Table 3.
Clinical and Bacteriologic Responses to Challenge
| Vaccine Efficacy (95% CI) orP Value |
||||||
|---|---|---|---|---|---|---|
| Clinical or Bacteriological Endpoint | All Vaccinees | Vaccine Day 10 | Vaccine 3 mo | All Placebos | Day 10 | 3 mo |
| Total challenged | 68 | 35 | 33 | 66 | ||
| No. with severe cholera (%) | 3 (4.4) | 1 (2.9) | 2 (6.1) | 28 (42.4) | 93.3% (56.2%–100%) | 85.7% (46.2%–100%) |
| No. with moderate or severe cholera (%)a | 6 (8.8) | 2 (5.7) | 4 (12.1) | 39 (59.1) | 90.3% (61.7%–100%) | 79.5% (49.1%–100%) |
| No. with mild cholerab or worse (%) | 20 (29.4) | 5 (14.3) | 15 (45.5) | 61 (92.4) | 84.5% (67.0%–100%) | 50.8% (33.6%–66.8%) |
| Median diarrheal stool volume, mL (IQR) | 0 (0–311) | 0 (0–0) | 178 (0–988) | 4377 (1563–8087) | <.0001 | <.0001 |
| Median number of diarrheal stools (IQR) | 0 (0–3.8) | 0 (0–0) | 2.0 (0–5.5) | 22.5 (9.8–39.3) | <.0001 | <.0001 |
| Median peak Vibrio cholerae O1 count, CFU/mL (IQR) | 4.2 × 101 (0–3.5 × 105) | 0 (0–2.7 × 103) | 9.7 × 104 (0–1.7 × 107) | 3.2 × 107 (6.1 × 106–1.2 × 108) | <.0001 | <.0001 |
| No. with fever (%)c | 3 (4.4) | 1 (2.9) | 2 (6.1) | 18 (27.3) | .0025 | .0159 |
| No. with nausea/vomiting (%) | 16 (23.5) | 9 (25.7) | 7 (21.2) | 38 (57.6) | .0032 | .0006 |
| No. with abdominal cramping (%) | 18 (26.5) | 8 (22.9) | 10 (30.3) | 45 (68.2) | <.0001 | .0005 |
| No. with malaise (%) | 16 (23.5) | 8 (22.9) | 8 (24.2) | 41 (62.1) | .0003 | .0006 |
Abbreviations: CFU, colony-forming units; CI, confidence interval; IQR, interquartile range.
a Moderate and severe cholera (study primary endpoint) is defined as ≥3 L and ≥5 L of cumulative diarrheal stool, respectively.
b Mild diarrhea is defined as the passage of ≥2 unformed stools (grade 3–5) over a 48-hour period that equals or exceeds 200 mL or a single unformed stool of ≥300 mL and <3 L total diarrhea.
c Fever is defined as ≥38.0°C (100.4°F).