The Safety of Boostrix Following Routine Immunization of Pregnant Women

An Observational, Retrospective Cohort Database Study to Assess the Safety of Boostrix (U.S. Formulation), a Reduced Tetanus, Diphtheria, Acellular Pertussis Vaccine (Tdap), Following Routine Immunization of Pregnant Women in the United States

The purpose of this study was to assess the safety of Boostrix administered on or after the first day of the 27th week of pregnancy by conducting a post-marketing study that provided safety information to the public and healthcare providers. This was one of the largest cohorts of pregnant women vaccinated with Boostrix in the U.S. Through partnership between Kaiser Permanente Southern California (KPSC) and the sponsor, GlaxoSmithKline (GSK), information about the safety of maternal vaccination with Boostrix and maternal and infant adverse events (AEs) in a community setting was gained.

Inclusion Criteria:

• Pregnant women with prenatal care and continuous membership (allowing up to a 31-day gap) at KPSC between the 1st day of the 27th week of pregnancy and the index (vaccination) date.
• Exposed cohort (from the 27th week of gestation): Pregnant women vaccinated with Boostrix on or after the 1st day of the 27th week of pregnancy; who were not vaccinated with any other Tdap vaccine at any other time during the pregnancy in scope of this study.
• Unexposed cohort: Women matched to the exposed cohort and pregnant sometime during the approximate estimated period between January 1, 2012-December 31, 2014 and did not receive any Tdap vaccine during the pregnancy in scope of this study.

For the analysis of congenital anomalies among live births, at birth and through six months of age, the following additional inclusion criteria for infants will be applied:

• Live born
• Born in KPSC hospitals

Note: Pregnant women vaccinated with Boostrix during pregnancy before the 27th week of gestation, with membership at the date of vaccination, and who were not vaccinated with any other Tdap vaccine at any other time during the pregnancy in scope of this study will be part of a descriptive analysis (secondary objective).