Table 1.
Immune Response Against Shigella sonnei as Measured by ELISA and SBA (Per-Protocol Set)
| Day 1, Baseline | Day 15 | Day 29 | Day 85a/Day 169,b Before Injection 2 | Day 113a/Day 197b | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Parameter | Study Group | n | Value | n | Value or % | n | Value or % | n | Value or % | n | Value or % |
| ELISA | |||||||||||
| GMC, EU/mL | altSonflex3M + altSonflex6M | 68 | 11.7 (9.4–14.6) | 68 | 229.1 (152.5–344.0) | 67 | 235.5 (156.8–353.7) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 29 | 287.6 (144.1–574.1) | 26 | 387.8 (206.6–727.8) | |
| altSonflex6M | … | … | … | … | … | … | 33 | 94.8 (55.2–162.9) | 33 | 167.2 (104.3–267.9) | |
| Placebo | 34 | 21.0 (13.2–33.6) | 32 | 18.4 (11.6–29.3) | 32 | 18.1 (11.5–28.6) | 28 | 19.0 (11.1–32.3) | 28 | 19.9 (11.8–33.7) | |
| 4-fold increase,c % | altSonflex3M + altSonflex6M | … | … | 68 | 76.5 (64.6–85.9) | 67 | 77.6 (65.8–86.9) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 29 | 75.9 (56.5–89.7) | 26 | 84.6 (65.1–95.6) | |
| altSonflex6M | … | … | … | … | … | … | 33 | 63.6 (45.1–79.6) | 33 | 78.8 (61.1–91.0) | |
| Placebo | 34 | … | 32 | 0.0 (.0–10.9) | 32 | 0.0 (.0–10.9) | 28 | 0.0 (.0–12.3) | 28 | 0.0 (.0–12.3) | |
| GMRc | altSonflex3M + altSonflex6M | … | … | 68 | 19.6 (13.4–28.6) | 67 | 20.0 (13.6–29.4) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 29 | 18.1 (9.0–36.5) | 26 | 22.8 (11.9–43.6) | |
| altSonflex6M | … | … | … | … | … | … | 33 | 11.4 (6.6–19.9) | 33 | 20.1 (12.2–33.3) | |
| Placebo | 34 | … | 32 | 0.9 (.8–1.1) | 32 | 0.9 (.7–1.1) | 28 | 1.0 (.8–1.2) | 28 | 1.0 (.8–1.3) | |
| SBA | |||||||||||
| GMT, IC50 | altSonflex3M + altSonflex6M | 18 | 21.5 (14.5–31.7) | 18 | 1442.2 (485.6–4283.4) | 18 | 911.2 (345.2–2405.0) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 8 | 1151.4 (412.1–3216.7) | 7 | 764.7 (259.7–2252.1) | |
| altSonflex6M | … | … | … | … | … | … | 9 | 878.4 (527.7–1462.1) | 9 | 589.6 (194.3–1789.3) | |
| Placebo | 10 | 21.4 (11.9–38.5) | 10 | 22.1 (11.4–42.8) | 10 | 22.9 (12.9–40.5) | 10 | 22.1 (11.4–42.9) | 10 | 23.8 (12.4–45.7) | |
| 4-fold increase,c% | altSonflex3M + altSonflex6M | … | … | 18 | 83.3 (58.6–96.4) | 18 | 83.3 (58.6–96.4) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 8 | 100 (63.1–100) | 7 | 71.4 (29.0–96.3) | |
| altSonflex6M | … | … | … | … | … | … | 9 | 100 (66.4–100) | 9 | 88.9 (51.8–99.7) | |
| Placebo | … | … | 10 | 0.0 (.0–30.8) | 10 | 0.0 (.0–30.8) | 10 | 0.0 (.0–30.8) | 10 | 0.0 (.0–30.8) | |
| GMRc | altSonflex3M + altSonflex6M | … | … | 18 | 67.1 (23.5–192.1) | 18 | 42.4 (17.3–104.0) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 8 | 38.5 (13.5–109.7) | 7 | 23.5 (7.2–76.4) | |
| altSonflex6M | … | … | … | … | … | … | 9 | 53.2 (32.0–88.6) | 9 | 35.7 (11.8–108.4) | |
| Placebo | … | … | 10 | 1.0 (1.0–1.1) | 10 | 1.1 (.9–1.3) | 10 | 1.0 (1.0–1.1) | 10 | 1.1 (.9–1.3) | |
Data are value or percentage (95% confidence interval).
Abbreviations: ELISA, enzyme-linked immunosorbent assay; EU, ELISA unit; GMC, geometric mean concentration; GMR, geometric mean ratio; GMT, geometric mean titer; IC50, half-maximal (50%) inhibitory concentration; n, number of participants in the group; SBA, serum bactericidal assay.
aAssessment time point for altSonflex3M group.
bAssessment time point for altSonflex6M group.
cComparison versus baseline. altSonflex3M + altSonflex6M, pooled data for altSonflex3M and altSonflex6M groups; altSonflex3M, participants randomized to receive altSonflex1-2-3 vaccine at 3-month interval; altSonflex6M, participants randomized to receive altSonflex1-2-3 vaccine at 6-month interval; placebo, participants randomized to receive placebo.