1. Division of Pulmonary Medicine, Department of Internal Medicine, Hallym University Hangang Sacred Heart Hospital, Seoul
2. Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangnam Sacred Heart Hospital, Seoul
3. Infection Control Team, Hallym University Hangang Sacred Heart Hospital, Seoul
4. Division of Pulmonary Medicine and Allergy, Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea