Number of samples within each age-cohort, GMTs and seroprevalence of SBA (titers ≥8) in the pre- and post-MenC introduction eras.

aNumber between brackets is the number of samples included in the seroprevalence calculation (% samples≥8) and in not the GMT calculation, because only a SBA titer ≥16 could be given for these samples.*P-values calculated for differences between prevalence of SBA titers ≥8 pre- and post-MenC immunization with chi-square distribution, LR chi-square probability.**Calculated with Fishers exact t-test.GMT, geometric mean titer; NP, not possible; NA, not applicable; mo, age in months; y, age in years.