptoms.
But it’s hard to say how long a recovery could take.
Experts agree that the next week will be critical in determining the course of Mr. Trump’s illness.
President Trump has received a dose of an experimental antibody cocktail being developed by the drug maker Regeneron, in addition to several other drugs, including zinc, vitamin D and the generic version of the heartburn treatment Pepcid, according to a letter from his doctor that was released by the White House on Friday afternoon.
In the letter, Mr. Trump’s doctor, Dr. Sean P. Conley, said he “completed the infusion without incident” and that he “remains fatigued but in good spirits.”
There are no approved treatments for Covid-19, but the Regeneron treatment is one of the most promising candidates. Initial results have suggested that it can reduce the level of the virus in the body and possibly shorten hospital stays — when it is given early in the course of infection.
In an interview Friday afternoon, Regeneron’s chief executive, Dr. Leonard S. Schleifer, said Mr. Trump’s medical staff had reached out to the company for permission to use the drug, and that it was cleared with the Food and Drug Administration.
“All we can say is that they asked to be able to use it, and we were happy to oblige,” he said. He said that so-called compassionate use cases — when patients are granted access to an experimental treatment outside of a clinical trial — are decided on a case-by-case basis and that Mr. Trump is not the first patient to be granted permission to use the treatment this way. “When it’s the president of the United States, of course, that gets — obviously — gets our attention.”
Dr. Schleifer has known Mr. Trump casually for years, having been a member of his golf club in Westchester County.
In the 48 hours before President Trump tested positive for the coronavirus, he traveled to and from Ohio, Minnesota and New Jersey, all the while accompanied by his usual cadre of mostly mask-less staff and coming into contact with scores of supporters.
On Tuesday, Mr. Trump traveled to Cleveland, where he and his Democratic opponent, former Vice President Joseph R. Biden Jr., debated for the first time, standing six feet apart. For much of the 90 minutes, they shouted at and over each other. Mr. Biden tested negative for the virus on Friday, his staff said.
On the way back from the debate, Jared Kushner, the president’s senior adviser and son-in-law, could be seen in a staff cabin, speaking animatedly to his colleagues with no mask covering his face. Upon landing at Joint Base Andrews in the middle of a heavy rainstorm, others on Air Force One huddled together to share an umbrella.
On Wednesday, Mr. Trump and his team traveled to Minnesota for a rally, which lasted about 45 minutes, roughly half the length of one of his typical rally speeches. During the campaign event, one of Mr. Trump’s closest advisers, Hope Hicks, started to have symptoms common of the virus and later tested positive.
On the way back, a person briefed on the matter said that Mr. Trump fell asleep at one point on Air Force One, as some of his advisers spoke about Ms. Hicks’s symptoms while she was isolated in the back of the plane.
By Thursday, it was clear that something unusual was happening at the White House, aides said. Several staff members who have avoided masks were suddenly wearing them.
News of Ms. Hicks testing positive came on Thursday, as Mr. Trump left the White House by helicopter around 1 p.m. headed to a fund-raiser in New Jersey, where he appeared before hundreds of supporters at his golf club in Bedminster, both outside and indoors. One person who saw Mr. Trump there said he came in contact with about 100 people and appeared lethargic.
On a call with Iowa voters and in an interview later with Sean Hannity on Fox News, Mr. Trump sounded raspy. Some aides chalked it up to a busy week of campaigning.
On Thursday evening, in a taped address to an annual charity dinner, Mr. Trump said, “the end of the pandemic is in sight.”
Mr. Trump confirmed the news of Ms. Hicks’s result while on Sean Hannity’s show on Fox News on Thursday and said he was awaiting his own test. His dramatic disclosure that he and the first lady had tested positive came in a Twitter message just before 1 a.m. after a suspenseful evening following reports about Ms. Hicks.
By Friday morning, the president was showing mild symptoms of Covid-19, the disease caused by the novel coronavirus, according to Mark Meadows, the White House chief of staff.
The first lady, Melania Trump, said she has mild symptoms, “but overall feeling good.”
The president’s diagnosis did not appear to have significantly changed the behavior of some of his closest advisers, who were walking around the White House complex without masks on Friday morning.
