President Trump’s vital signs were “very concerning” over the last day and he is not out of danger, the White House chief of staff said on Saturday, contradicting a rosier picture painted by the president’s doctors on television just minutes before.
And in a four-minute video posted to Twitter on Saturday evening, Mr. Trump said he was “starting to feel good,” but added that the severity of his case would probably become apparent over the coming days. The video, meant to reassure the nation, showed him sitting at a conference table at the hospital and wearing a suit jacket but no tie.
“You don’t know, over the next period of a few days, I guess that’s the real test,” he said. “So we’ll be seeing what happens over those next couple of days.”
Mr. Trump said he “wasn’t feeling so well” when he arrived at Walter Reed National Military Medical Center, but said “I feel much better now” and that he expected to return to work shortly.
The White House physician, Dr. Sean P. Conley, said later Saturday night that the president had made “substantial progress since diagnosis.” Mr. Trump was “fever-free and off supplemental oxygen,” Dr. Conley said after he had declined earlier on Saturday to say whether the president had been on oxygen at any point since being diagnosed with Covid-19.
“While not yet out of the woods,” Dr. Conley said, “the team remains cautiously optimistic.”
While the president’s doctors had maintained earlier Saturday that Mr. Trump was “doing very well” and in “exceptionally good spirits” after his first night in the hospital with the coronavirus, Mark Meadows, the chief of staff, provided a more sober assessment and warned that the next two days would be pivotal in determining the outcome of the illness.
“The president’s vitals over the last 24 hours were very concerning and the next 48 hours will be critical in terms of his care,” Mr. Meadows told reporters outside Walter Reed, where the president was flown on Friday evening and will remain for at least a few days. “We’re still not on a clear path to a full recovery.”
Mr. Meadows’s remarks were attributed to a person familiar with the president’s health in a pool report sent to White House journalists in keeping with ground rules that he set for the interview. But a video posted online captured Mr. Meadows approaching the pool reporters outside Walter Reed following the doctors’ televised briefing and asking to speak off the record, making clear who the unnamed source was.
The comments infuriated the president, according to people close to the situation, and he intervened directly to counter the perception that he was sicker than the White House has admitted. Within hours, he posted a message on Twitter saying “I am feeling well!” and called his friend and personal lawyer Rudolph W. Giuliani to have him convey a message to the outside world. “I’m going to beat this,” Mr. Trump told him.
Mr. Meadows called into Fox News on Saturday night, knowing the president was most likely watching, and praised his “unbelievable courage” and “unbelievable improvement.” But he also confirmed that Mr. Trump’s condition on Friday was worse than originally described. “Yesterday morning we were real concerned with that,” Mr. Meadows said. “He had a fever and his blood oxygen level had dropped rapidly.”
The mixed messages only exacerbated the confusion and uncertainties surrounding the president’s situation. During their briefing on Saturday, the doctors refused to provide important details and gave timelines that conflicted with earlier White House accounts and left the impression that the president was sick and began treatment earlier than officially reported.
Two people close to the White House said in separate interviews with The New York Times that the president had trouble breathing on Friday and that his oxygen level dropped, prompting his doctors to give him supplemental oxygen while at the White House and transfer him to Walter Reed where he could be monitored with better equipment and treated more rapidly in case of trouble.
During the televised briefing, Dr. Conley said the president was not currently receiving supplemental oxygen on Saturday but repeatedly declined to say definitively whether he had ever been on oxygen. “None at this moment and yesterday with the team, while we were all here, he was not on oxygen,” he said, seeming to suggest that there was a period on Friday at the White House when he was.
Dr. Conley likewise appeared to indicate that the president was first diagnosed with the virus on Wednesday rather than Thursday night, before Mr. Trump disclosed the test on Twitter early Friday morning. While describing what he said was the president’s progress, he said Mr. Trump was “just 72 hours into the diagnosis now,” which would mean midday on Wednesday.
Just two hours later, the White House issued a statement it said was written by Dr. Conley trying to clarify. “This morning while summarizing the president’s health, I incorrectly used the term ‘72 hours’ instead of ‘Day 3,’” it said.
