Figure 1.

Maternal vaccination with pertussis toxoid (PTx) vaccine does not reduce the bacterial burden in the airway of infants following infection with Bordetella pertussis. Infant baboons born to mothers vaccinated with the monocomponent PTx vaccine during pregnancy (blue; n = 4) or to unvaccinated mothers (black; n = 4) were directly challenged with B. pertussis at 5–6 weeks of age. Colonization was monitored by quantifying B. pertussis colony-forming units (CFUs) in nasopharyngeal washes, with a limit of detection of 10 CFUs/mL. Three of 4 infants born to unvaccinated mothers were euthanized owing to the severity of disease and were lost to follow-up.