President Joe Biden tested negative for Covid Saturday but will continue to isolate until he tests negative a second time, his doctor said in a letter.
"The President continues to feel very well," Dr. Kevin O’Connor, the White House physician, wrote a week after Biden, 79, tested positive in a "rebound" case of Covid. "This morning, his SARS-CoV-2 antigen testing was negative."
He will continue "his strict isolation measures pending a second negative test as previously described," O'Connor added.
Biden, who is fully vaccinated and twice boosted, first tested positive for Covid on July 21 during a routine test and was treated with the antiviral Paxlovid. The president had tested negative several days in a row before he tested positive again last Saturday in what O'Connor described as a "rebound" case.
O'Connor said in a letter last week that Biden was doing well and would not reinitiate treatment.
A small minority of people who take Paxlovid to treat Covid experience a rebound case. Around 1% to 2% of people who took Paxlovid in Pfizer’s clinical trial tested positive for the coronavirus after having tested negative. Rebound rates are around 5% among the tens of thousands of people who’ve taken the drug in real-life settings, Dr. Ashish Jha, the White House Covid response coordinator, said.
Dr. Anthony Fauci, chief medical adviser to Biden, who had Covid in June, said he also experienced Paxlovid rebound.
The Centers for Disease Control and Prevention warned of possible recurrences in May, and said that people who test positive again may still be contagious and should restart isolation for at least five days.