1. Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, Korea.
4. Department of Pediatrics, Inje University College of Medicine, Busan, Korea.
5. Department of Pediatrics, School of Medicine, Ajou University, Suwon, Korea.
6. Department of Pediatrics, Yonsei University Wonju College of Medicine, Wonju, Korea.
7. Division of Hepatitis and Enteric Viruses, Korea Centers for Disease Control and Prevention, Cheongwon, Korea.
8. Division of Epidemic Intelligence Service, Korea Centers for Disease Control and Prevention, Cheongwon, Korea.