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

The original study included cases recorded from 01 January 2011 through 31 December 2014, based on retrospective case-control methodology.

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