Post-marketing Safety Study of GSK Biological's Pediarix™ Vaccine

Inclusion criteria: Primary study cohort The primary study cohort will include all infants from SCKP who have begun their primary course of vaccine with PEDIARIX co-administered with Prevnar and for whom at least one dose of PEDIARIX was administered prior to the infant's 9-month birthday and safety follow-up information is available. Control cohorts Three control cohorts will be evaluated. 1. The historical cohort will include age-, gender- and area-matched infants from SCKP who received at least one dose of DTaP vaccine co-administered with Prevnar prior to the infant's 9-month birthday and for whom safety follow-up information is available. This cohort will include infants vaccinated between January, 2002 and March, 2003. 2. The self-control cohort is defined for the study subject as the 20-day post-vaccination period from Day 21 to Day 41 for each infant in the primary cohort (PEDIARIX co-administered with Prevnar as the primary vaccination course). 3. The "delayed PEDIARIX use clinic" cohort will include all infants from SCKP who, during the enrollment period for the primary cohort, began their primary course of vaccination with DTaP vaccine and for whom at least one dose of DTaP vaccine was co-administered with Prevnar prior to the infant's 9-month birthday and safety follow-up information is available. The size of this cohort will depend on how quickly individual SCKP clinics and medical centers use PEDIARIX once it is made available. The size of this cohort, therefore, is not immediately predictable. Exclusion Criteria: none