Table 2 Antibody responses to the A(H5N8) vaccine antigen and cross-reactivity of vaccine-induced antibodies with heterologous A(H5N1) clade 2.3.4.4b viruses measured using MN and HI assays and FMIA
Previously unvaccinated (n = 30) | Previously vaccinated (n = 9) | ||||||
|---|---|---|---|---|---|---|---|
Pre-vaccination | 3 weeks post 1st dose | 3 weeks post 2nd dose | Pre-vaccination | 3 weeks post 1st dose | 3 weeks post 2nd dose | ||
MN (A/Astrakhan/ 3212/2020) | GMT [95% CI] | 5.0 [5.0–5.0] | 15 [9.6–22] | 47 [29–78] | 5.8 [4.6–7.4] | 252 [66–962] | 140 [47–412] |
% positive ≥1:10 (n/n) | 0% (0/30) | 63% (19/30) | 93% (28/30) | 22% (2/9) | 100% (9/9) | 100% (9/9) | |
% seropositive ≥1:20 (n/n) | 0% (0/30) | 47% (14/30) | 83% (25/30) | 0% (0/9) | 100% (9/9) | 100% (9/9) | |
HI (A/Astrakhan/ 3212/2020) | GMT [95% CI] | 6.1 [5.2–7.2] | 42 [30–59] | 97 [70–133] | 17 [8.7–35] | 273 [104–718] | 246 [108–560] |
% positive ≥1:10 (n/n) | 20% (6/30) | 93% (28/30) | 100% (30/30) | 78% (7/9) | 100% (9/9) | 100% (9/9) | |
% seropositive ≥1:40 (n/n) | 0% (0/30) | 73% (22/30) | 97% (29/30) | 11% (1/9) | 100% (9/9) | 100% (9/9) | |
MN (A/blue fox/ UH/004/2023) | GMT [95% CI] | 10 [7.7–13] | 34 [24–48] | 70 [47–104] | 12 [6.5–21] | 229 [78–676] | 195 [80-480] |
% positive ≥1:10 (n/n) | 63% (19/30) | 97% (29/30) | 100% (30/30) | 67% (6/9) | 100% (9/9) | 100% (9/9) | |
% seropositive ≥1:20 (n/n) | 27% (8/30) | 80% (24/30) | 93% (28/30) | 44% (4/9) | 100% (9/9) | 100% (9/9) | |
HI (A/Texas/ 37/2024) | GMT [95% CI] | 7.6 [6.0–9.7] | 54 [37–79] | 113 [82–156] | 29 [11–72] | 408 [162–1029] | 401 [175-916] |
% positive ≥1:10 (n/n) | 37% (11/30) | 93% (28/30) | 100% (30/30) | 78% (7/9) | 100% (9/9) | 100% (9/9) | |
% seropositive ≥1:40 (n/n) | 7% (2/30) | 70% (21/30) | 97% (29/30) | 44% (4/9) | 100% (9/9) | 100% (9/9) | |
FMIA (A/Michigan/ 90/2024 HA) | GMC [95% CI] | 18 [14–24] | 56 [41–77] | 174 [118–257] | 76 [30–195] | 1520 [613–3790] | 1270 [592–2720] |
