207221 - 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.

Study type

• Study topic:
  Disease /health condition

  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Safety study (incl. comparative)
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Name of medicine, other:
  Boostrix
• Medical condition to be studied:
  Pertussis

Population studied

• Short description of the study population:
  The exposed and unexposed cohorts will consist of pregnant women with evidence of prenatal care and continuous membership (allowing up to a 31-day gap) at KPSC between the 1st day of the 27th week of gestation and the index (vaccination) date. ; Women will be considered exposed if they received Boostrix on or after the 1st day of the 27 th week of gestation at selected ob-gyn clinics at seven medical centers throughout KPSC (vaccination period planned to begin in January 2018). Unexposed pregnant women comprise women pregnant sometime during the approximate estimated period between 1/1/2012 and 12/31/2013 who did not receive any Tdap vaccine during pregnancy. If needed, we will consider adding additional years to increase the eligible number of unexposed pregnant women. Gestational age will be estimated from the most reliable estimated date of delivery (EDD) which is based on the last menstrual period, the first accurate ultrasound examination, or both. Obstetric providers are recommended to reference guidelines from the American College of Obstetrics and Gynecology (ACOG) to calculate EDD. Pregnancy start date will correspond to a gestational age of 0 weeks
• Age groups:
  Adolescents (12 to < 18 years)

  Adults (18 to < 46 years)

  Adults (46 to < 65 years)
• Special population of interest:
  Pregnant women
• Estimated number of subjects:
  1

Study design details

• Main study objective:
  To rule out a two-fold increase in the incidence of each of the following maternal and infant AEs: preeclampsia and/or eclampsia, intra-uterine infections such as chorioamnionitis and endometritis, small for gestational age (SGA), and preterm delivery among women vaccinated with Boostrix as compared to a historical cohort of women who were unvaccinated with any Tdap vaccine during their pregnancy.
• Outcomes:
  Number of subjects with each of the following maternal and infant AEs:- Preeclampsia and/or eclampsia- Intra-uterine infections such as chorioamnionitis and endometritis- Small for gestational age (SGA)- Preterm deliveryMaternal and infant AEs are identified from KPSC's EHR system using the pregnancy episode flowsheet and diagnosis codes.
• Data analysis plan:
  For events identified any time after the index date and at delivery, crude incidence and 95% Confidence Interval(CI) for each AE for the exposed and unexposed groups will be calculated. The incidence of each maternal AE during pregnancy will be calculated separately and will consist of the total number of women with the condition in the numerator and the total person time in the denominator for the events identified any time after the index date, and for the events identified at delivery the incidence will consist of the total number of women with the condition in the numerator and the number of women for whom the condition can be assessed in the denominator. The person-year for a pregnant woman will be the time from the index date to the date of each adverse event, end of the pregnancy, or disenrollment, whichever comes first. The adjusted relative risk with CI will be estimated by aPoisson regression model accounting for the follow-up time with adjustment for potential confounders.

Documents

Study results

gsk-207221-clinical-study-report-redact-02