Nearly 20% of young, healthy coronavirus patients hadn't recovered after 2 to 3 weeks, the CDC found — showing infection can cause 'prolonged illness' COVID-19 patients with mild symptoms may still develop chronic illness related to the disease, a new CDC report found. More than a third of patients surveyed said they hadn't returned to their usual state of health two to three weeks after they were tested. That included nearly 20% of young, previously healthy respondents. Beyer, a 27-year-old who lives in Austin, Texas, is one of many young patients who have been sick with COVID-19 for months. A new report from the Centers for Disease Control and Prevention published Friday found that even patients with mild symptoms may develop chronic illness related to the disease. The CDC surveyed more than 270 symptomatic adults who tested positive for the virus between April 15 and June 25 but didn't need to be hospitalized. More than a third of those patients said they hadn't returned to their usual state of health two to three weeks after they were tested. Among young, previously healthy respondents — people ages 18 to 34 — the share of patients who hadn't recovered was nearly 20%. "Nonhospitalized COVID-19 illness can result in prolonged illness and persistent symptoms, even in young adults and persons with no or few chronic underlying medical conditions," the CDC researchers wrote. (more on the link) .