1. Department of Pediatrics, Korea University Guro Hospital, Seoul, Korea.
2. Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Infectious Disease Control, Bureau of Infectious Disease Policy, Korea Disease Control and Prevention Agency (KDCA), Cheongju, Korea.
4. Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Korea University Guro Hospital, Seoul, Korea.
5. Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.