Table 5.
Safety, immunogenicity, and protectivity of live H5 viruses in chickens
| Virus | Dose EID50 | Post‐vaccination | Post‐challenge survival | ||
|---|---|---|---|---|---|
| Weight* | Survival** | Ab.*** | |||
| Ch/Ku | 104 | – | 0/4 | – | – |
| Ku‐at | 106 | 82 ± 7 | 0/4 | – | – |
| VN‐Len | 107 | 135 ± 13 | 9/9 | 2·4 ± 0·5 | 2/8 |
| VN‐Gull | 106 | 133 ± 13 | 9/9 | 3·3 ± 0·7 | 7/8 |
| Ku‐Len | 107 | 137 ± 12 | 9/9 | 2·3 ± 0·5 | 2/8 |
| Ku‐Gull | 106 | 130 ± 19 | 9/9 | 3·2 ± 0·7 | 8/8 |
| Placebo | – | 140 ± 10 | 4/4 | – | 0/4 |
The 10‐day‐old chickens were once infected intranasal with indicated dose of viruses and on day 24, were challenged by H5N1 A/Chicken/Kurgan/3/05 virus (∼100 LD50).
*Weight: average chicken weight, percentage of start value, determined on day 6 post‐vaccination.
**Survival: Survival: number survived/number infected.
***Ab: antibody to H5N1, log of geometrical mean of the ELISA titer.