Gov. Philip D. Murphy of New Jersey on Friday urged people who attended Mr. Trump’s Bedminster fund-raiser to get tested and said that the state was using contact tracing to find them.
“As far as we know, folks are cooperating,” Mr. Murphy said.
Increasingly, it looks as if a possible source of the spread may have been the ceremony in the White House Rose Garden last Saturday at which Mr. Trump announced his nomination of Judge Amy Coney Barrett for the Supreme Court, an event where few wore masks or maintained social distance. So far, several people who were there have said they have since tested positive, including Senator Mike Lee, Republican of Utah; Senator Thom Tillis, Republican of North Carolina; Melania Trump, the first lady; Kellyanne Conway, the former top White House adviser; and the Rev. John I. Jenkins, the president of the University of Notre Dame. (An earlier version of this article also included Michael D. Shear, a White House correspondent for The New York Times who has tested positive; Mr. Shear was at the White House on Saturday but did not attend the Rose Garden event.)
Joseph R. Biden Jr., the Democratic presidential nominee, tested negative for the coronavirus on Friday, his campaign announced, and he later traveled to Michigan for an event there.
“We wanted to make sure that we’re doing everything by the numbers,” a masked Mr. Biden said in Grand Rapids, adding that “everything is clear.”
Mr. Biden sent his prayers to President Trump and the first lady, Melania Trump. “This is not a matter of politics,” he said. “It’s a bracing reminder to all of us that we have to take this virus seriously. It’s not going away automatically. We have to do our part to be responsible.”
Earlier in the day, just hours after Mr. Trump revealed he had tested positive, Mr. Biden’s campaign released a statement from his doctor saying that Mr. Biden and his wife, Jill Biden, had both tested negative. Mr. Biden also shared the news on Twitter.
“Thank you to everyone for your messages of concern,” he wrote. “I hope this serves as a reminder: wear a mask, keep social distance, and wash your hands.”
While Mr. Biden went ahead with his trip to Michigan, his wife, Dr. Biden, campaigned in New Hampshire, and she was scheduled to make several stops in Minnesota on Saturday.
Mr. Biden appeared on the debate stage with Mr. Trump on Tuesday night. Eleven coronavirus cases have been tied to “pre-debate planning and setup,” according to a statement from the Cleveland mayor’s office, and “the majority of cases” affected out-of-state residents.
It can take several days after exposure for the virus to reach levels that are detectable by a test. People show symptoms on average around five days after exposure, but as late as 14 days.
Mr. Biden’s running mate, Senator Kamala Harris of California, and her husband, Douglas Emhoff, also tested negative on Friday, the campaign said. Ms. Harris and Mr. Emhoff continued with planned campaign trips to Nevada and North Carolina, respectively. A virtual fund-raiser with Ms. Harris and former President Barack Obama also went ahead.
“This virus is still very much active across our country, please continue to wear a mask and maintain social distancing,” Ms. Harris wrote on Twitter.
Vice President Mike Pence — the first in line to assume the Oval Office if President Trump becomes too ill to carry out his duties — tested negative for the virus on Friday.
Mr. Trump was taken to Walter Reed National Military Medical Center on Friday night. A White House spokesman said there were no plans to transfer the power of the presidency to Mr. Pence.
The administration and the Trump campaign also said Friday that Mr. Pence “does not need to quarantine” and would resume campaign appearances, including at the vice-presidential debate against Senator Kamala Harris on Wednesday night.
Jesse T. Schonau, Mr. Pence’s White House physician, said that the vice president “remains in good health and is free to go about his normal activities.”
Mr. Pence, who has been campaigning separately from the president on Air Force Two, was last with him on Tuesday morning in Washington.
Mr. Pence spent the day at his official residence at the Naval Observatory miles away from the White House, preparing for the debate, which is supposed to proceed as planned at the University of Utah, and filling in for Mr. Trump on a conference call.
“I’m pleased to report President Trump and the first lady are both well at this time,” said the vice president. “They will remain at the White House while they convalesce.”
By evening, Mr. Trump had departed for Walter Reed.
The government’s continuity plan in case of a national emergency outlines who would take over if Mr. Trump became too ill to carry out his duties.
