1. Research Institute for Public Healthcare, National Medical Center, Seoul, Korea.
2. Department of Infectious Diseases, National Medical Center, Seoul, Korea.
3. Department of Pediatrics, National Medical Center, Seoul, Korea.
4. National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Korea.
5. Division of Infectious Diseases, VHS Medical Center, Seoul, Korea.
6. Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
7. Department of Internal Medicine, Jeonbuk National University Medical School, Jeonju, Korea.
8. Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea.