Rotavirus (RV) is the most important cause of acute gastroenteritis (GE) requiring hospitalization of infants and young children in developed and developing countries and can be a frequent cause of death in children less than 5 years of age. GSK Biologicals has developed a vaccine against human rotavirus gastroenteritis. In this study, the immunogenicity, reactogenicity and safety of the HRV vaccine will be evaluated when stored or reconstituted in circumstances different from the recommendations: i.e. when not reconstituted with a buffer or when stored for 7 days at 37°C before reconstitution. In addition, the effect of feeding will be explored for HRV vaccine reconstituted without buffer.