1. Seoul Center for Infectious Disease Control, Seoul, Korea.
2. Department of Epidemiology, Graduate School of Public Health, Seoul National University, Seoul, Korea.
3. Institute of Endemic Disease, Seoul National University College of Medicine, Seoul, Korea.
4. Division of Infectious Diseases, Seoul National University Boramae Medical Center, Seoul, Korea.
5. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
6. Department of Family Medicine, Seoul National University College of Medicine, Seoul, Korea.