President Joe Biden on Friday tested positive for COVID-19 for the seventh straight day after he experienced a “rebound” of the infection following his treatment with Paxlovid.
Biden’s physician, Kevin O’Connor, said that the president “continues to feel very well.”
“His cough has almost completely resolved,” O’Connor wrote in a letter provided by the White House. “His temperature, pulse, blood pressure, respiratory rate and oxygen saturation remain entirely normal. His lungs remain clear.”
Biden first tested positive for COVID-19 on July 21. Following two negative tests, he ended his isolation last week before testing positive again on Saturday.
Rebound cases have been known to happen in people who take Paxlovid, an antiviral drug. Biden underwent a five-day course of the treatment.
According to Ashish Jha, the White House COVID-19 response coordinator, rebound cases typically don’t lead to serious illness. He estimated that between 5-8% of Paxlovid users will see COVID-19 rebound.
Guidance from the Centers for Disease Control and Prevention states that those with rebound infections after taking Paxlovid should restart isolation and wear a mask for at least 10 days after rebound symptoms began.
“Some people continue to test positive after day 10 but are considerably less likely to shed infectious virus,” the CDC said in a health advisory issued in May.
A recent study found that COVID-19 rebound can also happen in people who did not take Paxlovid. The research, which hasn’t been peer reviewed, found that 27% of untreated study participants reported a rebound in COVID-19 symptoms within about a month of testing positive.