Biden, 79, tests positive for the coronavirus.

WASHINGTON — President Biden tested positive on Thursday for the coronavirus, raising health concerns for the 79-year-old president and underscoring how the virus remains a persistent threat in a country trying to put the pandemic in the past.

In a statement, the White House press secretary Karine Jean-Pierre said that Mr. Biden “tested positive for Covid-19. He is fully vaccinated and twice boosted and experiencing very mild symptoms.”

Mr. Biden is receiving Paxlovid, an antiviral drug used to minimize the severity of Covid-19, Ms. Jean-Pierre said. The president will isolate at the White House but will “continue to carry out all of his duties fully during that time,” she said.

The president was scheduled to fly to Pennsylvania on Thursday for a speech about gun violence and then to travel to his home in Wilmington, Del., where he was expected to stay for the weekend. Chris Meagher, a White House spokesman, said the Pennsylvania trip had been canceled.

Jill Biden, the first lady, tested negative this morning, according to Michael LaRosa, her spokesman.

Mr. Biden’s positive test came amid a flurry of virus cases as the nation grapples with new subvariants that doctors say are highly contagious and can more easily evade the protections provided by coronavirus vaccinations.

Representative Bennie Thompson of Mississippi, the chairman of the House committee investigating the Jan. 6 attack on the Capitol, announced on Tuesday that he had tested positive for the coronavirus and would not appear in person at what could be the panel’s last hearing this summer.

In May, Xavier Becerra, the secretary of health and human services, tested positive for the virus, and the White House announced that Ashley Biden, Mr. Biden’s daughter, had tested positive as well. Neither was considered a close contact of the president’s.

A number of members of Congress have also reported virus cases in recent weeks. And members of Mr. Biden’s inner circle have tested positive in recent months, including Secretary of State Antony J. Blinken, Vice President Kamala Harris and Jen O’Malley Dillon, his deputy chief of staff.

Even as administration officials and lawmakers in Washington reported infections, the president has continued to travel and appear at events, adhering to what his advisers said was guidance laid out by the Centers for Disease Control and Prevention and mask guidance issued by the District of Columbia.

In her statement, Ms. Jean-Pierre said officials would inform any members of Congress, journalists or others who would be considered close contacts of the president during a trip to Massachusetts on Wednesday.

“Consistent with White House protocol for positive Covid cases, which goes above and beyond C.D.C. guidance, he will continue to work in isolation until he tests negative,” Ms. Jean-Pierre said in the statement. “Once he tests negative, he will return to in-person work.”

Mr. Biden is fully vaccinated, has received two booster shots and is regularly tested, officials said. The president’s last Covid test was on Tuesday, when he had a negative test result, officials said on Thursday.

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