Dr. Conley also said that on Thursday afternoon “we repeated testing and, given clinical indications, had a little bit more concern.” Late that night, he said, “we got the P.C.R. confirmation that he was” positive. Mr. Trump attended campaign events on both Wednesday night and Thursday without wearing a mask and gathering hundreds of supporters who likewise were not taking precautions against the virus.
Dr. Brian Garibaldi, another physician treating the president, also said that Mr. Trump had received an experimental antibody therapy “about 48 hours ago,” which would have been midday Thursday — before the confirmation test Dr. Conley said came back positive that evening and a full day before the White House disclosed the treatment on Friday.
The confusion came from a briefing where Dr. Conley and his team offered a relentlessly positive assessment of Mr. Trump’s condition. “This morning the president is doing very well,” Dr. Conley said. “At this time, the team and I are extremely happy with the progress the president has made.”
The doctors said Mr. Trump had been free of fever for 24 hours and had blood pressure and heart rates that were normal for him. Asked why he moved Mr. Trump to the hospital, Dr. Conley said, “Because he’s the president of the United States.”
Dr. Sean N. Dooley, another physician on the team, said Mr. Trump was feeling optimistic. “He’s in exceptionally good spirits,” Dr. Dooley said. He added that the president told his doctors, “I feel like I could walk out of here today.”
In his rambling video statement, Mr. Trump looked wan and sounded less energetic than usual. At one point, he offered a muddled explanation for his behavior that was not entirely clear whether he was talking about his decision to go to the hospital or to keep campaigning in recent months despite the pandemic. “I had no choice,” he said. “I just didn’t want to stay in the White House.” He added: “I can’t be locked up in a room upstairs and totally safe and just say, hey, whatever happens, happens. I can’t do that. We have to confront problems.”
President Trump will stay at the Walter Reed military hospital for an indefinite number of days, his doctor said on Saturday, undergoing a five-day antiviral drug regimen for Covid-19 that indicated his condition might be more serious than had been publicly disclosed.
On Thursday, he received another therapy that is still in early phases of testing.
Medical experts who have been following the sketchy, conflicting details released by the White House and Walter Reed about the president’s condition were divided about the experimental treatments Mr. Trump, 74, has already received.
But they generally welcomed his close monitoring at the nation’s military medical complex, noting his risk factors — that he’s an older man who is slightly obese — for developing a more serious form of the disease.
“This is a nightmare,” said Dr. Jeremy Faust, an emergency medicine physician at Brigham and Women’s Hospital in Boston. “When we first learned about this disease, it was the patients who fit the president’s description who we were most worried about.”
One of the therapies being given to Mr. Trump, a cocktail of monoclonal antibodies made by the biotech company Regeneron, is in the earliest phase of testing and there is only a recent news release from the company on its effectiveness.
Some experts are optimistic that the Regeneron drug works, and support giving patients a therapy that directly attacks the virus. Monoclonal antibodies in general are pretty safe, experts said, and similar ones have been used to treat patients with H.I.V. and Ebola.
Other experts were skeptical.
“In my mind these antibodies are experimental,” said Dr. Andre Kalil, an infectious disease specialist at the University of Nebraska, and a principal investigator for the federal study showing that remdesivir — the other treatment that is being given to Mr. Trump — sped recovery in hospitalized Covid patients.
“I don’t know how safe they are for the president,” Dr. Kalil said. “They should not be given outside of a clinical trial.”
Remdesivir is the standard of care now for some Covid patients, so some participants in a Regeneron trial of hospitalized Covid patients are likely to have received both.
Mr. Trump’s doctor also indicated in a release that the president had been taking a combination of over-the-counter drugs: zinc, vitamin D and famotidine (an antacid better known as Pepcid), as well as melatonin and aspirin.
Zinc, vitamin D and famotidine have been touted as helping fight the coronavirus, but the evidence is far from rigorous.
“They are not helpful for Covid,” Dr. Kalil said. And, he added, “they could have interactions” that make the disease worse.
