STORY: U.S. President Joe Biden tested positive for COVID-19 — again — in what the White House doctor described as a “rebound” case seen in a small percentage of patients who take the antiviral drug Paxlovid.The 79-year-old president, who emerged from isolation on Wednesday after testing positive earlier this month, issued a video statement on Saturday:“Hi folks, Joe Biden here. Tested positive this morning. Going to be working from home the next couple of days. And I’m feeling fine, everything’s good.”Biden will return to strict isolation, according to the White House, and will cancel planned trips to his home in Wilmington and work trip in Michigan.Studies have shown that a small percentage of people taking Paxlovid – used to treat high-risk patients – will suffer a relapse or rebound days after the five-day treatment course has ended. The White House doctor said there is no plan to reinitiate treatment given Biden’s lack of symptoms.