Washington — President Biden tested negative for COVID-19 on Saturday after a weeklong rebound infection. 

His physician, Dr. Kevin O'Connor, said in a letter that Mr. Biden "will continue his strict isolation measures pending a second negative test."

    "The President continues to feel very well," O'Connor said.

    Mr. Biden had experienced a "rebound positivity," which occurs in a small percentage of patients taking the antiviral treatment Paxlovid.

    For the past week, the president has been working from the Executive Residence in isolation.  

    Mr. Biden first tested positive for COVID-19 about three weeks ago and began a course of Paxlovid. He then received a negative test days later and ended his isolation. But last Saturday, O'Connor said the president tested positive once again, though he was not experiencing symptoms.