Misinformation spikes as Trump confirms COVID-19 diagnosis

President Trump received an experimental drug for what the White House described as mild symptoms of the virus. Vice President Mike Pence, Joe Biden and Speaker Nancy Pelosi have tested negative.

This briefing has ended. Follow our latest coverage of the coronavirus pandemic.

Here’s what you need to know:

• The president has a fever, congestion and a cough, people close to him say, and he will be hospitalized for several days.

• Bill Stepien, Trump’s campaign manager, tests positive for the virus.

• The next week is the critical phase in Trump’s illness. Here are the risks he faces.

• Trump received an experimental antibody treatment from Regeneron.

• Trump recently traveled to and from 3 states with a packed schedule before he learned he tested positive.

• Biden tests negative for the virus, his doctor says.

• White House rapid testing product is known to deliver incorrect results.

• The president of Notre Dame tests positive, less than a week after a White House visit.

• Azar defends refusal of Trump family members to wear masks at the debate.

• News that the president contracted the virus leaves the world shaken.

President Trump boarded Marine One, wearing a mask, on his way to Walter Reed National Military Medical Center.CreditCredit...Doug Mills/The New York Times

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.

Trump departs for Walter Reed Medical Center

Researchers at Cornell University published a study this week showing that Mr. Trump was the single largest driver of false and misleading information about the coronavirus. Mentions of Mr. Trump made up nearly 38 percent of the overall “misinformation conversation,” the researchers said.

Mr. Trump has also stated on at least 34 separate occasions since February that the coronavirus would go away.

“We’re in an environment where conspiracies are thriving, in part because the president encourages them,” said Melissa Ryan, chief executive of Card Strategies, a consulting firm that researches disinformation. “And we have a White House comms operation that gives the press and public disinformation constantly.”

The situation has created “the perfect storm for people to assume that the White House isn’t being truthful,” Ms. Ryan said.

Many of the deniers also latched on to a tweet from Sept. 18 that had originally been shared in conspiracy circles, but was reshared widely on Facebook and Twitter after Mr. Trump’s announcement on Friday. “Trump’s October surprise will be the announcement of ‘his infection,’” it said. “Fake, but quite dramatic.” The post collected nearly 15,000 interactions across Facebook and Twitter, mostly from people who falsely asserted that Mr. Trump catching the virus was a known plan.