Table 2.

Immune response as determined by haemagglutinin inhibition (HI) and neutralising antibody titres in Study A and in Study B (ATP cohort for persistence at Month 12)

		Study A		Study B
				3–9 years age group		10–17 years age group
HI responses		N		N		N
SPR [95% CI]	Day 0	88	3.4 [0.7–9.6]	92	3.3 [0.7–9.2]	87	13.8 [7.3–22.9]
	Day 21	87	100 [95.8–100]	91	100 [96.0–100]	87	100 [95.8–100]
	Day 42	85	100 [95.8–100]	90	100 [96.0–100]	83	100 [95.7–100]
	Month 12	88	100 [95.9–100]	92	98.9 [94.1–100]	87	100 [95.8–100]
SCR [95% CI]	Day 21	87	98.9 [93.8–100]	91	100 [96.0–100]	87	97.7 [91.9–99.7]
	Day 42	85	100 [95.8–100]	90	100 [96.0–100]	83	96.4 [89.8–99.2]
	Month 12	88	97.7 [92.0–99.7]	92	97.8 [92.4–99.7]	87	94.3 [87.1–98.1]
GMFR [95% CI]	Day 21	87	41.0 [35.1–47.9]	91	39.5 [34.1–45.7]	87	61.8 [48.4–78.8]
	Day 42	85	305.1 [251.2–370.5]	90	212.0 [182.5–246.2]	83	119.8 [92.3–155.4]
	Month 12	88	37.5 [31.0–45.2]	92	20.1 [17.4–23.1]	87	28.3 [22.2–36.1]
Neutralising antibody
VRR (95% CI)	Day 21	54	53.7 [39.6–67.4]	60	86.7 [75.4–94.1]	28	85.7 [67.3–96.0]
	Day 42	54	98.1 [90.1–100]	57	100 [93.7–100]	28	100 [87.7–100]
	Month 12	50	92.0 [80.8–97.8]	55	98.2 [90.3–100]	28	89.3 [71.8–97.7]

Footnote: 3–9 years age group = children from Study B who received the first vaccine dose at 3–9 years of age.

10–17 years age group = children from Study B who received the first vaccine dose at 10–17 years of age.

N = number of children with available results.

95% CI = 95% confidence interval.

SPR = seroprotection rate.

SCR = seroconversion rate.

GMFR = geometric mean fold rise.

VRR = vaccine response rate.