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™.

Rationale for amendment 3:

The findings from the first year of the implementation of the active surveillance showed that most Lower Respiratory Tract-Related Post-Neonatal (LRTI) Mortality cases could not be included into the study, because most of the grieving parents refused to participate in the study. The European Medicines Agency Marketing Authorization Holders (EMEA MAH) also generated a substantial amount of additional clinical and post-marketing safety data throughout the world, which clearly indicated the absence of any safety signal when considering the LTRI-related fatalities. Therefore surveillance for LRTI mortality cases was removed from the study design. The number of sites was reduced from approximately 230 to about 60 to 90 in order to reflect the above mentioned change that reduced the need for so many sites. Additionally, passive surveillance for IS cases through the IMSS database was not feasible, due to restrictions of the IMSS internal policies and to the current limitations in the databases linkage and structure abilities.

Lastly, SAEs reporting procedures had to be adjusted according to the Council for International Organizations of Medical Sciences (CIOMS) Working Group V, 2001 publication such that there will be no expedited safety reporting for this study.

Design This is a post marketing ,Phase IV, observational, prospective, self-controlled case series, vaccine safety study including: a) hospital-based surveillance to monitor for the occurrence of IS through active surveillance; b) a self-controlled case series (SCCS) design/analysis to assess the temporal association with Rotarix™ of the IS ascertained through active surveillance.

The aim of the active hospital-based surveillance system is to identify all definite IS cases in children younger than one year of age (children ineligible on day of first birthday) among IMSS members. Surveillance will be conducted in approximately 60 to 90 IMSS health facilities with pediatric surgery service.

Study participation for children fitting the surveillance case definition of IS will include parental/guardian/legal representative interview, as well as a review of medical charts and vaccination records. Additional medical information will be collected through medical record review during hospitalization and after the child has been discharged.

Inclusion Criteria:

A child's clinical episode will be defined as an IS case and deemed eligible for the study if he/she meets the following criteria:

• Subject is an IMSS affiliate
• Subject is being treated/has been treated/has been referred for treatment at one of the IMSS hospitals/medical facilities with IS during the study period.
• Male or female child is \

All eligible children < 1 year of age (children ineligible on day of first birthday) who are/have been treated at one of the study hospitals/medical facilities with definite intussusception.