The presidential line of succession, laid out in a 1947 law, falls first to Mr. Pence. After years of speculation that the vice president might succeed Mr. Trump after potential resignation or removal from office, Mr. Pence now finds the possibility of assuming presidential duties more plausible than ever, if his health holds up.
Like the president, Mr. Pence has not always taken stringent precautions against the coronavirus. He has been photographed in public regularly without a mask, even after his press secretary, Katie Miller, tested positive in May.
Mr. Pence was criticized in April for not wearing a mask while touring the Mayo Clinic. He defended his behavior by saying that he did not need to wear a mask because he was tested regularly.
Should Mr. Pence’s health fail, the House speaker, Nancy Pelosi, would be next to step in. Ms. Pelosi tested negative, Drew Hammill, a spokesman, said Friday afternoon.
After Ms. Pelosi, Senator Chuck Grassley, the president pro tem, would take up the mantle. Next in line is the secretary of state, Mike Pompeo, and after him is the Treasury secretary, Steven Mnuchin. (An earlier version of this article omitted the president pro tem.)
Not since 1981, when Ronald Reagan was shot, has a president been known to confront a life-threatening ailment in office.
President Trump’s bombshell announcement early Friday morning that he and the first lady had tested positive for the coronavirus has set off a frenzy in the White House and beyond as politicians and operatives who have interacted with Mr. Trump in recent days have raced to get their own tests and, in some cases, report the results.
Here is a quick look at the people in Mr. Trump’s orbit and beyond who have spoken publicly within the last several hours about their health and the virus, according to official statements, announcements made on social media, and spokespeople.
It can take several days after exposure for the virus to reach levels that are detectable by a test. People show symptoms on average around five days after exposure, but as late as 14 days.
Who has tested positive:
Who has tested negative:
Mike Pompeo, the secretary of state
Steven Mnuchin, the Treasury secretary
William P. Barr, the attorney general
Mark Meadows, the White House chief of staff
Dan Scavino, the White House deputy chief of staff
Jared Kushner, Mr. Trump’s son-in-law and senior adviser
Ivanka Trump, Mr. Trump’s daughter
Barron Trump, Mr. Trump’s son
Eric Trump, Mr. Trump’s son
Lara Trump, Eric Trump’s wife
Tom Perez, the chairman of the Democratic National Committee
Betsy DeVos, the education secretary
For months, the White House’s strategy for keeping President Trump and his inner circle safe has been to screen all White House visitors with a rapid test.
But the product they use, Abbott’s ID Now, was never intended for that purpose and is known to deliver incorrect results. In issuing an emergency use authorization, the Food and Drug Administration said the test was to be used only by a health care provider “within the first seven days of symptoms.”
The ID Now has several qualities in its favor: It’s portable, doesn’t need skilled technicians to operate and delivers results in 15 minutes. Used to evaluate someone with symptoms, the test can quickly and easily diagnose Covid-19, the disease caused by the coronavirus.
In people who are infected but not yet showing symptoms, however, the test is much less accurate, missing as many as one in three cases.
In May, after many reports of problems with the test, the F.D.A. warned that those who test negative using the test should confirm that result with a lab-based test.
Still, the Trump administration has routinely used the test to screen people without symptoms, allowing anyone who tested negative to go without a mask during meetings and official proceedings.
The Rev. John I. Jenkins, president of the University of Notre Dame, tested positive for the coronavirus after attending the White House announcement of the Supreme Court nominee, Judge Amy Coney Barrett, on Saturday. He apologized for going mask-free at the ceremony but said he was told he could do so after his rapid test came back with a negative result.
Given the timing of Mr. Trump’s illness, experts said it is quite possible that he was exposed to the virus on Saturday.
On Saturday, President Trump met with Judge Amy Coney Barrett, the nominee to the Supreme Court, and others in the Oval Office. On Tuesday, he debated former Vice President Joseph R. Biden Jr. in an indoor hall, neither with a mask, talking at high volume and often without pause.
On Wednesday, Mr. Trump traveled to and from Minnesota on Air Force One along with dozens of others. On Thursday, the president appeared indoors before hundreds of supporters at a golf club in Bedminster, N.J.
