Table 3.

Non-inferiority of QIV versus TIVs against shared strains according to HI-assay based GMT and SCR at Day 21 in the per-protocol immunogenicity sub-cohort

Vaccine antigen	Adjusted GMT		Adjusted GMT ratio (95% CI)†
	TIV-Vic + TIV-Yam, N = 1135	QIV, N = 1801	TIV-Vic + TIV-Yam/QIV
A/California/7/2009 (H1N1)	214.8	201.6	1.07 (0.96, 1.18)
A/Victoria/210/2009 (H3N2)	312.2	318.5	0.98 (0.90, 1.07)
B/Brisbane/60/2008	TIV-Vic, N = 605	QIV, N = 1801	TIV-Vic/QIV
(Victoria lineage)	395.3	404.2	0.98 (0.9, 1.07)
B/Brisbane/3/2007	TIV-Yam, N = 530	QIV, N = 1801	TIV-Yam/QIV
(Yamagata lineage)	584.7	600.8	0.97 (0.89, 1.07)
	Number seroconverted (SCR)		SCR difference (95% CI)‡
	TIV-Vic + TIV-Yam, N = 1135	QIV, N = 1801	TIV-Vic + TIV-Yam minus QIV
A/California/7/2009 (H1N1)	892 (78.6%)	1396 (77.5%)	1.08 (−2.03, 4.11)
A/Victoria/210/2009 (H3N2)	769 (67.8%)	1287 (71.5%)	−3.71 (−7.15, −0.30)
B/Brisbane/60/2008	TIV-Vic, N = 605	QIV, N = 1801	TIV-Vic minus QIV
(Victoria lineage)	335 (55.4%)	1046 (58.1%)	−2.71 (−7.29, 1.83)
B/Brisbane/3/2007	TIV-Yam, N = 530	QIV, N = 1801	TIV-Yam minus QIV
(Yamagata lineage)	313 (59.1%)	1112 (61.7%)	−2.69 (−7.47, 2.01)

^†Non-inferiority was demonstrated if the lower limit of the 95% CI was ≤1.5; ^‡Non-inferiority was demonstrated if the lower limit of the 95% CI ≤10.0.

CI confidence interval, GMT geometric mean titer, HI Hemagglutination inhibition, SCR seroconversion rate (proportion with pre-vaccination titer <1:10 and a post-vaccination titer ≥1:40, or a pre-vaccination titer ≥1:10 and at least a four-fold increase in post-vaccination titer), TIV trivalent inactivated influenza vaccine, Vic Victoria lineage B strain, Yam Yamagata lineage B strain, QIV quadrivalent inactivated influenza vaccine.