Fig. 1: Flow diagram, study procedures, and humoral responses to Tdap-IPV vaccination.

In a phase IV multi-center clinical study conducted in the Netherlands (NL) and United Kingdom (UK), male and female adolescent participants between 11–15 years old who were primed in infancy with either an acellular (aP) or a whole-cell pertussis (wP) vaccine received a booster dose of tetanus-diphtheria-acellular pertussis-inactivated polio (Tdap-IPV). N = 14 participants (NL cohort) and N = 12 participants (UK cohort) were allocated for analysis of early post-vaccination immune responses. A Flow diagram of participants who were enrolled in the current study and analyzed. B Study design indicating blood sampling and analyses performed at each timepoint. Closed circles indicate measurements performed in both cohorts, and open circles indicate those performed only in the NL cohort. C Antibody response (log10 fold change of IgG concentrations vs baseline) for the specified Tdap antigens at 28 days and 1 year post-vaccination in the NL and UK cohorts. Data are N = 14 for the NL cohort and N = 12 in the UK cohort and are represented as box plots, with bounds from 25th to 75th percentile, median line, and whiskers, which extend to the largest or smallest value no further than 1.5 * the inter-quartile range. Statistical significance was determined using a two-sided paired Wilcoxon test, ** p < 0.01, *** p < 0.001. Nominal p values are reported. NL cohort: PT, p = 0.00012; FHA, 0.00012; Prn, p = 0.00012; Dt, p = 0.00012; TT, p = 0.0067. UK cohort: PT, p = 0.00049; FHA, 0.00049; Prn, p = 0.00049; Dt, p = 0.00049; TT, p = 0.00049. Abbreviations: FHA filamentous hemagglutinin, Prn pertactin, PT pertussis toxin, Dt diphtheria toxoid, TT tetanus toxin, F female, M male. Source data are provided in the Source Data file.