Table 2. Geometric Mean Titers (GMTs) of Meningococcal Serogroup C (MenC) Specific Serum Bactericidal Antibody (SBA) and Proportion of Participants with an SBA titer ≥8 and ≥128 prior to (T0) and 1 Month (T1) and 1 Year (T2) after the MenC Conjugate Booster.

			Age at T0		P-value difference between groups*
		10 years	12 years	15 years	10 vs.12	10 vs. 15	12 vs. 15
T0	GMT (95%CI)	4.0 (2.9–5.4)	8.2 (5.3–12.6)	13.1 (8.1–21.0)	0.006	<0.001	0.459
	SBA ≥8: proportion	17/91	31/91	39/86
	SBA ≥8: % (95%CI)	19 (12–28)	34 (25–45)	45 (35–56)	0.057	<0.001	0.375
	SBA ≥128: proportion	6/91	16/91	23/91
	SBA ≥128: % (95%CI)	7 (3–14)	18 (11–27)	27 (18–37)	0.069	<0.001	0.426
T1	GMT (95%CI)	31,564 (26,899–37,038)	45,175 (38,608–52,859)	47,289 (40,422–55,322)	0.021	0.003	1.000
	SBA ≥8: proportion	88/88	89/89	85/85
	SBA ≥8: % (95%CI)	100 (95–100)	100 (95–100)	100 (95–100)	1.000	1.000	1.000
	SBA ≥128: proportion	88/88	89/89	85/85
	SBA ≥128: % (95%CI)	100 (95–100)	100 (95–100)	100 (95–100)	1.000	1.000	1.000
T2	GMT (95%CI)	1,987 (1,602–2,247)	4,165 (3,444–5,038)	6,292 (5,272–7,509)	<0.001	<0.001	0.021
	SBA ≥8: proportion	85/85	89/89	83/83
	SBA ≥8: % (95%CI)	100 (95–100)	100 (95–100)	100 (95–100)	1.000	1.000	1.000
	SBA ≥128: proportion	85/85	89/89	83/83
	SBA ≥128: % (95%CI)	100 (95–100)	100 (95–100)	100 (95–100)	1.000	1.000	1.000

NOTE: Differences between groups in SBA GMTs at T0 were determined using the Mann-Whitney U test. Differences between groups in SBA GMTs at T1 and T2 were determined with linear regression analyses, adjusting for titers at T0. An SBA titer ≥8 was considered as international correlate of protection. Differences between groups in proportion of participants with an SBA titer ≥8 and ≥128 was determined with χ²-tests.

* 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.