Long-term booster schedules with AS03A-adjuvanted heterologous H5N1 vaccines induces rapid and broad immune responses in Asian adults

Table 2 Hemagglutination inhibition-based immunogenicity in the per-protocol immunogenicity cohort

Vaccine	Sample time-point	SCR/booster SCR^†		SPR
Vaccine	Sample time-point	n/N; % (95% CI)		n/N; % (95% CI)
		Primary strain	Booster strain	Primary strain	Booster strain
AS03 _A -H5N1	Day 0	–	–	15/933; 1.6	1/933; 0.1
				(0.9, 2.6)	(0.0, 0.6)
	Day 21	393/925; 42.5	24/925; 2.6	412/925; 44.5	27/925; 2.9
		(39.3, 45.7)	(1.7, 3.8)	(41.3, 47.8)	(1.9, 4.2)
	Day 42	866/924; 93.7	464/924; 50.2	871/924; 94.3	464/924; 50.2
		(92.0, 95.2)	(46.9, 53.5)	(92.6, 95.7)	(46.9, 53.5)
Heterologous booster	Month 6	–	–	103/251; 41.0	9/251; 3.6
				(34.9, 47.4)	(1.7, 6.7)
	Month 6 + 21	233/256; 91.0^†	241/256; 94.1^†	242/251; 96.4	238/251; 94.8
		(86.8, 94.2)	(90.5, 96.7)	(93.3, 98.3)	(91.3, 97.2)
Non-adjuvanted-H5N1	Day 0	–	–	5/236; 2.1	0/236; 0.0
				(0.7, 4.9)	(0.0, 1.6)
	Day 21	8/234; 3.4	0/234; 0.0	16/234; 6.8	0/234; 0.0
		(1.5, 6.6)	(0.0, 1.6)	(4.0, 10.9)	(0.0, 1.6)
	Day 42	13/234; 5.6	1/234; 0.4	24/234; 10.3	1/234; 0.4
		(3.0, 9.3)	(0.0, 2.4)	(6.7, 14.9)	(0.0, 2.4)
Heterologous booster	Month 6	–	–	4/224; 1.8	0/224; 0.0
				(0.5, 4.5)	(0.0, 1.6)
	Month 6 + 21	112/228; 49.1^†	106/228; 46.5^†	120/223; 53.8	105/223; 47.1
		(42.5, 55.8)	(39.9, 53.2)	(47.0, 60.5)	(40.4, 53.9)
	Month 6 + 42	173/228; 75.9^†	189/228; 82.9^†	180/228; 78.9	189/228; 82.9
		(69.8, 81.3)	(77.4, 87.5)	(73.1, 84.1)	(77.4, 87.5)

CI, Confidence Interval; n/N, number of subjects fulfilling criteria for defined outcome/total number of subjects in group; SCR, seroconversion rates defined as percentage of subjects achieving an increase in HI titers from <1:10 to ≥1:40 or at least a 4-fold post-vaccination increase in HI titer from a pre-vaccination titer ≥1:10; ^†Booster SCR was SCR based on increases in HI antibody titers from pre-vaccination titers at Month 6; SPR, seroprotection rate defined as the percentage of subjects with HI titers ≥1:40 following vaccination; primary vaccine strain, H5N1/A/Vietnam/1194/2004; booster strain H5N1/A/Indonesia/5/2005.

ISSN: 1471-2334