A White House long in denial confronted reality this week after President Trump and the first lady both tested positive for the virus, along with a cadre of close advisers, including Hope Hicks, a top White House aide, and Bill Stepien, the Trump campaign manager.
The outcome appeared shocking but also inevitable in a West Wing that assumed that rapid virus tests for everyone who entered each morning were substitutes for other safety measures, like social distancing and wearing masks.
But the outcome was also a byproduct, former aides said, of the recklessness and top-down culture of fear that Mr. Trump created at the White House and throughout his administration. If you wanted to make the boss happy, they said, you left the mask at home.
The Biden campaign, after not answering repeated requests for more details on testing protocol and results following the president’s positive result, said on Saturday night that it would release the results of future tests, in an attempt to draw a contrast with the lack of clarity from the Trump White House on testing.
Later Saturday, Bloomberg News reported that another senior White House aide, Nick Luna, tested positive for the virus. An administration official confirmed that Mr. Luna, who serves as Mr. Trump’s “body man” and is constantly in proximity to him, tested positive.
President Trump at times told staff members wearing masks in meetings to “get that thing off,” an administration official said. Everyone knew that Mr. Trump viewed masks as a sign of weakness, officials said, and that his message was clear. “You were looked down upon when you would walk by with a mask,” said Olivia Troye, a top aide on the coronavirus task force who resigned in August and has endorsed former Vice President Joseph R. Biden Jr.
In public, some of the president’s favorite targets were mask-wearing White House correspondents. “Would you take it off, I can hardly hear you,” Mr. Trump told Jeff Mason of Reuters in May, then mocked Mr. Mason for wanting “to be politically correct” when he refused.
An event to celebrate President Trump’s nominee for the Supreme Court, Judge Amy Coney Barrett, has become the object of intense curiosity after several attendees, including the president and the first lady, tested positive for the coronavirus.
The ceremony, held last Saturday in the White House Rose Garden, was attended by multiple Republican members of the Senate Judiciary Committee, as well as many high-ranking White House advisers and aides.
Two senators who attended the event have tested positive. Thom Tillis, Republican of North Carolina, and Mike Lee, Republican of Utah, both of whom announced their test results on Friday, are among several people who have tested positive since attending the events last Saturday. Mr. Lee was recorded hugging several attendees with a mask in his hand just five days before he tested positive. Chris Christie, the former governor of New Jersey, attended the event and in the following days helped Mr. Trump prepare for his Tuesday presidential debate. He also has the virus.
Kellyanne Conway, a former White House counselor, and the Rev. John I. Jenkins, the president of the University of Notre Dame, also tested positive after attending.
The Sept. 26 ceremony does not appear to be a “super-spreader” event, in which a single infected person transmits the virus to many others, because most attendees have tested negative in recent days. Mr. Trump’s actual announcement took place outdoors. Indoor discussions were also held before and after the event inside the White House, where guests were more likely to spread the virus.
The president mingled with attendees in a reception in the Diplomatic Room, where few people, if any, were wearing masks, and met with Judge Barrett in the Oval Office.
Public health experts have cautioned that, because of the coronavirus’s incubation period, people who have been infected may not show symptoms or test positive for several days after exposure, adding to concern that more attendees may be infected.
The N.F.L. postponed a highly anticipated game scheduled for Sunday between the New England Patriots and the Kansas City Chiefs until Monday or Tuesday after positive coronavirus tests on both teams. According to multiple reports, Cam Newton, the Patriots quarterback, was among those who tested positive.
The Patriots confirmed a positive test but did not identify the player. In a statement released Saturday, the team said the player entered isolation and that subsequent testing on players and staff members who had been in contact with him had come back negative.
The new positive tests come after the N.F.L. spent much of the week scrambling to address an outbreak of positive tests among the Tennessee Titans. That team reported 11 positive tests among players and team personnel, which forced the league to push its scheduled Week 4 game against the Pittsburgh Steelers back to Oct. 25, Week 7 of the football calendar.
In a statement, the league said that the Patriots and the Chiefs were consulting with infectious disease experts and working closely with the N.F.L. and the players’ association “to evaluate multiple close contacts, perform additional testing and monitor developments.”
