Information has been received from the author of a literature article concerning an infant who on an unspecified date received partial vaccination (a valid dose) with ROTATEQ (lot number unknown). This was part of a matched case control study that was performed by using a city state population bases immunization information systems (IIS) to calculate rotavirus vaccine effectiveness (VE) against hospitalization; results were compared with pre-licensure efficacy and with estimates previously obtained by traditional care-control methods using the matched controls from medical sources and medical chart abstracted data. Case-patients were all infants aged more or equal than 2 months but less than 3 years who had a positive stool test for rotavirus antigen and were hospitalized (admitted as inpatients) for gastroenteritis any time during July 2006 to December 2008. Age 2 months was chosen because rotavirus vaccination is recommended to begin at that age. The upper age limit was the oldest a child could who had received at least one dose of vaccine by July 2006. Because rotavirus was not a reportable disease in the city at the time of this study, cases were identified through a retrospective review of hospital laboratory data beginning in July 2006, when ROTATEQ began to be widely distributed throughout the state. Medical charts of all case-patients were reviewed by the study investigators to confirm that clinical symptoms were compatible with rotavirus gastroenteritis. Using an immunization registry and tracking system five control subjects were matched to each case patient by birth date (within 14 days) and town of residence. After matching by town, control subjects were selected using the closest qualifying matches by birth date. In addition, based on review of the hospitals laboratory data, controls had not been hospitalized for a laboratory confirmed rotavirus infection during July 2006 to 31-DEC-2008. Control subjects were not contacted to verify absence of rotavirus infection diagnosed elsewhere. Rotavirus vaccination status for case-patients and control subjects was obtained directly from the immunization registry and tracking system. The immunization registry and tracking system record of case-patients was identified by searching for an exact match of first and last names and birth date. For the subset of case patients and matched subjects, the number of rotavirus vaccine doses and exact dates of administration were extracted. A dose of rotavirus vaccine was considered valid if administered at least 7 days before illness onset of the case-patient. Additionally, a dose was considered valid if administered at age-appropriate intervals according to 2006 national recommendations. The majority of the study period occurred before national recommendations were updated in June 2008 to increase the maximum age for the first dose and to extend the interval between subsequent dosing. Case-patients without a immunization registry   [Due to memory limitations, the remainder of this text could not be compared.]  gistry and tracking system record (no matching name and birth date) were excluded from analysis. Descriptive statistics were used to summarized rotavirus immunization information (vaccination with ROTATEQ). This case pertains to an infant who during July 2006 to December 2008 presented a case of rotavirus gastroenteritis and was hospitalized. The patient had a positive stool test for rotavirus antigen. At the time of the report the patient's outcome was unknown. The authors considered that rotavirus gastroenteritis was related to ROTATEQ. This is one of several reports received from the same source. Additional information has been requested.