FIGURE 3.

Effect of 2-dose schedules including neonatal immunization on protection of offspring against B. pertussis infection. (A) Schematic representation of vaccination and challenge protocols. Seven-day-old neonatal mice were vaccinated with a commercial aP, OMVP, or a commercial wP vaccine (n = 8 in each group). The second dose, involving a different type of vaccine from the first, was administered 14 days after the first dose. Non-immunized and aP-aP–immunized mice were used as respective negative and positive controls of protection. All the mice were then challenged with B. pertussis at 35 days after birth followed by sacrifice at 42 days. (B) Protection of offspring through the vaccination schedules of (A). The number of bacteria recovered from mouse lungs, expressed as the log₁₀ of the CFUs per lung, is plotted on the ordinate for the combination of vaccine types indicated on the abscissa, with the data representing the means ± the SD. The dotted horizontal line demarcates the lower limit of detection. ^∗∗∗p < 0.001, ^∗∗p < 0.05.