By this point, many people can identify symptoms of COVID-19 -- fever, fatigue, shortness of breath -- but fewer know that those can occur after a successful recovery and closely resemble another illness: chronic fatigue syndrome. "There may well be a post-viral syndrome associated with COVID-19," Dr. Anthony Fauci, the nation's top infectious disease doctor, said at a July news conference organized by the International AIDS Society. "I know, because I follow on the phone a lot of people who call me up and talk about their course." Although chronic fatigue syndrome is still poorly understood, the CDC said as many as 2.5 million Americans may suffer from it.