Updated July 30, 2022 at 3:28 PM ET
President Biden has tested positive for COVID-19 again, Dr. Kevin O'Connor, his physician, says.
"After testing negative on Tuesday evening, Wednesday morning, Thursday morning and Friday morning, the President tested positive late Saturday morning, by antigen testing," the doctor said in a letter released by the White House.
O'Connor said Biden is not experiencing symptoms, and feels well. The doctor said there's no reason to reinitiate treatment with Paxlovid at this time, but the president will "reinitiate strict isolation procedures."
Biden wrote on Twitter: "Folks, today I tested positive for COVID again. This happens with a small minority of folks. I've got no symptoms but I am going to isolate for the safety of everyone around me. I'm still at work, and will be back on the road soon."
Biden, 79, is fully vaccinated and has had two booster shots. He first tested positive on July 21.
He was treated with a five-day course of Paxlovid, an antiviral pill that's been found to be highly effective at reducing the risks of hospitalization and death for COVID-19 patients with mild or moderate symptoms. But some people who take Paxlovid experience a "rebound," where a person can once again test positive between two and eight days after symptoms have faded and having tested negative.
"Limited information currently available from case reports suggests that persons treated with Paxlovid who experience COVID-19 rebound have had mild illness; there are no reports of severe disease," the Centers for Disease Control and Prevention said about the phenomenon.
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