Fig. 3.

Severity of the COVID-19 symptoms in children (a) and adults (b). Symptoms were categorized as following: asymptomatic-no clinical signs or symptoms during the positive COVID-19 period; mild-symptoms of acute upper respiratory tract infection, including fever, fatigue, myalgia, cough, sore throat, runny nose, and sneezing or gastrointestinal symptoms or digestive symptoms such as nausea, vomiting, abdominal pain, and diarrhea; moderate-pneumonia with or without clinical symptoms, no hypoxia; severe-early respiratory symptoms or gastrointestinal symptoms followed by dyspnea and hypoxia (O₂ saturations <92%); critical-acute respiratory distress syndrome, respiratory failure, encephalopathy, shock, coagulopathy, multiorgan impairment (lung, heart, kidney, brain) that may be life threatening.