GSK Biologicals' rotavirus vaccine, Rotarix™ has been recommended for universal use targeting infants through the Expanded Program on Immunization (EPI) in Mexico. This protocol describes a Phase IV safety study in Mexico designed to further evaluate the safety profile of Rotarix™ with regard to intussusception (IS). The data generated by this study will be useful for public health officers and policy makers in confirming the safety profile of Rotarix™.