Study to Evaluate the Effectiveness of Rotarix™ Against Severe Gastroenteritis Among Hospitalized Children in Brazil

Inclusion Criteria: For cases: * A male or female child born after 6 March 2006 and at least 12 weeks of age. * Subject admitted to the study clinics/hospitals for severe gastroenteritis during the study period. * Onset of severe gastroenteritis ≤ 14 days prior to admission. * Laboratory confirmed rotavirus positive stool sample at hospital admission or during the first 48 hours of hospitalization. * Written informed consent obtained from the parent or guardian of the subject. For controls: * Admitted for non-gastroenteritis causes at the same clinic/hospital as the case. * Living in the same neighbourhood as the case for at least three consecutive months without any symptoms of gastroenteritis or severe gastroenteritis on the day of interview of his/ her parents/ guardians. * Being born within +- 2 weeks from the date of birth of the case. If the number required is not available, then the range would be extended to +- 4 weeks, and ultimately up to +- 6 weeks for hospital controls. For neighbourhood controls, the range may be extended to +- 8 weeks. * Written informed consent obtained from the parent or guardian of the child. Exclusion Criteria: For cases: * Subject has previously participated as case or control in this study. * Onset of severe gastroenteritis \> 48 hours after admission to the hospital (nosocomial infections). For controls: * For hospital controls: Child who has symptoms of gastroenteritis during current hospitalization or on the day of interview of his/her parent or guardian or for neighbourhood controls: Child who has symptoms of gastroenteritis or severe gastroenteritis on the day of interview of his/her parent or guardian. * Exclude children with the following vaccine preventable diseases: measles, mumps, rubella, diphtheria, pertussis, tetanus, tuberculosis, invasive Haemophilus influenzae type B (Hib) infections (meningitis, bacteraemia, septic arthritis, cellulitis, and epiglottitis) and hepatitis B. * Child has participated in the past as a case or control in this study. * Child living in the same house as the case