First lady Jill Biden tested positive for COVID-19 on Wednesday in a “rebound” case, her office said.
The first lady — who first tested positive on Aug. 16 — received her second negative test on Sunday and joined the president in Delaware, coming out of her isolation period spent in South Carolina. She again tested negative on Tuesday, her deputy communications director Kelsey Donohue said.
The president tested negative for COVID-19 on Wednesday, according to the White House.
“The First Lady has experienced no reemergence of symptoms, and will remain in Delaware where she has reinitiated isolation procedures,” Donohue said in a statement on Wednesday. “The White House Medical Unit has conducted contact tracing and close contacts have been notified.”
The president returned to the White House from Delaware on Wednesday morning. The first lady was supposed to accompany her husband to a Democratic National Committee event in Maryland on Thursday but will now remain isolated in Delaware.
The president “will mask for 10 days when indoors and in close proximity to others,” a White House official said. “We will also keep the President’s testing cadence increased and continue to report those results.”
Jill Biden, who is double vaccinated and twice boosted, was prescribed the antiviral treatment Paxlovid, which President Biden also took after testing positive last month. Like his wife, the president also suffered a rebound COVID-19 case.
Paxlovid is authorized under emergency use by the Food and Drug Administration for Americans ages 12 and older who are at high-risk for severe illness from COVID-19. Preliminary estimates suggested that the drug provided an 89% reduction in virus-related hospitalizations and deaths.
However, in recent months, as use of the drug ramped up, there was an increasing number of anecdotal reports of rebound cases, where individuals test positive for COVID-19, after testing negative, following completion of the treatment course. According to the Centers for Disease Control and Prevention, a COVID-19 rebound has been reported to occur between two and eight days after initial recovery.
Although experts say preliminary estimates of Paxlovid rebounds are likely undercounted, White House COVID-19 Response Coordinator Dr. Ashish Jha suggested after President Biden’s Paxlovid rebound that the phenomenon may happen in 5% to 8% of patients.
Federal officials report that a rebound infection can also occur in patients receiving no treatment or in patients receiving other COVID-19 therapeutics.