Table 7.

Comparison of DTaP and DTP Vaccine Efficacy as Analyzed in the Cohort Study and the Household Contact Study With Exclusion of Noncases Who Received Macrolide Antibiotics or Trimethoprim-Sulfamethoxazole During the Exposure Period in the Household Contact Study (7–42 Days)

Efficacy AgainstCohort StudyHousehold Contact Study
DTP Vaccine Efficacy, %
(95% CI)
DTaP Vaccine Efficacy, %
(95% CI)
DTP Vaccine Efficacy, %
(95% CI)
DTaP Vaccine Efficacy, %
(95% CI)
 I) Mild and typical pertussis
B pertussisspecific*83 (76–88)72 (62–79)84 (65–93)58 (30–75)
B pertussis or any serologic  evidence66 (56–74)63 (53–71)70 (48–83)51 (22–69)
II) Typical pertussis
B pertussisspecific93 (89–96)83 (76–88)94 (77–99)86 (62–95)
B pertussis or any serologic  evidence§84 (77–89)79 (72–85)94 (77–99)84 (61–93)
  • Abbreviations: DTP, diphtheria-tetanus toxoids; whole cell pertussis vaccine, adsorbed, DTaP, diphtheria-tetanus toxoids, acellular pertussis vaccine, adsorbed; PCR, polymerase chain reaction.

  • * Principal efficacy analysis in both studies requiring ≥7 days of cough and isolation of B pertussis or significant antibody response to pertussis toxin.

  • Ancillary I case definition for primary and secondary cases in the household contact study requiring ≥7 days of cough and isolation ofB pertussis or significant antibody response to any B pertussis antigen or significant agglutinin response; similar case definition in the cohort study except PCR.

  • Principal case definition for the primary case and ancillary II case definition for the secondary case in the household contact study requiring ≥21 days of cough with either paroxysms, whoop, or vomiting and isolation of B pertussis or significant antibody response to pertussis toxin; identical case definition in the cohort study.

  • § Ancillary I case definition for the primary case and ancillary III case definition for the secondary case in the household contact study requiring ≥21 days of cough with either paroxysms, whoop, or vomiting and isolation of B pertussis or significant antibody response to any B pertussis antigen or significant agglutinin response; identical case definition in the cohort study.