1. Department of Internal Medicine, Incheon Medical Center, Incheon, Korea.
2. Infection Control Office, Incheon Medical Center, Incheon, Korea.
3. Designated Isolation Unit, Incheon Medical Center, Incheon, Korea.
4. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
5. Department of Radiology, Incheon Medical Center, Incheon, Korea.