Table 1.
Serum Antibody Titers by Vaccine Group as Measured With HI and VN Assays
| Vaccine Group | Dose, µg | Serum Antibody Titer by HI Assay |
Serum Antibody Titer by VN Assay |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Titer for 1st Dose, GMT (95% CI) | Ferrets With Titer ≥40, No.a | Titer for 2nd Dose, GMT (95% CI) | Ferrets With Titer ≥40, No.a | 1st Dose, GMT (95% CI) | Ferrets With Titer ≥40, No.a | 2nd Dose, GMT (95% CI) | Ferrets With Titer ≥40, No.a | ||
| Saline | 0 | <20 | 0 | <20 | 0 | <20 | 0 | <20 | 0 |
| Unadjuvanted | 3.75 | <20 | 0 | <20 | 0 | 12.6 (4.3–37.7) | 2 | 11.2 (4.3–29.5) | 1 |
| 15 | <20 | 0 | <20 | 0 | 8.9 (3.4–23.4) | 1 | 6.3 (3.5–11.4) | 0 | |
| 45 | <20 | 0 | <20 | 0 | 10 (4.5–22.2) | 0 | 8.9 (3.4–23.4) | 1 | |
| MF59 | 3.75 | 11.2 (4–29.5) | 1 | 44.9 (10.9–184.3) | 5 | 63.5 (35.1–115.0) | 6 | 201.6 (83.5–486.5)b | 6 |
| 15 | 40.0 (11.8–135.1) | 5 | 320.0 (19.4–5256)b | 5 | 100.8 (47.5–213.7) | 6 | 905 (200.2–4092)b | 6 | |
| AS03 | 3.75 | 71.2 (34.9–145.7) | 6 | 905.1 (100.8–8125)b,d | 6 | 179.6 (103.9–310.6) | 6 | 1280 (414.7–3951)b,d | 6 |
| 15 | 127.0 (59.9–269) | 6 | 1016 (243.0–4248)b,c | 6 | 201.6 (138.5–293.5) | 6 | 1810 (984.9–3327)b,c | 6 | |
Abbreviations: CI, confidence interval; GMT, geometric mean titer; HI, hemagglutination inhibition; VN, virus neutralization.
a There were 6 ferrets per group. Titers <20 were arbitrarily set at 5. Statistical significance was determined by analysis of variance using log-transformed antibody titer, with Bonferroni adjustment for multiple comparisons.
b P < .001 for comparisons with saline control and unadjuvanted vaccine groups.
c P < .01 for comparison with MF59-adjuvanted, 3.75-µg vaccine group.
d P < .05 for comparison with MF59-adjuvanted, 3.75-µg vaccine group.