On none of these occasions was the president wearing a mask. Often, neither were many in the room or on the airplane with him. All in all, conditions like these are a recipe for so-called superspreader events, in which a single infected person transmits the virus to dozens of others, research has shown.
Experts may never know how the president was infected or whom he may have infected. The Rev. John I. Jenkins, president of the University of Notre Dame, tested positive for the coronavirus after attending a White House ceremony on Saturday for Judge Barrett. So did Senator Mike Lee, Republican of Utah.
The timing raises the possibility that the president could have been infected over the weekend, scientists said. Most people develop symptoms about five days after being infected with the virus, so exposure over the weekend would fit with reports that the president was showing early symptoms on Wednesday and Thursday.
The University of Notre Dame announced on Friday that its president, the Rev. John I. Jenkins, had tested positive for the coronavirus, just days after he had publicly apologized for not wearing a mask or adhering to social distancing guidelines while at a White House ceremony over the weekend.
“The positive test is a good reminder for me and perhaps for all of how vigilant we need to be,” Father Jenkins said in an email to Notre Dame students and staff. He also said that his symptoms were mild.
The message sent by the university’s public affairs office to the Notre Dame community said Father Jenkins was “entering an extended period of isolation as indicated by University medical personnel and county health officials.”
Father Jenkins had not worn a mask during the Supreme Court nomination ceremony on Saturday at the White House for Judge Amy Coney Barrett, who is a professor at Notre Dame, an event that increasingly looked like a possible source of spread.
Father Jenkins said he was given a rapid coronavirus test upon arriving at the White House and was told that it would be safe to remove his mask after receiving negative results. Many other unmasked officials attended the ceremony, including Senator Mike Lee, Republican of Utah, who announced on Friday that he, too, had tested positive for the coronavirus. Video posted on Twitter shows Mr. Lee hugging people at the event. He said he had tested negative at the White House on Saturday.
Others in attendance included Alex M. Azar II, the health secretary; Chris Christie, the former governor of New Jersey and an adviser to the president; and Attorney General William P. Barr. All three said they had tested negative, but it can take several days after exposure for the virus to reach levels that are detectable by a test. People show symptoms on average around five days after exposure, but as late as 14 days.
Judge Barrett, 48, also tested negative on Friday, White House officials said.
Notre Dame said that Father Jenkins, who is also a philosopher trained in theology and a member of Notre Dame’s philosophy department, had tested positive after he “learned that a colleague with whom he has been in regular contact tested positive for Covid-19.”
Just weeks ago, Father Jenkins was chiding students and threatening to send them home for failing to abide by mask and distancing rules and putting the university in danger. He apologized for not following such guidance himself on Monday, and said that he had decided to quarantine “in an abundance of caution” after returning to the campus from the White House.
Speaker Nancy Pelosi of California expressed fresh optimism on Friday that a bipartisan deal for a broad coronavirus package could emerge out of her talks with Treasury Secretary Steven Mnuchin, floating the possibility that President Trump’s positive test for the coronavirus could change the tenor of the negotiations.
“This kind of changes the dynamic, because here they see the reality of what we have been saying all along: This is a vicious virus,” Ms. Pelosi said on MSNBC.
Her comments came the morning after Democrats muscled their latest, $2.2 trillion offer for a relief package through the House over unanimous Republican opposition, endorsing a wish list with little chance of enactment in a signal of the grim outlook for an agreement that could become law.
Ms. Pelosi and Mr. Mnuchin spoke by phone Friday afternoon for about 65 minutes, during which “they discussed areas of disagreement,” said Drew Hammill, a spokesman for Ms. Pelosi. “Their discussions will continue.”
Ms. Pelosi was bullish on the talks earlier on Friday, insisting that she and Mr. Mnuchin would “find our common ground.”
“We’re legislators,” she said. “We’ll get the job done.”
Republicans have balked at Democrats’ relief plans, deeming them far too costly, but Mr. Trump’s diagnosis, coming on the heels of a grim jobs report, had the potential to change their political calculations, possibly jolting the White House and leading Republicans into a more compromising posture as they face strong political headwinds.
