Mean change in antimeningococcal IgG geometric mean concentrations and rSBA geometric mean titers from baseline to postvaccination per vaccine groupa

Vaccine groupNo. of subjectsIgG GMC (μg/ml)rSBA GMT
Serogroup CSerogroup YSerogroup CSerogroup Y
BaselinePost-vaxMean changeBaselinePost-vaxMean changeBaselinePost-vaxMean changeBaselinePost-vaxMean change
Group 1 (ref group), MenACWY only410.
Group 2, Plus Tdap only240.032.2282.32.0935.7217.14.221284.65304.221.46632.1629.5
Group 3, Plus 4, not Tdap/IPV1050.030.6621.91.3214.0210.710.98348.6434.417.28436.2925.4
Group 4, Plus 4, not Tdap1500.041.2833.01.2114.9712.44.12392.4395.823.431036.9244.7
P valueb0.0030.016c0.0010.002
  • a Abbreviations: GMC, geometric mean concentration (μg/ml); GMT, geometric mean titer; IgG, immunoglobulin G; IPV, inactivated polio vaccine; MenACWY, tetravalent meningococcal conjugate vaccine A, C, W, and Y; Post-vax, postvaccination; rSBA, rabbit complement serum bactericidal antibody assay; ref, reference; Tdap, tetanus-diphtheria-acellular pertussis vaccine.

  • b Kruskal-Wallis P values were calculated for testing the null hypothesis that the distribution of values across the four vaccine groups was the same.

  • c This P value is not statistically significant with a Bonferroni adjustment to the alpha level of 0.0125.