She had been isolating in South Carolina, where she tested positive for the virus as the couple wrapped up a vacation there last week. The president made a brief stop at the White House before going to Wilmington, Delaware. He arrived in Rehoboth Beach on Saturday night.
The White House announced Tuesday that the 71-year-old first lady had tested positive for the virus. She first had symptoms last Monday. Like the president, she has been twice-vaccinated and twice-boosted with the Pfizer COVID-19 vaccine.
President Biden, 79, recovered from a rebound case of the virus on Aug. 7.
Jill Biden was prescribed the antiviral drug Paxlovid and isolated for five days at the home on Kiawah Island, South Carolina, where they vacationed, before receiving negative results from two consecutive COVID-19 tests, spokeswoman Elizabeth Alexander said Sunday.
The first lady rejoined the president in Rehoboth Beach on Sunday afternoon, an aide said.