Table 4. Geometric Mean Concentrations (GMCs) of Meningococcal Serogroup C Polysaccharide (MenC-PS) Specific Immunoglobulin G (IgG) Subclass and Subclass Ratio.
| Age at T0 | P-value difference between groups* | ||||||
| 10 years | 12 years | 15 years | 10 vs. 12 | 10 vs. 15 | 12 vs. 15 | ||
| T0 | No. analyzed | 91 | 91 | 86 | |||
| GMC IgG1 µg/mL (95%CI) | 0.34 (0.29–0.41) | 0.34 (0.27–0.44) | 0.34 (0.27–0.43) | 1.000 | 1.000 | 1.000 | |
| GMC IgG2 µg/mL (95%CI) | 0.09 (0.08–0.11)a | 0.13 (0.11–0.17)b | 0.16 (0.12–0.21) | 0.024 | 0.003 | 1.000 | |
| IgG1/IgG2 | 3.98 (3.23–4.91)a | 2.71 (2.23–3.30)b | 2.17 (1.68–2.79) | 0.027 | <0.001 | 0.522 | |
| T1 | No. analyzed | 88 | 90 | 85 | |||
| GMC IgG1 µg/mL (95%CI) | 158.6 (138.2–181.9) | 213.4 (183.4–248.3) | 168.7 (139.5–203.9) | 0.015 | 1.000 | 0.174 | |
| GMC IgG2 µg/mL (95%CI) | 14.0 (11.1–17.7) | 28.0 (23.3–33.6) | 30.5 (23.9–38.9) | 0.003 | <0.001 | 1.000 | |
| IgG1/IgG2 | 11.30 (9.44–13.51) | 7.59 (6.40–9.00) | 5.54 (4.31–7.10) | 0.255 | 0.054 | 0.276 | |
| T2 | No. analyzed | 85 | 89 | 83 | |||
| GMC IgG1 µg/mL (95%CI) | 13.21 (11.32–15.42) | 22.22 (18.51–26.68) | 26.29 (22.39–30.88) | <0.001 | <0.001 | 0.531 | |
| GMC IgG2 µg/mL (95%CI) | 1.28 (1.02–1.59) | 3.23 (2.54–4.12) | 5.32 (3.99–7.10) | <0.001 | <0.001 | 0.09 | |
| IgG1/IgG2 | 10.36 (8.36–12.84) | 6.87 (5.61–8.42) | 4.94 (3.73–6.55) | 0.969 | 0.156 | 0.297 | |
NOTE: Differences between age groups in GMC of MenC-PS specific IgG subclass and subclass ratio were determined with linear regression analyses, adjusting for concentrations and ratios at T0.
* P-values were adjusted for three comparisons with Bonferroni correction. Extensive results of the crude and adjusted linear regression analyses are outlined in supplementary table S1.
a. Concentration IgG2 too low to measure in nine participants; GMC IgG2 and subclass ratio presented from 82 participants.
b. Concentration IgG2 too low to measure in five participants; GMC IgG2 and subclass ratio presented from 86 participants.