A continuing concern: HIV and hepatitis testing and prevalence among drug users in substitution programmes in Zurich, Switzerland

Phase I of the Zurich Prometheus Study is a cross-sectional study focusing on an up-to-date serology for HIV and hepatitis B/C and associated risk fac tors for all clients in four participating clinics offering opiate substitu tion in Zurich, Switzerland. The mean age of the 603 respondents is 30. 7 y ears (SD = 6.2) and 38% of them are women. Seventy-five per cent of the res pondents have a history of injecting drug use (IDU), and over half have inj ected within the past six months. Laboratary-confirmed seroprevalence for H BV (50%) and HCV (57%) is twice that of HIV (24%). There is an 80% risk red uction for all three viral infections among those starting IDU after 1991-w hen harm reduction efforts were in full swing-compared to those who began b efore 1988-before clean needles were widely available. These findings sugge st a strongly protective effect of harm reduction measures. But while a sta bilization in HIV/prevalence at 15% can be seen among drug users who starre d injecting after 1991, prevalence rates for HBV and HCV still remain sever al times higher. The prevalence data in this study support data showing con tinued high incidence rates for HBV and HCV, even among new injectors in th e harm reduction era.