(NewsNation) — First lady Jill Biden tested positive Wednesday for a “rebound” case of COVID-19, according to a statement from the Office of the First Lady.
Biden, 71, has been twice-vaccinated and twice-boosted. She was prescribed the anti-viral drug Paxlovid after she tested positive for COVID-19 on Aug. 16, experiencing “mild symptoms.”
Biden tested negative for COVID-19 Sunday. She had isolated for five days and received negative results from two consecutive coronavirus tests.
According to the statement, the first lady has experienced no reemergence of symptoms with her “rebound” case and will isolate in Delaware.
The statement also stated Biden’s close contacts have been notified.
Because President Joe Biden is a close contact of the first lady, he will mask for 10 days when indoors and in close proximity to others, according to the White House.
President Biden had also experienced a “rebound” case of COVID, testing positive following treatment and several negative tests.
Dr. Anthony Harris, CEO of Hfit Health, told NewsNation a “rebound case” is “extremely uncommon.”
“It’s about 1% of the population treated with Paxlovid that experience a rebound,” Harris said. “The good news is that we shouldn’t be seeing this occur in the general population, again, no more than 1%.”
In accordance with the Centers for Disease Control and Prevention guidelines, the first lady will reenter isolation for at least five days.
The agency says most “rebound” cases remain mild and that severe disease during that period has not been reported.
Paxlovid was developed by the pharmaceutical company Pfizer and was the first pill approved by the Food and Drug Administration for the treatment of COVID-19.
Data from Pfizer shows some people treated with Paxlovid can experience a rebound after the completion of a round of treatment. Users will test negative and then suddenly begin testing positive again.
Dr. Anthony Fauci, the nation’s top infectious disease expert, took Paxlovid after testing positive for COVID. He also said he had a recurrence of symptoms after completing a full round of treatment.