Chris Christie, the former governor of New Jersey who for several days this week helped the president prepare for the debate, said he had tested positive for the coronavirus.
Mr. Christie announced his condition on Saturday, becoming the latest of several Trump associates to get a positive test result.
“I want to thank all of my friends and colleagues who have reached out to ask how I was feeling in the last day or two,” he said on Twitter.
In another tweet later on Saturday, Mr. Christie said he had checked himself in to the Morristown Medical Center in Morristown, N.J., on Saturday afternoon after consulting with his doctors.
“While I am feeling good and only have mild symptoms, due to my history of asthma we decided this is an important precautionary measure,” he said.
Mr. Christie’s statement came one day after Bill Stepien, President Trump’s campaign manager, tested positive for the virus. An administration official confirmed late Saturday that Nick Luna, who serves as Mr. Trump’s “body man” and is constantly in proximity to him, also tested positive.
Mr. Christie and Mr. Stepien were among several advisers who huddled with Mr. Trump and others for debate preparation from Sunday to Tuesday.
That group also included Hope Hicks, one of Mr. Trump’s closest advisers, and Kellyanne Conway, the former senior White House aide, both of whom have since tested positive.
No one wore masks during the preparation, Mr. Christie said.
Ms. Conway and Mr. Christie also attended a White House event on Sept. 26 announcing Mr. Trump’s nominee for the Supreme Court, Judge Amy Coney Barrett.
Others who attended and said they have tested positive include Senator Mike Lee, Republican of Utah; Senator Thom Tillis, Republican of North Carolina; and the Rev. John I. Jenkins, the president of the University of Notre Dame.
There are those in Wisconsin who have begun to think of their state as a bit of a twofer when it comes to hot spots.
In recent weeks, the coronavirus has spiked in counties throughout the state. Then there is the matter of the presidential campaign and the seemingly unblinking attention that has been focused on Wisconsin voters lately.
On Saturday morning, the office of Senator Ron Johnson, Republican of Wisconsin, announced that he had tested positive for the coronavirus. It was not clear where Mr. Johnson contracted the virus, but his office said he was exposed earlier this week to an individual who tested positive.
Wisconsin residents have watched with growing alarm as virus cases have exploded. Three of the four metro areas in the United States with the most cases per capita were in northeastern Wisconsin, and one hospital in Green Bay was nearly full this week. On Saturday, the state reported 3,022 new infections, its highest one-day total.
“It’s just crazy here now,” said Steve VanderLoop, 64.
Several of his co-workers at a manufacturing plant, Mr. VanderLoop heard, have fallen ill from Covid-19. So did his brother-in-law’s entire family in nearby Washington County and a good friend up the shore of Lake Winnebago. Then the gut punch: His 96-year-old mother learned that she had the virus.
As Mr. VanderLoop spoke, he was standing on his porch, a cloth mask covering his face. Along the block, yards and fences were festooned with Biden signs, billowing Trump flags, hand-painted posters and bumper stickers with peace symbols.
“Then you throw in the campaign and everything else,” he said. “It’s a big snowball.”
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 about their health and the virus, taken from 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:
Ronna McDaniel, the chairwoman of the Republican National Committee
Hope Hicks, one of Mr. Trump’s most senior advisers
Bill Stepien, President Trump’s campaign manager
Kellyanne Conway, the former top White House adviser, who attended Judge Amy Coney Barrett’s Supreme Court nomination ceremony at the White House on Sept. 26
Senator Thom Tillis of North Carolina, who participated in a debate against his Democratic challenger on Thursday
Rev. John I. Jenkins, the president of the University of Notre Dame, who also attended the ceremony for Judge Barrett last week
Senator Ron Johnson of Wisconsin, who did not attend Judge Barrett’s ceremony last week
Chris Christie, the former governor of New Jersey
Nick Luna, Mr. Trump’s “body man”
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
Donald Trump Jr., Mr. Trump’s son
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
Senator Ben Sasse, Republican of Nebraska and a member of the Judiciary Committee. He attended Judge Barrett’s ceremony.
