Table 3. Incidence rate and preventable fraction of hepatitis A cases associated with reported person-to person outbreaks according to risk factor of the index case.
| Risk factor | Incidence rate* Period 1: 1991–98 (95%CI) |
Incidence rate* Period 2: 2000–12 (95%CI) |
Incidence rate* gPeriod 1+Period 2 (95%CI) |
Preventable fraction** (95%CI) |
|---|---|---|---|---|
| Household contact | 0.059 (0.040–0.085) |
0.066 (0.050–0.084) |
0.063 (0.051–0.078) |
- |
| Day-care contact | 0.023 (0.011–0.040) |
0.018 (0.010–0.028) |
0.019 (0.013–0.028) |
9.08 (< 0–37.52) |
| School contact | 0.047 (0.030–0.071) |
0.019 (0.011–0.030) |
0.029 (0.020–0.039) |
34.79 (11.29–59.30) |
| Immigrant | 0.010 (0.003–0.024) |
0.063 (0.048–0.082) |
0.045 (0.035–0.057) |
|
| Travel | 0.002 (0.000–0.011) |
0.005 (0.002–0.013) |
0.004 (0.002–0.009) |
|
| MSM | - | 0.028 (0.019–0.042) |
0.019 (0.012–0.027) |
MSM, men who have sex with men; CI, confidence interval; *per 100,000 persons-year; **in percentages. Only calculated if a decrease was observed