Table 1.

rSBA antibody persistence 1 month and 2 y after vaccination with MenACWY-TT or Men-PS at 11–17 y of age (According to protocol cohort as defined for each time point).

		MenACWY-TT						Men-PS
Sero group	Time point	N	n	% ≥1:8 [95% CI]	n	% ≥1:128 [95% CI]	GMT [95% CI]	N	n	% ≥1:8 % [95% CI]	n	% ≥1:128 [95% CI]	GMT [95% CI]
A	Pre*	557	463	83.1 [79.7; 86.1]	427	76.7 [72.9; 80.1]	208.1 [176.4; 245.5]	191	148	77.5 [70.9; 83.2]	128	67.0 [59.9; 73.6]	155.9 [113.8; 213.7]
	M1*	674	674	100 [99.5; 100]	674	100 [99.5; 100]	5928.5 [5557.4; 6324.3]	224	223	99.6 [97.5; 100]	223	99.6 [97.5; 100]	2947.2 [2611.7; 3325.7]
	Y2	405	404	99.8 [98.6; 100]	403	99.5 [98.2; 99.9]	1493.4 [1369.0; 1629.0]	132	132	100 [97.2; 100]	128	97.0 [92.4; 99.2]	780.3 [665.3; 915.2]
C	Pre*	648	381	58.8 [54.9; 62.6]	277	42.7 [38.9; 46.7]	44.1 [37.3; 52.2]	211	121	57.3 [50.4; 64.1]	79	37.4 [30.9; 44.3]	40.9 [30.2; 55.3]
	M1*	673	673	100 [99.5; 100]	672	99.9 [99.2; 100]	13109.8 [11939.1; 14395.2]	224	224	100 [98.4; 100]	223	99.6 [97.5; 100]	8222.0 [6807.5; 9930.4]
	Y2	407	404	99.3 [97.9; 99.8]	396	97.3 [95.2; 98.6]	1137.5 [1006.1; 1286.0]	132	131	99.2 [95.9; 100]	125	94.7 [89.4; 97.8]	1543.0 [1145.8; 2077.7]
W	Pre*	640	519	81.1 [77.8; 84.1]	373	58.3 [54.4; 62.1]	109.4 [94.6; 126.6]	216	176	81.5 [75.6; 86.4]	120	55.6 [48.7; 62.3]	112.2 [87.2; 144.3]
	M1*	678	677	99.9 [99.2; 100]	677	99.9 [99.2; 100]	8246.6 [7638.8; 8902.7]	224	224	100 [98.4; 100]	223	99.6 [97.5; 100]	2632.7 [2299.3; 3014.4]
	Y2	407	405	99.5 [98.2; 99.9]	403	99.0 [97.5; 99.7]	1977.6 [1775.0; 2203.4]	131	124	94.7 [89.3; 97.8]	113	86.3 [79.2; 91.6]	418.2 [317.6; 550.6]
Y	Pre*	659	597	90.6 [88.1; 92.7]	538	81.6 [78.5; 84.5]	348.3 [303.5; 399.7]	219	186	84.9 [79.5; 89.4]	167	76.3 [70.1; 81.7]	299.0 [225.2; 397.0]
	M1*	677	677	100 [99.5; 100]	677	100 [99.5; 100]	14086.5 [13168.0; 15069.0]	224	224	100 [98.4; 100]	224	100 [98.4; 100]	5066.3 [4463.1; 5750.9]
	Y2	407	407	100 [99.1; 100]	407	100 [99.1; 100]	3502.5 [3203.2; 3829.7]	130	126	96.9 [92.3; 99.2]	123	94.6 [89.2; 97.8]	1028.3 [797.3; 1326.1]

Pre = prior to vaccination at 11–17 y of age; M1 = 1 month after vaccination; Y2 = 2 y after vaccination; N = number of subjects with available results; n/% = number/percentage of subjects with titer equal to or above specified value; 95% CI = 95% confidence interval; GMT = geometric mean antibody titer; rSBA = serum bactericidal activity against N. meningitidis using rabbit complement, performed at GSK Vaccines' laboratories;

bold = statistically higher proportion of subjects reaching the indicated threshold, or higher GMT value (adjusted for pre-vaccination measurements and age strata for M1 results) in the indicated group (exploratory analysis).

^*This table reports the results of the re-analysis of data after elimination of subjects due to GCP violations.

Note: the discrepancy in the numbers of subjects in pre and post-vaccination samples is mainly due to a high number ‘invalid results’ at pre-vaccination time point. A result was considered invalid when an irregular pattern of the killing curve was observed between 60% and 40% of killing. During this study, process changes in the testing laboratory meant that samples were automatically repeat-tested. However numerous invalid results occurred in the low range of titres affecting repeat tested pre-vaccination samples more than post-vaccination samples. As indicated in this table, the results provided at each time point are from the “According to protocol cohort as defined for each time point.” N for Pre and M1 includes subjects from the ATP immunogenicity cohort from the vaccination study, and N for Y2 includes ATP persistence cohort subjects who returned at y 2. Fewer subjects returned for follow-up 2 y after the initial study, resulting a lower N at y 2.