U.S. President Joe Biden. (Kyodo)

U.S. President Joe Biden continues to test positive for the novel coronavirus, although he feels "very well" and his cough has nearly resolved, his physician said Friday.

The 79-year-old initially tested positive on July 21 and has experienced mild symptoms. He received negative test results at one point, but tested positive again last Saturday in what is believed to be a "rebound" case after taking antiviral medication.

Biden has also experienced a return of a cough, but his physician Kevin O'Connor said the symptom has "almost completely resolved."

The president will continue to work while in isolation, the doctor said in a statement.