Antibody responses against heterologous H5N1 strains for an MF59-adjuvanted cell culture–derived H5N1 (aH5n1c) influenza vaccine in adults and older adults

Figures & data

Table 1. Study population demographics.

	Age 18–64 y (n = 488)	Age ≥65 y (n = 700)
Age, mean ± SD (y)	39.0 ± 13.7	71.2 ± 5.1
Male, n (%)	203 (42)	293 (42)
Weight, mean ± SD (kg)	74.1 ± 15.1	71.0 ± 15.9
Height, mean ± SD (cm)	167.8 ± 10.5	164.1 ± 10.7
BMI, mean ± SD (kg/m^2)	26.2 ± 4.3	26.1 ± 4.0
Previous influenza vaccination, n (%)	118 (24)	429 (61)
Influenza vaccination within 12 months prior to study, n (%)	98 (20)	388 (55)
Race, n (%)
White	291 (60)	445 (64)
Black	97 (20)	10 (1)
Asian	93 (19)	240 (34)
Native American	2 (<1)	2 (<1)
Other	5 (1)	3 (<1)
Hispanic ethnicity, n (%)	107 (22)	17 (2)

Table 2. HI and MN antibody responses (GMT and GMR) against H5N1 at Day 1 and Day 43 by age group.

	HI			MN
	GMT Day 1 (95% Cl)	GMT Day 43 (95% Cl)	GMR Day 43/Day 1 (95% Cl)	GMT Day 1 (95% Cl)	GMT Day 43 (95% Cl)	GMR Day 43/Day 1 (95% Cl)
Age 18–64 y
Homologous	n = 478	n = 451	n = 451	n = 69
Turkey/2005	6.11 (5.78–6.46)^a	250 (208–302)^a	41 (34–49)^a	6.7 (5.62–7.98)	410 (313–537)	61 (44–86)
Heterologous	n = 69			n = 69
Anhui/2005	5.02 (4.87–5.18)	11 (6.64–17)	2.09 (1.29–3.37)	16 (12–21)	156 (131–186)	9.93 (7.47–13)
Egypt/2010	5.87 (4.51–7.63)	39 (22–71)	6.52 (3.62–12)	15 (11–22)	522 (398–685)	34 (23–49)
Hubei/2010	7.12 (5.01–10)	56 (31–102)	7.3 (4.01–13)	7.2 (6–8.63)	51 (41–63)	7.07 (5.56–8.98)
Indonesia/2005	5.02 (4.87–5.18)	16 (9.17–28)	3.12 (1.81–5.39)	8.79 (7–11)	114 (89–146)	13 (9.42–18)
Vietnam/1203/2004	5.97 (4.41–8.06)	44 (24–81)	6.99 (3.84–13)	5.59 (4.98–6.27)	27 (21–34)	4.76 (3.74–6.06)
Age ≥65 y
Homologous	n = 693	n = 673	n = 673	n = 35
Turkey/2005	8.29 (7.57–9.08)^a	129 (110–152)^a	16 (13–19)^a	7.49 (5.87–9.56)	169 (107–268)	23 (13–39)
Heterologous	n = 35			n = 35
Anhui/2005	5 (5–5)	8.53 (5.92–12)	1.71 (1.18–2.46)	28 (20–41)	128 (99–165)	4.52 (2.93–6.97)
Egypt/2010	6.86 (4.94–9.53)	27 (15–47)	3.88 (2.27–6.64)	25 (15–41)	303 (206–447)	12 (6.69–22)
Hubei/2010	7.43 (5.28–10)	36 (20–64)	4.83 (2.8–8.32)	11 (7.98–16)	42 (31–58)	3.75 (2.6–5.4)
Indonesia/2005	5 (5–5)	12 (8.02–18)	2.39 (1.6–3.56)	18 (13–27)	87 (63–120)	4.77 (3.1–7.34)
Vietnam/1203/2004	7.81 (5.24–12)	34 (19–63)	4.41 (2.57–7.57)	7.32 (5.39–9.95)	27 (19–39)	3.68 (2.62–5.17)

Abbreviations: CI, confidence interval; GMR, geometric mean ratio; GMT, geometric mean titer; HI, hemagglutination inhibition; MN, microneutralization.

^a97.5% CI.

Figure 1. Percentage of subjects with hemagglutination inhibition (HI) titers ≥1:40 in adults aged 18–64 y (a) and aged ≥65 y (b). Error bars represent the 95% confidence interval (CI) for heterologous strains and the 97.5% CI for the homologous strain.

Figure 2. Percentage of subjects with microneutralization (MN) titers ≥1:40 in adults aged 18–64 y (a) and aged ≥65 y (b). Error bars represent the 95% confidence interval (CI) for heterologous strains and the 97.5% CI for the homologous strain.

Figure 3. Percentage of subjects with seroconversion (defined as hemagglutination inhibition [HI] ≥1:40 for subjects negative at baseline [HI <1:10] or a minimum 4-fold increase in HI titer for subjects positive at baseline [HI ≥ 1:10]) on Day 43) or a ≥4-fold increase in microneutralization (MN) titers. (a, b) Seroconversion in adults aged 18–64 y (a) and ≥65 y (b). Error bars represent the 97.5% confidence interval (CI). (c, d) at least 4-fold increase in MN titers in adults aged 18–64 y (c) and ≥65 y (d). Error bars represent the 95% CI.