FIG 4.

Whole-cell pertussis vaccines reduce total nasopharyngeal B. pertussis burden. The total nasopharyngeal burden over the course of the infection was estimated by calculating the area under curve of the serial nasopharyngeal wash counts for each animal. The data are shown for each unvaccinated animal (n = 3), DTaP-vaccinated animal (n = 3), convalescent animal (n = 3), and each animal vaccinated with DTwP (Triple Antigen, DT-COQ, or Quinvaxem; n = 2 per group), with a bar representing the mean value for each group. *, P < 0.05 versus naive; **, P < 0.01 versus naive.