Department of Pediatric Infectious Diseases and Immunology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. Advanced Interdisciplinary Rehabilitation Register (AIRR) - COVID-19 Working Group, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. Division of Pediatrics, Pontificia Universidad Católica de Chile, Hospital Clínico Red Salud UC-Christus, Santiago, Chile. Department of Pediatrics, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. Division of Pediatrics, Pontificia Universidad Católica de Chile, Hospital Dr. Sótero del Río, Santiago, Chile. Centro de Responsabilidad de Peditaría, Hospital Clínico La Florida, Santiago, Chile. Department of Pediatric Gastroenterology and Nutrition, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. Department of Pediatric Gastroenterology and Nutrition, School of Medicine, Pontificia Universidad Catolica de Chile, Hospital Josefina Martínez, Santiago, Chile. Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.