Some members of Congress also began calling for more widespread testing of lawmakers and their staff members after Mr. Trump and Senator Mike Lee of Utah tested positive. As members left Washington to return to their districts they expressed concern about spreading the virus.
“I really do think that there’s a strong possibility that every time we convene in a session, it has the potential to be a superspreader event,” said Representative Alexandria Ocasio-Cortez, Democrat of New York. “We’re talking about 425 members of Congress coming from all over the country flying on planes coming here.”
Representative Rodney Davis of Illinois, the highest-ranking Republican on the House Administration committee, called it a “travesty that we don’t have a testing modality system in place.”
The House is not expected to be in session next week, despite concerns from moderate lawmakers about returning home to their districts ahead of Election Day without a stimulus deal in place.
“It’s very disappointing,” said Representative Anthony G. Brown, Democrat of Maryland. “I’ve got constituents — you know, I’m right down the road in Prince George’s County, Maryland, and Anne Arundel, Maryland — whose businesses are shuttered, who have been furloughed for far too long. They need help.”
Mr. Mnuchin presented Ms. Pelosi earlier this week with a $1.6 trillion counteroffer, the largest put forward by Republicans in months, but one that Ms. Pelosi rejected as inadequate.
Alex M. Azar II, the secretary of health and human services, defended members of President Trump’s family on Friday for refusing to wear masks at the recent presidential debate despite a requirement that the audience do so. The first family and the president are “in a different situation than the rest of us,” Mr. Azar said, because they are in a protective bubble.
The first lady, Melania Trump, who was in the audience and has since tested positive, was among those who did not wear a mask.
Mr. Azar’s comments came during a hearing of a special House committee overseeing the administration’s coronavirus response, where the secretary repeatedly ducked questions about the president’s conduct.
Pushed by Representative Maxine Waters, Democrat of California, he pointedly did not defend Mr. Trump’s campaign rallies. Instead he repeated his encouragement for Americans to wear masks and maintain social distancing.
When Democrats urged the health secretary to acknowledge that the president’s own failure to wear masks set a bad example for the nation, Mr. Azar simply reiterated that his advice was for everyone to do so. Yet even as he spoke, the president’s science adviser, Dr. Scott Atlas, was seen outside the West Wing without a mask.
One of the most withering attacks of the hearing came from Ms. Waters, whose sister died of Covid-19.
“Are you proud of the job you have done?” she demanded.
“I don’t like to speak in those terms; 206,000 people have died,” Mr. Azar replied.
Earlier in the hearing, he was asked about a remark the president made about the pandemic’s toll, “It is what it is.”
“We regret any loss of life,” Mr. Azar said. “Let’s be very clear about that. We wish we didn’t have this unprecedented coronavirus pandemic, but people do die in pandemics.”
President Trump’s disclosure that he had been infected by the coronavirus sent a shudder around the world on Friday, shaking global markets and drawing sympathy from leaders who have grappled with the pandemic in their own countries and more pointed responses from critics who noted Mr. Trump’s own cavalier handling of the threat.
Mr. Trump is not the first world leader to be infected. Prime Minister Boris Johnson of Britain and President Jair Bolsonaro of Brazil both tested positive. And Mr. Johnson suffered a serious bout of Covid-19, ending up in an intensive care unit where, he said later, “things could have gone either way.”
But Mr. Trump, 74, is older and at higher risk than either of those men. The news of an American president contracting a potentially lethal virus carried global repercussions beyond that of any other world leader.
Global markets dropped Friday after Mr. Trump disclosed that he and his wife have the virus, throwing into doubt the political leadership of the world’s largest economy.
Financial markets fell in Asia, and European markets opened more than 1 percent lower with some markets recovering slightly as the day went on. The S&P 500 was volatile, falling as much as 1.7 percent in early trading before closing down 0.7 percent. The Dow Jones industrial average fell 0.48 percent to close at 27,682.81. Investments that are more sensitive to economic and policy shifts fell quickly. Oil futures slid on Friday along with other commodities.
Expressions of concern and good wishes for Mr. Trump’s speedy recovery — as well as that of the first lady, Melania Trump — poured in from leaders in Britain, India, Russia and other countries.