Senator Josh Hawley, Republican of Missouri and a member of the Judiciary Committee. He attended Judge Barrett’s ceremony.
More than 100,000 people in India have died from the coronavirus, the government said on Saturday, even as officials plan to lift more restrictions in hopes of reviving the crippled economy.
India’s health ministry reported 1,069 new Covid-19 deaths, bringing the official total to 100,842, though experts say the true toll is probably much higher. Until Saturday, only the United States and Brazil had reported more than 100,000 deaths from the virus.
At 6.4 million, India’s official caseload is the second-highest in the world, surpassed only by the United States, which has more than 7.3 million cases. India’s death and infection rates have climbed in recent months, with September alone accounting for more than 40 percent of its cases and about a third of its deaths.
The numbers have fallen somewhat since mid-September but remain high. And experts suspect that many Covid-19 fatalities in India have gone unreported.
Prime Minister Narendra Modi’s government imposed a harsh nationwide lockdown in March, a move that many experts say was poorly planned, devastating the economy while failing to stop the virus’s spread.
Now, despite the climbing numbers, officials are lifting restrictions in hopes of easing the economic suffering. Cinemas will be allowed to reopen with limited capacity this month, for example, and some states are expected to reopen schools.
In other global developments:
The Solomon Islands reported its first coronavirus case on Saturday, the local news media reported. The remote South Pacific nation had been one of few countries with no confirmed infections. But Prime Minister Manasseh Sogavare said in an address to the nation that a student had tested positive after arriving in Honiara, the capital, on a repatriation flight from the Philippines. He said that the student was asymptomatic and that the Health Ministry was tracing his contacts.
Israelis opposed to Prime Minister Benjamin Netanyahu and his handling of the pandemic protested across the country on Saturday night, despite new restrictions on public assembly, the Agence France-Presse reported. In Tel Aviv, the capital, demonstrators staged several simultaneous marches in different parts of the city, an A.F.P. photographer there said. The police did not give an estimate on the number of protesters. In Jerusalem, the Israeli news media estimated that about 200 people were protesting outside Mr. Netanyahu’s official residence, a marked contrast with the thousands who were there a week earlier. Parliament on Wednesday approved a law restricting demonstrations as part of a coronavirus-related state of emergency, which critics say is aimed at silencing protests against Mr. Netanyahu.
President Xi Jinping of China on Saturday sent a message to President Trump wishing him and the first lady a speedy recovery. In the message to Mr. Trump, Mr. Xi said that he and his wife, Peng Liyuan, “express sympathy and hope you get better soon,” according to a report in The Global Times, a Chinese news outlet controlled by the ruling Communist Party. The message from the Chinese leader comes as the two men have found themselves increasingly at odds as the coronavirus spread around the world and widened a schism between the two superpowers.
Experts have warned that fall will be a uniquely challenging time for combating the pandemic, yet one of the most essential tools for stemming the spread of the coronavirus still has not been widely deployed in the United States and Europe.
While Western nations vowed repeatedly to develop “world-beating” contact tracing and testing operations at the onset of the pandemic, counting and monitoring people who have been exposed to the virus, and who may expose others, has rarely been effectively implemented.
Beholden to privacy rules, Western officials largely trusted people to hand over names to contact tracers. But that trust was not repaid, in large part because governments neglected services that were crucial to winning people’s cooperation: a fast and accurate testing system, and guarantees that people would be housed, fed and paid while they isolated.
Elected officials presented the system as a critical bridge between lockdown and a vaccine, allowing them to contain small outbreaks without shutting down large parts of society. But construction of that bridge has been rocky at best.
“Public health leaders fell in love with the idea of contact tracing as an important tactic — and it is — but that’d be like if you’re going into war and were just talking about the tanks,” said Brian Castrucci, president of the de Beaumont Foundation, a public health charity in Maryland.
The West’s public health systems have not matched the success in parts of East Asia where the fear of epidemics became more ingrained after SARS appeared in 2002 and MERS was identified in 2012.
