Long COVID or long-haul COVID is a condition characterized by long-term health problems persisting or appearing after the typical recovery period of COVID-19. Although studies into long COVID are under way, as of May 2022 there is no consensus on the definition of the term. Long COVID may affect multiple organ systems, including disorders of the respiratory, cardiovascular, gastrointestinal and nervous systems, mental health, metabolism, musculoskeletal pain, and anemia. The most commonly reported symptoms of long COVID are fatigue and memory problems. Many other symptoms have also been reported, including malaise, headaches, shortness of breath, anosmia, parosmia, ageusia, muscle weakness, low-grade fever, and cognitive dysfunction. Estimates of the prevalence of long COVID vary based on definition, population studied, time period studied, and methodology, generally ranging between 5% and 50%.