Some foreign commentators, however, took note of Mr. Trump’s handling of the pandemic, saying his illness was a reminder of a virus that drew no distinctions between rich or poor, powerful or weak.
Others suggested a degree of justice in his diagnosis, given his record of diminishing the threat of the virus, refusing simple precautions like wearing a face mask and holding campaign rallies without social distancing.
“When the president of the United States, the most powerful person in the world, can catch this, the virus has no boundaries,” said Wang Huiyao, the founder and president of the Center for China and Globalization, an influential research group in Beijing.
A son of Rupert Murdoch and some of the biggest stars at Fox News were potentially exposed to the coronavirus while attending Tuesday’s presidential debate in Cleveland, and the network is planning for its anchors, reporters and staff to be tested out of an abundance of caution, according to a person familiar with its plans.
Chris Wallace, the Fox News anchor who sat within 12 feet of President Trump while moderating the debate, had some stark advice for his network’s viewers: “Wear the damn mask.”
“Follow the science,” Mr. Wallace said, appearing Friday on “Fox & Friends” and other Fox News programs. “If I could say one thing to all of the people out there watching: forget the politics. This is a public safety health issue.”
The anchor said he planned to take a coronavirus test on Monday on the advice of his doctors, who said that any infection could take several days to generate a positive result.
Lachlan Murdoch, executive chairman of the Fox Corporation, led a toast to Mr. Wallace at a Cleveland airport after the event. The gathering included two of the channel’s news anchors, Bret Baier and Martha MacCallum, along with the Fox News chief executive, Suzanne Scott, and the president of Fox News Media, Jay Wallace.
Mr. Wallace then flew on a private plane to the Washington area in a group that included Mr. Baier and other Washington-based members of the Fox News staff.
Several Fox News opinion hosts have accused much of the national news media of overstating the dangers of the virus. One frequent Fox News guest who played down the risks, Dr. Scott Atlas, has since become a top pandemic adviser to the president.
On Friday, Mr. Wallace was unequivocal in warning against Dr. Atlas’s advice — even as his colleague, the Fox News anchor Sandra Smith, teased an exclusive interview with Dr. Atlas in which the doctor said he expected Mr. Trump would make a full recovery and return to the campaign trail.
“I’m going to say something and, folks, I’m just trying to give you the truth,” Mr. Wallace said. “Dr. Scott Atlas is not an epidemiologist, is not an infectious disease expert — he has no training in this area at all. There are a number of top people on the president’s coronavirus task force who have had grave concerns about Scott Atlas and his scientific bona fides.”
Recounting his experience at Tuesday’s debate, Mr. Wallace told viewers that members of Mr. Trump’s family had removed their masks after entering the debate hall in violation of the rules of the Cleveland Clinic, which had been contracted to oversee the health and safety protocols for the event. “A health person from the Cleveland Clinic came up to the first family when they were seated and offered them masks in case they didn’t have them, and they were waved away,” the anchor recalled.
President Trump has joined the ranks of world leaders who have tested positive for the coronavirus. Here is a look at some of the others:
Britain: Prime Minister Boris Johnson, 56
Mr. Johnson, who in the early part of the pandemic resisted a lockdown and social-distancing measures, contracted the virus in March. He was later hospitalized and deputized the country’s foreign secretary, Dominic Raab, to carry out his duties. After Mr. Johnson was released from the hospital in April, he thanked Britain’s National Health Service, saying that it had “saved my life, no question.”
It is hard to find the words to express my debt to the NHS for saving my life.
The efforts of millions of people across this country to stay home are worth it. Together we will overcome this challenge, as we have overcome so many challenges in the past. #StayHomeSaveLives pic.twitter.com/HK7Ch8BMB5
— Boris Johnson (@BorisJohnson) April 12, 2020
Brazil: President Jair Bolsonaro, 65
Like Mr. Trump, Mr. Bolsonaro was cavalier about the disease, calling it a “measly cold.” Even as his country became one of the hardest-hit by the pandemic, he attended political rallies, shook hands with supporters and went around without a face mask. To date, more than 144,000 Brazilians have died from the virus. He said in July that he had contracted the virus, although his case appeared to have been mild.
