1. Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
2. Division of Infectious Disease, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
3. Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine and AIDS Research Institute, Yonsei University College of Medicine, Seoul, Korea.
5. Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, Korea.
6. Division of Viral Disease Research Center for Infectious Disease Research, Korea National Institute of Health, Cheongju, Korea.