Table 3.
Vibriocidal antibody titers and proportion of ≥ 4-fold rise from baseline GMT to V. cholerae (include O1 Inaba, O1 Ogawa, and O139) in adults and children
| Adults (aged 18 years and above) | O1 Inaba | O1 Ogawa | O139 | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vaccine group (N = 54) | Placebo group (N = 54) | P value | Vaccine group (N = 37) | Placebo group (N = 46) | P value | Vaccine group (N = 46) | Placebo group (N = 50) | P value | ||
| Baseline | GMT | 16.1 | 16.1 | 1 | 23.7 | 43.1 | 0.26 | 4.8 | 4.1 | 0.71 |
| 14 days after first vaccine dose | GMT | 188.1 | 17.1 | < 0.001 | 318.1 | 59.2 | < 0.001 | 14.6 | 4.3 | 0.01 |
| GMF* rise | 11.2 | 1.1 | < 0.001 | 13.4 | 1.4 | < 0.001 | 3.1 | 1.1 | < 0.001 | |
| No. seroconverted† (%) | 37 (70) | 2 (4) | < 0.001 | 24 (65) | 5 (11) | < 0.001 | 13 (28) | 2 (4) | 0.001 | |
| 14 days after second vaccine dose | GMT | 254.1 | 18.8 | < 0.001 | 306.4 | 61 | < 0.001 | 15.1 | 4.2 | < 0.001 |
| GMF* rise | 15.1 | 1.2 | < 0.001 | 12.9 | 1.4 | < 0.001 | 3.2 | 1 | < 0.001 | |
| No. seroconverted† (%) | 43 (81) | 4 (7) | < 0.001 | 26 (70) | 6 (13) | < 0.001 | 14 (30) | 2 (4) | 0.001 | |
| Children (aged 1–17 years) | O1 Inaba | O1 Ogawa | O139 | |||||||
| Vaccine group (N = 53) | Placebo group (N = 54) | P value | Vaccine group (N = 45) | Placebo group (N = 54) | P value | Vaccine group (N = 49) | Placebo group (N = 53) | P value | ||
| Baseline | GMT | 6.2 | 8.5 | 0.48 | 4.2 | 7.2 | 0.17 | 1.6 | 1.6 | 0.92 |
| 14 days after first vaccine dose | GMT | 136.8 | 10.8 | < 0.001 | 143.6 | 7.5 | < 0.001 | 17.1 | 1.6 | < 0.001 |
| GMF* rise | 21.9 | 1.3 | < 0.001 | 34.6 | 1.1 | < 0.001 | 10.7 | 1.0 | < 0.001 | |
| No. seroconverted† (%) | 39 (74) | 4 (7) | < 0.001 | 36 (80) | 4 (7) | < 0.001 | 26 (53) | 1 (2) | < 0.001 | |
| 14 days after second vaccine dose | GMT | 106.7 | 12.4 | < 0.001 | 143.6 | 7 | < 0.001 | 9.6 | 1.8 | < 0.001 |
| GMF* rise | 17.1 | 1.5 | < 0.001 | 34.6 | 1 | < 0.001 | 6 | 1.1 | < 0.001 | |
| No. seroconverted† (%) | 41 (77) | 6 (11) | < 0.001 | 38 (84) | 3 (5) | < 0.001 | 21 (43) | 3 (6) | < 0.001 | |
GMT = geometric mean titers.
Geometric mean fold rise (GMFr) from baseline to 14 days after first dose or from baseline to 14 days after second dose. Adjusted GMFr values after first or second dose to correct for difference in male:female enrolled adult vaccine and placebo recipients all remained statistically significant when compared with placebo (P < 0.001): O1 Inaba (11.8 and 14.5, respectively), O1 Ogawa (8.2 and 7.6, respectively), and O139 (2.9 and 3.2, respectively).
Number with ≥ 4-fold rise in titers from baseline to 14 days after first dose or from baseline to 14 days after second dose. Primary endpoint (O1 Inaba after second dose), proportion difference between vaccine and placebo group (lower boundary of one-tailed 97.5% confidence intervals [CI]) was 74% (56%) and 66% (48%) among adults and children, respectively. Vaccine group is superior to the placebo group as the lower limit of the proportion difference is greater than clinical margin (30%).