Honduras: President Juan Orlando Hernández, 51
Mr. Hernández tested positive in June along with his wife and two aides, and was treated for pneumonia. He initially vowed to keep working as he displayed mild symptoms, but his health quickly worsened, and for days Mr. Hernández remained in a “delicate” situation, doctors said, as he was hospitalized and needed oxygen.
Bolivia: President Jeanine Añez, 53
Ms. Añez, Bolivia’s caretaker leader who took office in January after the ouster of former President Evo Morales, tested positive for the virus in July. She remained in self-isolation for 14 days.
Guatemala: President Alejandro Giammattei, 64
Mr. Giammattei announced last month that he had tested positive, on the day that the Central American country reopened its borders and international flights after a six-month closure.
Armenia: Nikol Pashinyan, 45
Mr. Pashinyan went into self-isolation in June after he and his close family tested positive. A week later, after displaying no symptoms, Mr. Pashinyan said he had tested negative.
The Michigan Supreme Court on Friday struck down Gov. Gretchen Whitmer’s executive orders issued over several months that were aimed at slowing the spread of the coronavirus.
In a 4-3 decision, the court ruled that she illegally drew authority from a 1945 law called the Emergency Powers of Governor Act that did not apply to the pandemic.
“The governor did not have authority after April 30, 2020, to issue or renew any executive orders related to the Covid-19 pandemic,” the court wrote.
Just hours before the decision was handed down, Governor Whitmer, a Democrat, had issued a fresh executive order rolling back the reopening of the state’s Upper Peninsula. The order restricts retail capacity, the size of social gatherings and requires schools to enforce mask requirements.
That order drew authority in part from the 1945 law the court said does not apply. It was not immediately clear if the new order was enforceable.
“Today’s Supreme Court ruling, handed down by a narrow majority of Republican justices, is deeply disappointing, and I vehemently disagree with the court’s interpretation of the Michigan Constitution,” Governor Whitmer said in a statement on Friday evening, adding that the ruling would not take effect for at least 21 days and that the existing orders would “retain the force of law” until then.
Michigan officials reported 993 new cases and seven new deaths on Friday. There have been at least 140,057 cases and 7,110 deaths in the state since the beginning of the pandemic, according to a New York Times database.
The Secret Service sustained a coronavirus outbreak at its training facility in Maryland in August, weeks before President Trump was infected, evidence of growing infections at the agency responsible for protecting the president.
At least 11 employees at the center in rural Maryland tested positive for the virus even after it was closed for several months to mitigate transmissions, according to officials briefed on the matter.
Some of the personnel are believed to have contracted the virus during training exercises or at a graduation celebration at a nearby hotel where participants did not practice social distancing, the people said.
The agency declined to discuss the specifics of the outbreak, but it said in a statement that it “has taken significant precautions at its training center to protect the health and welfare of its trainees and training staff.” There is no indication that this outbreak led to infections among the agents and officers who directly protect the president.
The details about the problem at the center were uncovered by the Project on Government Oversight, an independent watchdog group in Washington. The organization brought the information about the outbreak to The New York Times, which independently confirmed details of it with people briefed on the matter. Those people spoke on the condition of anonymity because they did not want to be identified discussing delicate personnel matters.
The news early Friday morning that the president and the first lady had tested positive for the coronavirus gave the Secret Service outbreak new relevance. Hours before that announcement, the White House confirmed that Hope Hicks, a close adviser to Mr. Trump, had been infected.
President Trump’s recent suggestion that the White House may not approve stricter criteria for the emergency authorization of any coronavirus vaccine is causing growing angst in the biotech industry, whose trade organization is calling on the Department of Health and Human Services to quickly publish the guidelines and make them available to the public.
The new guidelines, drafted by experts at the Food and Drug Administration and subject to White House approval, would set forth specific criteria for clinical trial and safety data, adding another layer of caution to the vetting process. The F.D.A. appeared poised to release them, but the process seems to have stalled since Mr. Trump said last month that the White House “may or may not” approve the new stricter criteria.
Now industry officials are worried that the guidelines, which they believe will restore confidence in the vaccine approval process, may never be released.
