Table 2.
Incidence Rates by Serological Test Result
| HIV | Hepatitis B | Hepatitis C | |
|---|---|---|---|
| Number of susceptible individuals at baseline | 442 | 199 | 267 |
| Number (and percent) of susceptible individuals with follow-up | 190 (43.0%) | 67 (33.7%) | 99 (37.1%) |
| Number of seroconversions | 1 | 1 | 11 |
| Total exposure time (months)* | 3062.4 | 962.5 | 1461.7 |
| Incidence rate (per 100 person-years) | 0.39 | 1.25 | 9.03 |
| 95% Confidence interval | 0.01 – 2.16 | 0.22 – 6.69 | 5.14 – 15.29 |
Exposure time was measured as the number of months between baseline and follow-up visits for study participants negative for a given viral infection at baseline. For those who seroconverted, half of the period between baseline and first seropositive visit was used in calculating total exposure time.