The main objectives of this study are: 1) In a subset (N = 20 000), to determine vaccine efficacy against severe rotavirus (RV) gastroenteritis (GE) during the period starting from 2 weeks after Dose 2 until one year of age. 2) In all subjects (N = 60 000), to determine the safety of GSK Biologicals' HRV vaccine with respect to definite intussusception (IS) within 31 days (Day 0-Day 30) after each HRV vaccine dose.