“We cannot allow a lack of transparency to undermine confidence in the vaccine development process,” Michelle McMurry-Heath, the president and chief executive of the trade group BIO, wrote in a letter sent Thursday evening to Mr. Trump’s health secretary, Alex M. Azar II. “The public must have full faith in the scientific process and the rigor of F.D.A.’s regulatory oversight if we are to end the pandemic.”
BIO’s members include many of the major pharmaceutical companies, including all of the coronavirus vaccine makers except AstraZeneca.
In an interview, Dr. McMurry-Heath, who is also a former F.D.A. official, said that she and her members were “deeply concerned” about the delay, adding, “I know the incredible dedication of the F.D.A. staff, but I also know how important it is not to politicize the process. And any sign that the White House — any White House — is interfering in the process will simply erode public confidence.”
There are currently more than 180 coronavirus vaccines in development and nine are either late in the second stage or in the third and final stage of clinical trials. Dr. McMurry-Heath said vaccine makers were concerned that “the political jockeying around the F.D.A.” could lead states to impose their own safety criteria, adding an extra layer of bureaucracy that could delay distribution. In New York, Gov. Andrew M. Cuomo has already said his state would do so.
The Pentagon said on Friday morning that there had been no changes to alert levels for American troops worldwide, and that military analysts had not detected any unusual activity from potential adversaries resulting from the announcement that President Trump had tested positive for the coronavirus.
“There’s been no change to our alert levels,” the military’s Joint Staff said in a statement. “The U.S. military stands ready to defend our country and its citizens. There’s no change to the readiness or capability of our armed forces.”
General Mark Milley, the chairman of the Joint Chiefs of Staff, and Defense Secretary Mark Esper were last with Mr. Trump on Sunday, an administration official said, at a reception for Gold Star families attended by both Mr. Trump and the first lady, Melania Trump. They are both getting tested, the official said. Mr. Esper was traveling in North Africa on Friday, while General Milley was at the Pentagon.
As commander in chief, Mr. Trump can readily use secure communications channels to confer with top civilian Pentagon officials and military commanders while in quarantine at the White House, military officials said.
Military officials tracking operations in the Middle East, Europe, Africa and the Pacific said they were monitoring for any possible increase in threats, but as of Friday morning had not detected any unusual activity.
Football is grappling with a scourge of overt, if not always deliberate, violations of mask mandates among coaches and players.
The N.F.L. has angrily watched some of its biggest names defy its rules. Most coaches in the Southeastern Conference, home to some of the best college teams, repeatedly breached the league’s policy during opening weekend, and college conferences are weighing how to police their stated protocols.
The question is not easily solved in a sport that has long been politicized, that prizes its image as a haven for the macho and that sometimes lacks centralized governance.
The N.F.L., which this week postponed the Steelers-Titans game because of an outbreak, has handed down at least $1.7 million in fines, and a top league executive warned coaches that penalties could escalate to suspensions or a loss of draft picks.
There has been less urgency in the college ranks, where no coach or player has been publicly disciplined for violating masking policies.
Although critics of mask rules have correctly noted that most games are outdoors and that players and coaches are regularly tested for the virus, officials believe that the coverings can still help curb the pathogen’s spread. Regular testing has detected outbreaks, but has not left teams immune to them.
And the conspicuous breaches have revived questions about how closely athletic programs nationwide are following health rules.
A recent survey of more than 1,200 college athletic trainers found that just 47 percent of coaches and staff members across sports were “fully compliant” with safety protocols related to the virus. The survey, conducted by the National Athletic Trainers’ Association, also found that roughly 7 percent of coaches and staff members did not follow the rules at all.
President Vladimir V. Putin of Russia sent President Trump a telegram wishing him and the first lady, Melania Trump, “a speedy recovery and expressing sincere support at this difficult moment,” the Kremlin said Friday.
“I am sure that your inherent vitality, vigor and optimism will help you overcome the dangerous virus,” Mr. Putin wrote to Mr. Trump, according to the Kremlin.
Mr. Putin and his government have largely declared victory over the virus in recent months, and allowed life in Russia mostly to return to normal.
But unlike Mr. Trump, Mr. Putin has gone to extraordinary lengths to protect himself from the virus: the few people who see the Russian president in person are generally required to quarantine for as much as two weeks first.