A national prospective cohort study of COVID-19 in children referred to hospitals. All patients under the age of 18 who present to participating hospitals with suspected COVID-19 may be included. Patients with confirmed COVID-19 will be compared to patients with disproved COVID-19. We will use WHO's ISARIC model protocol, developed specifically for such pandemics. We will record epidemiological risk factors, symptoms, clinical findings, results of blood tests, X-rays and other investigations, treatment measures, complications, mortality and measures at the hospital to prevent the spread of infection. Patients are summoned for follow-up examinations 2 and 6 months after the outbreak of illness. Biological material for biobanking is taken at all time points. Patients over the age of 10 will also fill out a questionnaire on inclusion and follow-up. The questionnaire includes questions about fatigue, as well as psychosocial conditions. Data from various Norwegian patient and quality registries will be sought to strengthen the study.