Table 4.

 Multiple regression analysis for meningococcal serogroup C specific serum bactericidal antibody geometric mean titres and IgG geometric mean concentrations after immunisation with Menjugate at ages 6-7, 8, 9, 10, and 11 years, compared with immunisation at 12-15 years

Age at immunisation (years)	Estimated relative difference* (robust 95% CI)	P value
Serum bactericidal antibody geometric mean titres
Overall	–	<0.001
6-7	0.28 (0.12 to 0.66)	0.005
8	0.23 (0.10 to 0.52)	0.001
9	0.27 (0.11 to 0.69)	0.01
10	0.73 (0.32 to 1.71)	0.4
11	0.84 (0.51 to 1.37)	0.5
12-15	Reference	–
IgG geometric mean concentrations
Overall	–	<0.001
6-7	0.26 (0.14 to 0.47)	<0.001
8	0.42 (0.27 to 0.65)	<0.001
9	0.48 (0.30 to 0.75)	0.002
10	0.70 (0.41 to 1.21)	0.2
11	0.90 (0.62 to 1.29)	0.5
12-15	Reference	–

*Adjusted for sex, years since immunisation, batch of Menjugate received, and clustering effect of school/campus attended.