Figure 1.

(A) Demonstration of waning immunity following either infant/early childhood diphtheria, tetanus, and acellular pertussis (DTaP) or early adolescent tetanus, reduced diphtheria, and acellular pertussis (TdaP), measured as vaccine effectiveness. Vaccine effectiveness was calculated in each study as described in Table 1. The California five-dose study refers to Misegades et al. (2012), whereas the TdaP study refers to Klein et al. (2016). *Last point is 24–47 mo post-booster. (B) Demonstration of waning immunity with DTaP measured as relative risk (RR) of infection, with regard to first-year post-booster vaccination.