1. Vaccine Bio Research Institute, The Catholic University of Korea, Seoul, Republic of Korea.
2. Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, Republic of Korea.
3. Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
4. Department of Infectious Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
5. GlaxoSmithKline Biologicals, Seoul, Republic of Korea.