Data collection
Data was systematically reviewed by patient’s records: (a) demographics: age, sex, duration of signs/symptoms before diagnosis; (b) chronic conditions: pulmonary, neuropathies, cardiopathies, diabetes mellitus, systemic arterial hypertension, immunocompromising diseases [primary immunodeficiency, solid organ transplantation, hematopoietic stem cell transplant (HSCT), malignancies, chronic kidney disease, autoimmune diseases], and the use of immunosuppressive agent; (c) clinical features: fever, duration of fever, nasal discharge, sneezing, coughing, dyspnea, anosmia, pneumonia, myalgia, headache, conjunctivitis, rash, diarrhea, vomiting, abdominal, pain, neurological symptoms, seizure, SARS, hypoxemia and arterial hypotension; (d) laboratory parameters: hemoglobin concentration, leucocyte, lymphocyte and thrombocyte counts, C-reactive protein, fibrinogen, D-dimer, ferritin, lactate dehydrogenase; (e) radiological exams: thoracic radiography and computer tomography; (f) treatments: supplementary oxygen, antibiotics, oseltamivir, intravenous immunoglobulin, enoxaparin, aspirin, systemic glucocorticoids and dialysis; (g) and outcomes: hospitalization, admission in pediatric intensive care unit (PICU), duration of hospitalization, mechanical ventilation, vasoactive agents, shock, cardiac abnormalities, and death.