Table 3.
Immune Response Against Shigella flexneri 1b as Measured by ELISA and SBA (Per-Protocol Set)
| Parameter | Study Group | Day 1, Baseline | Day 15 | Day 29 | Day 85a/Day 169,b Before Injection 2 | Day 113a/Day 197b | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| n | Value | n | Value or % | n | Value or % | n | Value or % | n | Value or % | ||
| ELISA | |||||||||||
| GMC, EU/mL | altSonflex3M + altSonflex6M | 68 | 23.2 (16.2–33.2) | 68 | 112.1 (79.1–159.0) | 67 | 103.1 (73.1–145.4) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 29 | 79.1 (45.3–138.1) | 26 | 129.7 (79.6–211.5) | |
| altSonflex6M | … | … | … | … | … | … | 33 | 48.5 (30.1–78.0) | 33 | 73.0 (48.6–109.7) | |
| Placebo | 34 | 26.9 (15.3–47.3) | 32 | 27.4 (16.1–46.7) | 32 | 27.0 (15.8–46.3) | 28 | 27.2 (15.5–47.7) | 28 | 26.1 (14.6–46.9) | |
| 4-fold increasec, % | altSonflex3M + altSonflex6M | … | … | 68 | 48.5 (36.2–61.0) | 67 | 43.3 (31.2–56.0) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 29 | 24.1 (10.3–43.5) | 26 | 42.3 (23.4–63.1) | |
| altSonflex6M | … | … | … | … | … | … | 33 | 15.2 (5.1–31.9) | 33 | 30.3 (15.6–48.7) | |
| Placebo | … | … | 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 | 4.8 (3.6–6.6) | 67 | 4.3 (3.3–5.7) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 29 | 3.1 (2.1–4.4) | 26 | 4.7 (2.9–7.8) | |
| altSonflex6M | … | … | … | … | … | … | 33 | 2.2 (1.7–2.9) | 33 | 3.4 (2.5–4.5) | |
| Placebo | … | … | 32 | 1.0 (.8–1.2) | 32 | 1.0 (.8–1.2) | 28 | 1.0 (.8–1.1) | 28 | 0.9 (.8–1.1) | |
| SBA | |||||||||||
| GMT, IC50 | altSonflex3M + altSonflex6M | 18 | 8417.6 (3871.6–18302) | 18 | 46293 (30160–71057) | 18 | 56972 (43473–74662) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 8 | 58211 (29828–114E3) | 7 | 85066 (42119–172E3) | |
| altSonflex6M | … | … | … | … | … | … | 9 | 30114 (20412–44427) | 9 | 103E3 (49522–213E3) | |
| Placebo | 10 | 6573.9 (1649.9–26194) | 10 | 8181.0 (2337.8–28629) | 10 | 8071.2 (2480.5–26262) | 10 | 18084 (8945.6–36558) | 10 | 25229 (12693–50148) | |
| 4-fold increasec, % | altSonflex3M + altSonflex6M | … | … | 18 | 55.6 (30.8–78.5) | 18 | 55.6 (30.8–78.5) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 8 | 37.5 (8.5–75.5) | 7 | 57.1 (18.4–90.1) | |
| altSonflex6M | … | … | … | … | … | … | 9 | 22.2 (2.8–60.0) | 9 | 66.7 (29.9–92.5) | |
| Placebo | … | … | 10 | 10.0 (.3–44.5) | 10 | 0.0 (.0–30.8) | 10 | 30.0 (6.7–65.2) | 10 | 40.0 (12.2–73.8) | |
| GMRc | altSonflex3M + altSonflex6M | … | … | 18 | 5.5 (2.3–13.2) | 18 | 6.8 (3.1–14.7) | … | … | … | … |
| altSonflex3M | … | … | … | … | … | … | 8 | 6.1 (1.7–22.2) | 7 | 9.2 (1.3–63.3) | |
| altSonflex6M | … | … | … | … | … | … | 9 | 3.2 (1.1–8.9) | 9 | 10.8 (2.9–40.6) | |
| Placebo | … | … | 10 | 1.2 (.7–2.3) | 10 | 1.2 (.8–2.0) | 10 | 2.8 (1.1–6.8) | 10 | 3.8 (1.4–10.7) | |
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.