1. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
2. Research Institute of Emerging Infectious Disease, Korea University College of Medicine, Seoul, Korea.
3. Department of Pulmonology and Critical Care Medicine, Ajou University School of Medicine, Suwon, Korea.
4. Department of Internal Medicine, Hallym University College of Medicine, Chuncheon, Korea.
5. Department of Internal Medicine, Gachon Medical School, Incheon, Korea.
6. Department of Internal Medicine, Inha University College of Medicine, Incheon, Korea.