Evaluation of the impact of Dublin's expanded harm reduction programme on prevalence of hepatitis C among short-term injecting drug users.

Injecting drug users represent a high risk group for hepatitis C virus (HCV) infection and, in many locations, the majority will test positive for antibody to HCV (anti-HCV) within two years of starting to inject. Although there is evidence of a reduction in rates of unsafe injecting, 3 there is little published research demonstrating that programmes that facilitate safe injecting have reduced the occurrence of HCV. Consequently, some commentators are not optimistic that we will see a decrease in HCV prevalence among injecting drug users. Harm reduction programmes include methadone treatment, education regarding safer injecting and the provision of syringe exchange. These services vastly expanded in Dublin over the period 1991 to late 1993. The number of syringe exchange centres increased from two to eight and the number of community outreach workers and addiction counsellors increased by 74%. We sought to test the hypothesis that, among injecting drug users with short injecting histories, the prevalence of HCV would be lower in those who started injecting during the period after this expansion in services. The setting for this study was Trinity Court, which is the largest and longest established addiction treatment centre in Dublin. Services provided include counselling, methadone maintenance and detoxification and assessment regarding medical problems associated with drug use such as HCV. Patients, Method, and Results Data have been recorded on an ongoing basis on the results of all HCV tests on injecting drug users attending Trinity Court since 1992. In this study, consecutive new attenders, resident in Dublin, with a reported injecting history less than 25 months, tested for anti-HCV between July 1993 and December 1996 were included. We used a third generation enzyme linked immunosorbent assay for anti-HCV ( Ortho Clinical Diagnostics, Amersham, England). Positive results were confirmed with a further third generation test. In all 353 injecting drug users were tested. The primary drug of choice was heroin for 78%, morphine sulphate for 21%, and benzodiazepines for 1%. Those with injecting histories of less than 13 months were over-represented in the group that started injecting in the period after January 1994 (75.1% v 46.5%, ÷ =30.4, p<0.001) and they were more likely to misuse heroin (86.2% v 68.6%, ÷ = 15.7, p< 0.001). Period of commencement of injecting was not significantly associated with age, sex, employment or injecting status of sexual partner (÷ tests). The prevalence of anti-HCV was 52.1%. Univariate analysis showed that those who started injecting in the period after January 1994 ( post-1993 group) and those with injecting histories of less than 13 months demonstrated significantly reduced risks of HCV infection (see table 1). Age over 21 years was weakly associated with increased risk.