Table 1.
Pre‐challenge serology
| Vaccine regimen* | Weeks after first immunization | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3 | 6 | 8 | 10 | 12 | 16 | 20 | 51 | |||||||||
| VN1203 | 52·5 | 52·5 | 260 | 260 | 580 | 580 | 100 | 100 | 150 | 150 | 135 | 135 | 180 | 180 | 180 | 180 |
| VN1203 HA D94N | 12·5 | 22·5 | 35 | 40 | 140 | 230 | 52·5 | 60 | 35 | 70 | 12·5 | 30 | 27·5 | 32·5 | 20 | 20 |
| VN1203 HA S124D | 12·5 | 25 | 30 | 80 | 90 | 560 | 60 | 240 | 40 | 90 | 10 | 50 | 17·5 | 45 | 10 | 15 |
| VN1203 HA K189R | 12·5 | 25 | 100 | 130 | 160 | 140 | 80 | 60 | 40 | 70 | 20 | 25 | 27·5 | 27·5 | 25 | 22·5 |
| VN1203 HA D94N:S124D | 17·5 | 30 | 90 | 110 | 280 | 480 | 130 | 90 | 55 | 90 | 10 | 17·5 | 35 | 65 | 30 | 60 |
| VN1203 HA D94N:K189R | 17·5 | 35 | 120 | 30 | 300 | 110 | 110 | 60 | 85 | 45 | 35 | 10 | 55 | 30 | 20 | 5 |
| VN1203 HA S124D:K189R | 20 | 25 | 90 | 72·5 | 360 | 320 | 200 | 55 | 160 | 60 | 70 | 32·5 | 60 | 27·5 | 50 | 20 |
| VN1203 HA D94N:S124D:K189R | 17·5 | 20 | 90 | 35 | 160 | 120 | 150 | 20 | 120 | 55 | 35 | 17·5 | 75 | 45 | 20 | 7·5 |
| DKHUN795 | 22·5 | 20 | 70 | 22·5 | 340 | 55 | 110 | 10 | 130 | 27·5 | 62·5 | 17·5 | 35 | 15 | 25 | 5 |
| A | 12·5 | 22·5 | 45 | 7·5 | 640 | 27·5 | 120 | 10 | 140 | 22·5 | 45 | 0 | 65 | 7·5 | 60 | 0 |
| D | 15 | 17·5 | 85 | 7·5 | 680 | 42·5 | 160 | 16·7 | 240 | 20 | 120 | 12·5 | 120 | 7·5 | 180 | 5 |
| PBS | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Mean microneutralization titers (n = 4 ferrets except at week 51 n = 2 ferrets) against the homologous strain in plain font and against VN1203 (the challenge virus) in bold, italic font.
HA, hemagglutinin.
*Ferrets were immunized on weeks 0, 3, and 6 (after the bleed weeks 3 and 6).