In England, people are neither handing over many contacts — about five, on average — nor following the rules.
“It suggests there is some degree of skepticism in the population to engagement,” said Professor Christophe Fraser of the University of Oxford, an adviser to the British government’s tracing program, referring to the proportion of known cases — a fifth — who handed over no other names.
In Afghanistan, the numbers of women reported to have tested positive for the virus and to have died of Covid-19 are far below the numbers reported for men. Globally, men account for 53 percent of confirmed cases and 58 percent of deaths, according to the independent research group Global Health 50/50. But in Afghanistan, men account for 70 percent of cases and 74 percent of deaths — a discrepancy that experts say is most likely the result of women being shut out of the health care system and the public sphere.
Afghan women face obstacles within both their own households and the health care facilities themselves, said Suraya Dalil, who was Afghanistan’s public health minister from 2010 to 2014 and now leads special programs in public health at the World Health Organization. “Women have to be accompanied by somebody to go to the hospital,” she said, “so those decisions are often made by the men in a household, whether it’s the husband or the father or the son.”
And when women do get to health care facilities, they are expected to engage only with female doctors, she added. That becomes nearly impossible given the small number of female doctors.
Another explanation for the gap could be that Afghanistan’s labor force is male-dominated. A study published by the Center for Economic Policy Research in London found a positive correlation between women’s participation in the work force and Covid-19 death rates. In Afghanistan, women make up only about 30 percent of the work force.
All of this brings into sharp focus how much hangs in the balance for Afghan women as the government holds peace negotiations with the Taliban.
Nearly 10,000 doctors took part in a strike in Peru this week to demand more support from the government as they respond to one of the world’s worst outbreaks of the coronavirus, a union leader said, the latest in a series of protests by public health workers who have endured months of crises at the country’s underfunded hospitals.
The nationwide strike forced Peru’s second-biggest health care provider, the state-run EsSalud, to suspend consultations and scheduled surgeries on Tuesday and Wednesday, said Dr. Teodoro Quiñones, the secretary general of EsSalud’s doctors’ union.
Included in the doctors’ demands was the distribution of a $200 monthly cash bonus that the government promised front-line medical workers months ago. Dr. Quiñones said most doctors had yet to receive the bonus despite being forced to buy their own face masks while working at hospitals that lacked even the most basic medical supplies.
“Do you know the desperation of tending to patients in these conditions? Without oxygen? Without medicine? To see a patient on a ventilator wake up with a tube in their mouth and not have the medicine to sedate them?” Dr. Quiñones said in a telephone interview.
Despite an early and strict lockdown, Peru has suffered one of the highest per capita Covid-19 death tolls in the world, with about 100 confirmed deaths from the disease for every 100,000 people. The pandemic has exposed the shortcomings of a health care system that has had to turn away patients as demand for beds surged for months, before hospitalizations peaked in mid-August and deaths started to decline.
The strike was just one of several disputes over pay and working conditions between the government and public sector health workers. Another doctors’ group held a two-day strike a month ago, and Dr. Quiñones said different unions might team up to hold a bigger, indefinite strike if the government does not address their concerns.
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, but the timing raises the possibility that he could have been infected last 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.
President Xi Jinping of China on Saturday sent a message to President Trump wishing him and the first lady a speedy recovery after the pair tested positive for the coronavirus, the latest addition to a growing list of world leaders who have wished the American president well.
In the message to Mr. Trump, Mr. Xi said that he and his wife, Peng Liyuan, “express sympathy and hope you get better soon,” according to a report in The Global Times, a Chinese news outlet controlled by the ruling Communist Party.
The message from the Chinese leader comes as the two men have found themselves increasingly at odds as the coronavirus spread around the world and widened a schism between the two superpowers.
Mr. Trump has been an outspoken critic of China’s handling of the coronavirus, often calling it the “Chinese virus.” He has regularly pointed to its origins in the central Chinese city of Wuhan and its swift spread around the world as a failure by China. In a broadcast at this year’s United Nations General Assembly, Mr. Trump demanded that the global body hold accountable “the nation which unleashed this plague onto the world.”
