Effectiveness of Adacel Vaccination in Pregnancy at Preventing Pertussis in Infants < 2 Months of Age in the United States

Inclusion Criteria: Cases were included if they met the following inclusion criteria: * Reported pertussis disease in the referenced EIP surveillance database * Age greater than 2 days and younger than two months of age * Resided in the catchment area on date of onset of their cough * Born in a hospital in their state of residence * ≥ 37 weeks of gestation at birth * Not adopted, in foster care or living in a residential care facility * Completed maternal interview * Completed infant and maternal information Controls were included if they met the following inclusion criteria: * Age greater than 2 days and younger than 2 months of age on date of cough onset for the corresponding case infant * Resided in the catchment area on date of cough onset for the corresponding case infant * Born in a hospital in their state of residence * ≥ 37 weeks of gestation at birth * Not adopted, in foster care or living in a residential care facility * Maternal interview completed * Infant and maternal information complete Exclusion Criteria: Cases were excluded if they met any of the following exclusion criteria: * Vaccination status of the mother unknown * Infants whose mothers were vaccinated with Boostrix or an unknown vaccine brand Controls were excluded if they met any of the following exclusion criteria: * Vaccination status of the mother unknown * A pertussis diagnosis prior to the cough onset date of the corresponding case infant * Controls that were matched to Boostrix or an unknown brand cases