U.S. President Joe Biden tested positive again for COVID-19 on Wednesday, his physician Kevin O'Connor said in a memo released by the White House, adding that the test was taken after Biden finished a light workout.

Biden continues to feel well and is fever free, O'Connor said, adding that the president is still experiencing an occasional cough but less frequently than on Tuesday.

Biden, 79, had just emerged from isolation on Wednesday last week after testing positive for COVID for the first time on July 21. He tested positive again on Saturday in what O'Connor described as a "rebound" case seen in a small percentage of patients who take the antiviral drug Paxlovid.