Jill Biden has been forced to isolate again after testing positive for a rebound case of COVID-19.
The first lady initially tested positive for the virus on Aug. 16. She was treated with Paxlovid, an antiviral medication.
A spokesperson for Mrs. Biden said she tested negative twice on Sunday. However, upon re-testing on Wednesday, she received a positive result.
The first lady's spokesperson said she has not experienced a reemergence of symptoms, but will isolate in Delaware as a precaution.
President Joe Biden also suffered a case of rebound COVID-19 after initially testing positive in late July.
According to a study by the National Institutes of Health, up to 5% of people given Paxlovid suffered a rebound infection.