WASHINGTON — President Biden tested positive on Thursday for the coronavirus, raising health concerns for the 79-year-old president and underscoring that the virus remains a persistent threat in a country trying to put the pandemic in the past.
Karine Jean-Pierre, the White House press secretary, said in a statement that Mr. Biden was “fully vaccinated and twice boosted and experiencing very mild symptoms.”
Dr. Kevin O’Connor, the president’s physician, said in a letter released by the White House that Mr. Biden was experiencing fatigue, a runny nose and an occasional dry cough.
“I anticipate that he will respond favorably, as most maximally protected patients do,” Dr. O’Connor wrote.
The president is receiving Paxlovid, an antiviral drug used to minimize the severity of Covid-19, Ms. Jean-Pierre said. He will isolate himself at the White House but “continue to carry out all of his duties fully during that time,” she said.
Mr Biden posted a tweet in the afternoon saying he was “doing great” and “keeping busy!”
In a short video posted to Twitter, Mr. Biden thanked people for their concern and said he was “doing well, getting a lot of work done.” In the video, Mr. Biden is shown standing near a balcony overlooking the South Lawn of the White House, dressed in a suit but with no tie.
“Keep the faith,” Mr. Biden says in the video. “It’s going to be OK.”
He had been scheduled to fly to Pennsylvania on Thursday for a speech about gun violence and then to travel to his home in Wilmington, Del., for the weekend. White House officials said both trips had been canceled.
Dr. Ashish K. Jha, Mr. Biden’s coronavirus response coordinator, said at a White House briefing that he believed the president was not at serious risk of severe illness given that he is fully up-to-date on his vaccines and is taking Paxlovid .
“Because the president is fully vaccinated, double boosted, his risk of serious illness is dramatically lower,” Dr. Jha said, adding, “Our expectation is that he’s going to have mild illness.”
Mr. Biden will isolate for five days in the White House residence, Dr. Jha said, and will only resume normal activities once he tests negative.
Vice President Kamala Harris, who was last with the president on Tuesday, tested negative, according to the White House. Jill Biden, the first lady, tested negative as well on Thursday morning, according to Michael LaRosa, her spokesman. Ms. Harris and Dr. Biden have also received two boosters.
The president’s diagnosis was a moment his aides had spent years bracing for. As a candidate in 2020, Mr. Biden took extraordinary measures to avoid becoming sick, holding “drive-in rallies” and avoiding the in-person events that had been hallmarks of life on the campaign trail.
As president, he remained severely isolated in his first months in office as the virus emerged. The number of staff members he interacted with was limited. Members of the news media and others were tested regularly. Mr. Biden and his staff wore masks at all times.
More recently, however, as the number of vaccinated people increased and many Americans shrugged off pandemic concerns, the president largely resumed regular activity. Last week, he returned from Israel and Saudi Arabia, where he shook hands and embraced many world leaders.
At home, Mr. Biden rarely wears a mask and has hosted crowded events at the White House, even as the nation grapples with a flurry of cases from new subvariants that are highly contagious and can more easily evade vaccine protections.
His advisers say he has adhered to guidance from the CDC and the District of Columbia.
In her statement, Ms. Jean-Pierre said officials would inform any members of Congress, journalists or others considered to have been close contacts with the president during a trip to Massachusetts on Wednesday.
“Consistent with White House protocol for positive Covid cases, which goes above and beyond CDC guidance, he will continue to work in isolation until he tests negative,” she said in the statement. “Once he tests negative, he will return to in-person work.”
Mr. Biden is regularly tested. His last test of him was on Tuesday, when he had a negative result, officials said on Thursday.
It was unclear exactly how he got infected, and White House officials declined to offer detailed information about who he was in contact with in recent days. It is difficult to determine exactly how or when someone contracted the virus.
Mr. Biden had a series of close calls before becoming infected. In March, I attended a gala event with Prime Minister Micheal Martin of Ireland, who left after testing positive.
Mr. Biden also attended the White House Correspondents’ Association Dinner in May, and a number of attendees tested positive afterward, including Secretary of State Antony J. Blinken.
Mr. Biden and his top aides have urged people to get vaccinated and receive boosters. The vaccine is very effective at keeping people from becoming seriously ill or dying, even when breakthrough infections occur.
The president and Democratic lawmakers have pleaded with Republicans in Congress to pass emergency coronavirus funds to ensure that the United States can purchase new vaccines and therapeutics.
Mr. Biden is the second president to be infected with the coronavirus. In October 2020, President Donald J. Trump tested positive and was taken by helicopter to Walter Reed National Military Medical Center, where he was given steroids and other treatments.
Mr. Trump and his aides downplayed his symptoms at the time, but reporting later revealed that he was very sick.
Noah Weiland and Katie Rogers contributed reporting.