Fig. 3: Cumulative B. pertussis disease incidence in different aP-primed birth cohorts over time and impact of asymptomatic infection on mucosal antibody responses.

a Cumulative pertussis disease incidence for aP-primed birth cohorts including children born between 2007 and 2010 (red line) and between 2003 and 2006 (blue line), representing cohorts A and B, respectively. Pertussis disease incidence was obtained for postcode-matched regions where the vaccination study was conducted, covering the period from birth until the start of the BERT study. The solid lines reflect the cumulative pertussis disease incidence as the pertussis notifications/100,000 inhabitants. b MLF was obtained from adult volunteers prior to (day −7, baseline) and 28 days after intranasal inoculation with B. pertussis. Bp_mut, deficient for FHA, PRN, and PT, was incubated with heat-inactivated MLF and antibody binding was subsequently measured by flow cytometry. Log2-transformed mean fluorescence intensity (MFI) of IgA and IgG binding to Bp_mut. Data are N = 10. Sample means with 95% CI (solid black point and line) are plotted. Kruskal–Wallis followed by Wilcoxon signed-rank test was used to test significant differences over baseline in the controlled human infection study. **p ≤ 0.01, p = 0.0042 for IgA.