Leaders around the world have sent messages of support to Mr. Trump since he announced early Friday that he had contracted the virus. Prime Minister Jacinda Ardern of New Zealand said on Saturday that she was sending him and the first lady, Melania Trump, “New Zealand’s best wishes for a speedy recovery,” adding that “this is, obviously, a virus that has had a devastating impact.”
President Jair Bolsonaro of Brazil in a Facebook post late on Friday also wished Mr. Trump well: “You will win and come out stronger, for the good of the USA and the world.”
Prime Minister Boris Johnson of Britain, speaking to reporters on Saturday, said he had “no doubt” that Mr. Trump would “make a very strong recovery.” Mr. Bolsonaro and Mr. Johnson are among a growing list of world leaders who have contracted the virus.
North Korea’s leader, Kim Jong-un, sent a message of sympathy to Mr. Trump on Saturday, the country’s official Korean Central News Agency said.
“He sincerely hopes that they will recover as soon as possible,” it said in a brief dispatch. “He sent warm greetings to them.”
Mr. Kim and Mr. Trump have met three times, building what both leaders called a special “friendship,” although they have not reached agreement on eliminating the North’s nuclear weapons program.
On Wednesday night, President Trump spoke for 45 minutes to a jubilant and carefree crowd of 3,000 at the airport in Duluth, Minn.
But now, attendees are replaying the event in their heads with one new and gut-wrenching piece of information: Mr. Trump is infected with the coronavirus.
Big rallies are a signature of Mr. Trump’s campaigning, and he had for months been pushing to bring them back, even as coronavirus case numbers remained high across the United States and as experts warned of the risks of bringing together large groups of people. In recent weeks, he staged rallies in outdoor airport hangars in battleground states like North Carolina, Pennsylvania, Arizona, New Hampshire and — on Wednesday night — Minnesota.
The Duluth crowd was the last of such a scale to see Mr. Trump before the announcement of his coronavirus diagnosis early Friday, although he also attended a private fund-raiser near the Twin Cities.
Elected officials who recently met with Mr. Trump are now taking precautions. Some said on Friday that they were being tested for the coronavirus, and a few Republican leaders from Minnesota have put themselves into quarantine in case they were exposed.
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 in late March, 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, the 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 had been 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 was quite possible that he was exposed to the virus on that day.
After months of wishing that the coronavirus would “disappear, like a miracle” and insisting that the United States was “rounding the corner” in its fight against the pandemic, President Trump announced on Friday that he and the first lady had tested positive for the virus.
Now, the White House itself is a hot spot of sorts, the center of a contact tracing effort that extends to the upper reaches of American politics and government. It is not clear exactly when Mr. Trump was infected or by whom, but there is little doubt that the virus was circulating around him for the past week:
Last Friday, the chairwoman of the Republican National Committee, Ronna McDaniel, mingled with Mr. Trump at a glitzy fund-raiser at the Trump International Hotel in Washington. The president seemed to be in good cheer and good health.
The next afternoon, he gathered Republican lawmakers and members of conservative interest groups in the White House Rose Garden to announce Judge Amy Coney Barrett as his Supreme Court nominee.
Ms. McDaniel was not present, having traveled to her home in Michigan. It would be a few days before she began to feel ill and then tested positive for the virus. But the newly renovated Rose Garden was packed with supporters of Mr. Trump, including at least eight Republican senators, few of them wearing masks. Judge Barrett, who is said to have already had the coronavirus and has since recovered, met earlier with the president in the Oval Office without wearing a mask.
Later Saturday evening, Mr. Trump flew to Middletown, Pa., for a campaign rally. A White House reporter on the flight would later test positive for the virus.
Back at the White House on Sunday, Mr. Trump and Hope Hicks, one of his closest advisers, huddled with a handful of other aides, none of whom wore masks, for debate preparation in the Map Room. The group included Stephen Miller, the president’s speechwriter and top domestic policy adviser; Chris Christie, the former governor of New Jersey; and Rudolph W. Giuliani, Mr. Trump’s personal lawyer and the former mayor of New York.
