Table 1. Baseline characteristics of study populations on the day of typhoid challenge.
| Parameter | Study A (placebo arm of vaccine/challenge study) | Study B (challenge study) |
|---|---|---|
| Number of participants | 30 | 20 |
| Age, median years (IQR) b | 24.6 (21.7–39.4) | 26.5 (23.4–38.4) |
| Male gender, n (%) b | 18 (60) | 12 (60) |
| Weight, median kg (IQR) b | 75.9 (68.9–82) (n = 18) | 79.4 (71.7–87.0) (n = 15) |
| Height, median m (IQR) b | 1.71 (1.67–1.82) | NA |
| Challenge dose, mean Log10 a | 4.27 (±0.07) | 4.30 (±0.06) |
| Typhoid diagnosed, n (% of study) b | 20 (66.6) | 13 (65) |
| Days to typhoid diagnosis, median number (range) b | 7 (5–11) | 8 (5–10) |
| Hemoglobin, b | 14.1 (±1.6) | 14.0 (±1.3) |
| Mean Corpuscular Volume (MCV), b | 91.06 (± 4.61) | 90.61 (±4.79) |
| Hematocrit, b | 0.428 (±0.043) | 0.428 (±0.037) |
| Platelets, b | 248.5 (±64.9) | 226.5 (± 38.9) |
| White cell count, b | 6.2 (±1.8) | 6.5 (±2.3) |
| Neutrophils, b | 3.40 (±1.38) | 3.59 (± 2.16) |
| Lymphocytes, b | 2.01 (±0.65) | 2.09 (± 0.59) |
| Eosinophils, b | 0.21 (±0.11) | 0.29 (± 0.15) |
| Serum Iron, μmol/L, b | 12.3 (±5.6) | 14.9 (±5.2) |
| Total Iron Binding Capacity (TIBC), μmol/L a | 56.3 (±7.2) | 51.8 (±8.2) |
| Transferrin saturation (Tsat), %, a | 22.3 (±10.6) | 29.0 (±9.4) |
| Log10 ferritin, μg/L, b | 1.61 (0.38) | 1.71 (0.37) |
| Log10 hepcidin, ng/mL, b | 1.01 (0.34) | 1.1 (0.28) |
| Log10 CRP, mg/L b | 0.10 (±0.51) | -0.29 (±0.57) |
a p<0.05, t test
b p>0.05
c arithmetic mean (+/- standard deviation) reported unless stated otherwise.