Table 2.

Preimmunization and Postimmunization Geometric Mean Antibodies (95% CI) and Antibody Response Rates of Groups Receiving dTpa or Td + pa*

VariableVaccine Group
dTpa (n = 447)Td (n = 57)pa (n = 57)
Pertussis toxin
 Pre-GMV(EU/mL)10 (8–11)10 (6–14)8 (6–12)
 Post-GMV118 (105–131)8 (6–12)158 (121–206)
 Response (%) 92  0 96
Filamentous hemagglutinin
 Pre-GMV (EU/mL)58 (52–66)60 (41–86)53 (36–77)
 Post-GMV923 (852–1000)53 (36–77)1106 (857–1427)
 Response (%) 97  0 98
Pertactin
 Pre-GMV (EU/mL)18 (15–20)17 (11–28)18 (11–30)
 Post-GMV595 (520–680)18 (11–30)823 (570–1188)
 Response (%) 99  0100
Diphtheria toxoid
 Pre-GMV (IU/mL).2 (.2–.2).2 (.1–.2)8 (6–10)
 Post-GMV7 (6–8)8 (6–10)6 (5–8)
 ≥.1 IU/mL (%)1001000
Tetanus toxoid
 Pre-GMV (IU/mL).5 (.5–.6).5 (.4–.7)38 (31–46)
 Post-GMV24 (23–26)§38 (31–46)§28 (23–33)
 ≥.1 IU/mL (%)1001000
  • * The pa vaccine was given 1 month after the Td vaccine to the same subjects.

  • Pre-GMV indicates preimmunization geometric mean antibody value.

  • A positive antibody response to pertussis antigens was defined as seroconversion for initially seronegative subjects or a minimum of twofold increase in antibody values for initially seropositive subjects.

  • § P < .001 between dTpa and Td groups.