With more adolescents and young adults being treated for COVID-19, clinicians are concerned that these people also will start showing post-COVID—or “long haul”—symptoms from their bouts with the virus. A recent Johns Hopkins Medicine review of three case studies provides some of the first evidence that one serious post-COVID problem may be myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), the complex, multisystem disorder previously known as chronic fatigue syndrome.