Characteristics and clinical outcomes of COVID-19 in children: a hospital-based surveillance study in Latin America's hardest-hit city

•With no deaths, the study data contrast with the death rates reported in Brazil.•27.5% of hospitalized children were classified as severe/critical cases.•Most hospitalizations occurred in healthy children; risk was higher among those with comorbidities.•The leading determinants of hospitalization were pulmonary disease, cancer and obesity.•Children with multi-system inflammatory syndrome in this study had a lower median age compared with high-income countries. In 2020, Brazil became the epicentre of the coronavirus disease (COVID-19) pandemic in Latin America, resulting in an unparalleled health catastrophe. Nevertheless, comprehensive clinical reports in Brazilian children are not available. This retrospective, hospital-based, active surveillance study was performed to identify paediatric patients with COVID-19 who presented at a private academic medical centre in a large urban area between March 2020 and March 2021. Clinical and demographic information was analysed for those requiring hospitalization, those with severe illness and those with clinical syndromes. In total, 964 symptomatic cases were evaluated; of these, 17.7% required hospitalization, and 27.5% of hospitalized cases were classified as severe/critical. Acute bronchiolitis and pneumonia were the most common causes of hospitalization among the severe cases. Twenty-seven hospitalized children fulfilled the diagnostic criteria for multi-system inflammatory syndrome (median age 29 months; 85.2% cases were non-severe). A significant co-existing condition was present in 29% of hospitalized children. The risk of hospitalization was higher in children with at least one comorbidity, children aged