1. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Yonsei University College of Medicine, Gangnam Severance Hospital, Seoul, Korea.
3. Department of Laboratory Medicine, Chonnam National University Hwasun Hospital, Hwasun, Korea.
4. Molecular Epidemiology and Bioinformatics Laboratory, Division of Viral Hepatitis, Center for Disease Control and Prevention, Atlanta, GA, USA.