Biden, who is currently in Rehoboth Beach, Delaware, tested positive again for Covid-19 with an antigen test on Wednesday. She tested negative during a routine test on Tuesday.Donohue says the first lady has not had a reemergence of symptoms. She added that a “small number of close contacts” with whom Biden had recent contact have been notified.Biden first tested positive on August 15 while vacationing in Kiawah Island, South Carolina. The first lady had “cold-like symptoms,” according to Alexander, and was put on a cycle of the antiviral drug Paxlovid, which can trigger a rebound case of Covid-19 in some people several days after a negative test result.Biden had two consecutive negative tests on Sunday and traveled from South Carolina to join President Joe Biden in Delaware. Read MorePresident Biden tested negative Wednesday, a White House official told CNN. Following US Centers for Disease Control and Prevention guidelines, the President will mask for 10 days indoors because he is considered a close contact, the official said.The President also took Paxlovid when he had Covid-19 last month, and he eventually tested positive for a rebound case of Covid-19, following initial negative tests. Donohue told CNN that Jill Biden will remain at the family beach house in Delaware until she once again has two consecutive negative test results.