TABLE 4

Numbers and percentages of subjects in each vaccine group who were below the IgG and rSBA immunologic thresholds at baseline and at or above the thresholds postvaccinationa

Assay and vaccine groupSerogroup CSerogroup Y
nbAT nAT%OR95% CIP valuecnbAT nAT%OR95% CIP valuec
IgG
    Group 1 (ref group), MenACWY only338241.00 (ref)0.0072310431.00 (ref)<0.001
    Group 2, Plus Tdap only2215686.72.0–220.002108805.20.9–300.066
    Group 3, Plus 4, not Tdap/IPV9029321.50.6–3.70.3945036723.31.2–9.40.022
    Group 4, Plus 4, not Tdap13356422.31.0–5.40.064797190123.8–35<0.001
rSBA
    Group 1 (ref group), MenACWY only3014471.00 (ref)0.001179531.00 (ref)0.114
    Group 2, Plus Tdap only201995222.6–1830.0051410712.20.5–1.00.297
    Group 3, Plus 4, not Tdap/IPV6550773.81.5–9.60.0046047783.21.0–100.043
    Group 4, Plus 4, not Tdap11692794.41.9–100.0017964813.81.3–110.018
  • a Unadjusted logistic regressions with odds ratios are shown for the association of the MenACWY-only group and each of the other vaccine groups. Significant P values are in bold; the alpha was 0.05 for the significance of the parameter values within each model. Abbreviations: AT n and AT%, number and percentage, respectively, of subjects who were below the immunologic threshold at baseline and at or above the threshold postvaccination; CI, confidence interval; IgG, immunoglobulin G; IPV, inactivated polio vaccine; MenACWY, tetravalent meningococcal conjugate vaccine A, C, W, and Y; OR, odds ratio; rSBA, rabbit complement serum bactericidal assay; ref, reference; Tdap, tetanus-diphtheria-acellular pertussis vaccine.

  • b n includes only subjects with baseline concentrations/titers below immunologic thresholds. The immunologic threshold was defined as a change in IgG concentration of ≥2 μg/ml or rSBA titer of ≥8.

  • c Overall P value for the variable “vaccine group.” This tested the null hypothesis that vaccine group was a significant predictor of change in attaining threshold. The alpha was adjusted to 0.0125 to account for the four hypothesis tests.