Table 3.

DTaP and DTP Vaccine Efficacy Against Cough Illness of ≥7 Days Duration as a Result of Bordetella pertussis Infection Using the Principal Efficacy Analysis Case Definitions*

VaccineNo. Cases/
No. Exposed
(Attack Rate)
%
Vaccine
Efficacy
95%
Confidence
Interval
7 to 28 Day Postexposure Observation Period
 DT11/34 (32%)
 DTP 6/65 (9%)7130–88
 DTaP12/61 (20%)39−23–70
7 to 42 Day Postexposure Observation Period
 DT16/34 (47%)
 DTP 6/65 (9%)8054–92
 DTaP13/61 (21%)5518–75
  • Abbreviations: DTaP, diphtheria-tetanus toxoids, acellular pertussis vaccine, adsorbed; DTP, diphtheria-tetanus toxoids, whole cell pertussis vaccine, adsorbed; DT, diphtheria-tetanus toxoids vaccine.

  • * See Table 1.