"In 2010, the prevalence rate (per 1000 inhabitants, aged 15-64 years) of ever-IDUs was estimated to be 1.2 (95% CI: 0.78-1.90) and the total number of ever-IDUs in Belgium to be 8,796 (95% CI: 5,717-13,583). The uncertainty in the incidence estimates was large. A sensitivity analysis was carried out, revealing that this uncertainty was primarily due to the uncertainty associated with the estimation of the HIV-prevalence rate among IDUs rather than with the uncertainty resulting from the stochastic mortality model. Time trends of the national prevalence rate of ever-IDUs are graphically presented in Figure 4.3. Partly as a result of the large uncertainty in estimates, no significant time trends were observed. Nevertheless, the results suggest a stabilizing trend in prevalence rate of ever-IDUs from 2006 onwards. The current estimate of 8,796 IDUs in Belgium (95% CI: 5,717-13,583) in 2010 is (borderline not-significantly) smaller than the estimate of 20,000 IDUs (95%CI: 10,300-46,300) from 1995. However, this comparison should be made with caution as a result of methodological differences (age range, (not) accounting for non-AIDS mortality)."


Deprez, Nathalie, et al., "2011 National Report (2010 data) to the EMCDDA by the Reitox National Focal Point" (Brussels, Belgium: OD Public Health and Surveillance, Scientific Institute of Public Health, October 2011), WIV-ISP/EPI REPORTS N° 002, p. 88.