On Monday, the group moved their session into the Oval Office. Ms. Hicks sat on the couch. And on Tuesday, they gathered again for a few hours in the Map Room, prepping the president for the debate that evening.
Before the debate, White House officials who had been in close contact with Mr. Trump and Ms. Hicks headed to Capitol Hill to introduce Judge Barrett to senators. Vice President Mike Pence; Mark Meadows, the White House chief of staff; and Pat Cipollone, the White House counsel, posed for photographs in the Mansfield Room with Judge Barrett and Senator Mitch McConnell of Kentucky, the majority leader.
The lawmakers and White House officials posed without masks.
Mr. Trump and the first lady, Melania Trump, left for the debate in Cleveland on Tuesday afternoon. Ms. Hicks traveled with the president, as did Representative Jim Jordan, Republican of Ohio.
On Wednesday, as Ms. McDaniel received her positive test results, Mr. Trump met in the Oval Office with Mr. Meadows, his chief of staff, and Steven Mnuchin, the Treasury secretary, to discuss the stalled negotiations with Democrats on a compromise stimulus bill.
On Wednesday evening, the entire Republican congressional delegation from Minnesota — Representatives Pete Stauber, Jim Hagedorn and Tom Emmer, the chairman of House Republicans’ campaign arm — flew with Mr. Trump to another campaign rally. In a photo they later posted on Twitter, none were wearing masks on the plane.
On Thursday morning, Senator Mike Lee of Utah, who had attended the Rose Garden event, began to feel ill, with symptoms consistent with longtime allergies, according to his office. Around the same time, Ms. Hicks was tested.
The White House did not announce that Ms. Hicks had tested positive before the news leaked out on Thursday evening. Hours later, after midnight, Mr. Trump turned to Twitter to announce: “Tonight, @FLOTUS and I tested positive for COVID-19. We will begin our quarantine and recovery process immediately. We will get through this TOGETHER!”
President Trump, like many men in their 70s, has mild heart disease. He takes a statin drug to treat high cholesterol and aspirin to prevent heart attacks. And at 244 pounds in a health summary released in June, he has crossed the line into obesity.
All of that, experts say, puts him at greater risk for a serious bout of Covid-19. So far, White House officials say Mr. Trump’s symptoms are mild — a low-grade fever, fatigue, nasal congestion and a cough — but it is far too soon to tell how the disease will progress.
“He is 74, he’s hefty and he’s male, and those three things together put him in a higher-risk group for a severe infection,” said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University in Tennessee, adding: “Although he is being watched meticulously and may well do fine for a few days, he is not out of the woods, because people can crash after that period of time. This is a very sneaky virus.”
Already, his doctors have taken extraordinary steps. On Friday they gave him a single infusion of an experimental antibody cocktail that is showing promising results in early clinical trials. He is also taking vitamin D, zinc, melatonin, famotidine (an antacid better known as Pepcid) and daily aspirin, according to a memo from Dr. Sean P. Conley, the president’s physician.
As is the case with all Covid-19 patients, Mr. Trump’s overall health will make a difference in how he fares. Data from the Centers for Disease Control and Prevention shows that about 64.7 percent of Covid-19 patients with underlying health conditions in his age group have required hospitalization, and 31.7 percent have died.
Mr. Trump’s true condition, though, may remain a mystery. The president has never been forthcoming about his health — apart from boasting that he is in excellent physical condition — and has never released complete medical records as presidents before him did. In recent years, he has faced increasing questions on the subject.
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 isolation, 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 had tested positive on 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.”
Ms. Conway is one of several people to have said they had tested positive for the coronavirus after attending White House events last Saturday announcing Mr. Trump’s nominee for the Supreme Court, Judge Amy Coney Barrett. Others include Senator Mike Lee, Republican of Utah; Senator Thom Tillis, Republican of North Carolina; and the Rev. John I. Jenkins, the president of the University of Notre Dame.
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 that the president had “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 on 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 had been 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 — were decided on a case-by-case basis and that Mr. Trump was 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.