Effectiveness of Monovalent Rotavirus Vaccine (RV1)

Inclusion Criteria: * the child is \< 6 years of age * for the vaccine effectiveness analysis using the Minimum Age Model, the child was included if born on or after 8/10/2008 at MUSC and on or after 12/1/2008 at CCHMC. * for the vaccine effectiveness analysis using the Maximum Age Model, the child was included if \>=8 months of age. * the child is being evaluated at Cincinnati Children's Hospital Medical Center (CCHMC) or the Medical University of South Carolina (MUSC) as an inpatient, short-stay visit or in the emergency department * the child has acute gastroenteritis defined as * diarrhea (\>3 loose stools in a 24 hour period) OR * -vomiting (\>1 episodes in a 24 hour period) * the child's illness is of \<10 days duration * written consent is obtained from the child's parent or legal guardian Exclusion Criteria: * the child is \>6 year of age * the child had onset of fever or gastroenteritis symptoms \> 10 days prior to admission * the child has a non-infectious or other identifiable cause of their symptoms, such as head trauma, pyelonephritis, pyloric stenosis, or prolonged coughing * the child is immunocompromised * there is no parent or guardian available * the parent/guardian is non-English speaking * previously enrolled for the same episode of gastroenteritis * for the vaccine effectiveness analysis using the Minimum Age Model, the child was excluded if born prior to 8/10/2008 at MUSC and prior to 12/1/2008 at CCHMC. * for the vaccine effectiveness analysis usi…