Table 1.
Oxford challenge studies: clinical parameters.
| Study | Typhoid challenge (N = 23) | Paratyphoid challenge (N = 40) | ||
|---|---|---|---|---|
| Challenge agent, strain | S. enterica serovar Typhi, Quailes strain | S. enterica serovar Paratyphi A, strain NVGH308 | ||
| Participants included in ALS analysis (type) | Challenge and diagnosed participants only | All challenged participants | ||
| Challenge dose level | Low | High | Low | Lower |
| Target dose | 1–5 × 103 | 10–50 × 103 | 1–5 × 103 | 0.5–1.0 × 103 |
| Actual dose, median [range] | 1.05 × 103 [0.7–1.8] | 19.8 × 103 [15.5–27.0] | 2.40 × 103 [2.2–2.8] | 0.91 × 103 [0.7–1.3] |
| Number assessed | 11 | 12 | 20 | 20 |
| Male sex, N (%) | 11 (100) | 7 (58) | 10 (50) | 11 (55) |
| Median age, yrs [range] | 27 [19–41] | 28 [20–44] | 28 [19–49] | 28 [23–50] |
| Attack rate, N (%) | na | na | 12 (60) | 8 (40) |
| Median time to diagnosis, days [IQR] | 11 [7–13] | 8 [6–9] | 6 [6–7] | 8 [8–9] |
| Mode diagnosis, n(%) | ||||
| Temperature criterion | 6 (60) | 7 (58) | 1 (9) | 0 (0) |
| Blood culture criterion | 4 (40)* | 5 (42) | 11 (81) | 8 (100) |
| ≥1 positive blood cultures, N (% diagnosed) | 9 (90)* | 10 (83) | 12 (100) | 8 (100) |
| Median duration bacteraemia, days [IQR] | 1 [1–2] | 2 [1–3] | 4 [2.5–5] | 1 [1–4.5] |
| Median temperature at diagnosis, °C [IQR] | 37.9 [36.7–38.7] | 37.8 [37.3–38.1] | 37.4 [36.9–38.0] | 36.9 [36.5–37.3] |
| Median heart rate at diagnosis, bpm [IQR] | 96 [79–109] | 95 [83–104] | 87 [80–92] | 83 [79–89] |
| Typhoid symptom triad*, N (%) | 11 (55) | 12 (75) | 6 (30) | 3 (15) |
*
Typhoid symptom triad = fever, headache plus abdominal pain. na, not applicable.