Table 1.
Immunogenicity response criteria for pandemic influenza vaccine licensure.
| Parameter | US (FDA) acceptance criteria |
European (CHMP) acceptance criteria |
|---|---|---|
| Geometric mean HI titer | No standard | No standard |
| Mean geometric increase (ratio day 42 GMT/day 0 GMT) | No standard | >2.5% |
| Seroconversion (HI) rate or significant increase in titer | Lower limit of 95% CI >40% | >40% |
| Microneutralization assay titer | No standard | No standard |
| Seroprotection rate (HI titer ≥40) | Lower limit of 95% CI >70% | >70% |
CHMP: Committee for Medicinal Products for Human Use; GMT: Geometric mean titer; HI: Hemagglutination inhibition.