Table 2.
Occupational exposures and QFT results stratified by type of medical trainee.
| Occupational exposures | Medical students | Nursing students |
|---|---|---|
| Mean number of exposures (in days or minutes) per 6 months between QFT tests | ||
| Days exposed to smear positive TB patients | 0.94 (SD*: 1.74) Range: 0–9 | 12.4 (SD: 17.7) Range: 0–126 |
| Days spent working on medical wards | 15.5 (SD: 15.1) Range:0–180 | 80.9 (SD: 75.8) Range:0–180 |
| Days exposed to TB patients NOT on anti-TB therapy (ATT) | 0.23 (SD: 0.88) Range:0–7 | 4.5 (SD: 6.58) Range:0–54 |
| Time (in minutes) exposed to smear positive patients | 56.7 (SD: 104.47) Range:0–540 | 185.6 (SD: 265.4) Range: 0–1890 |
| Any TB exposures in hospital prior to enrollment n/N (%) | 192/660 (29.1%) | 180/420 (42.9%) |
| Any TB exposures in the community prior to study enrollment n/N (%) | 68/660 (10.3%) | 24/420 (5.7%) |
| QFT outcome | QFT positivity and conversions – n/N (%)** | |
| Initial QFT positivity | 44/160 (27.5%) | 20/66 (30.3%) |
| QFT conversion rate (at any time point) | 54/307 (17.6%) | 9/134 (6.7%) |
| QFT reversion rate (at any time point) | 35/119 (29.4%) | 9/65 (13.9%) |
*
SD: standard deviation
**
For this analysis each period (i.e., QFT1 to QFT2 or QFT2 to QFT3) was treated as a separate and independent event. Therefore, denominators represent the number of eligible participants at each time point to convert or revert. In order to be eligible for conversion, participants must have had a negative QFT on the previous test; therefore denominators are the number with negative QFT at the start of the interval. To be eligible for a reversion, participants must have had a positive QFT result on the previous test.