By Jeff Mason WASHINGTON (Reuters) -President Joe Biden’s COVID-19 symptoms continue to improve and now include “less troublesome” sore throat, runny nose, loose cough and body aches, his physician, Dr. Kevin O’Connor, said in a memo on Saturday. Biden’s lungs remain clear and his oxygen saturation “continues to be excellent on room air,” the doctor said. Biden, 79, tested positive for COVID on Thursday, when the White House said he was experiencing mild symptoms. His diagnosis came as a highly contagious subvariant of the coronavirus drives a new wave of cases in the United States. Biden most…