Prevalence and incidence rate of HIV, hepatitis B and C among drug users on methadone maintenance treatment in Geneva between 1988 and 1995.

OBJECTIVES

To evaluate the prevalence and incidence rates of infection with HIV, hepatitis B (HBV) and hepatitis C (HCV), in a cohort of drug users (DU) in Geneva, Switzerland.

DESIGN

Prospective open cohort study.

SETTING

Private methadone maintenance treatment (MMT) programme.

PATIENTS, PARTICIPANTS: Over 700 DU in treatment between 1988 and 1995 were tested biannually for HIV, HBV and HCV infection.

INTERVENTION

None.

MAIN OUTCOME MEASURE

Prevalence for HIV, HBV and HCV at study entry, determined by gender, by injection behaviour, by year of start of MMT and incidence rates for HIV, HBV and HCV, assuming equal risk of seroconversion on each day of the interval between last negative and first positive test.

RESULTS

The prevalence at entry into treatment declined dramatically over time for all three viruses. Comparing DU entering treatment before 1988 to those entering treatment after 1993, the prevalence of HIV was 38.2% versus 4.5%, of HBV 80.5% versus 20.1%, and of HCV 91.6% versus 29.8%, respectively. Follow-up rate was 80%. The incidence rates for HIV and HBV were 0.6% and 2.1% per person-year of follow-up, respectively. For HCV the rate was higher (4.2%) especially among women (9.6%).

CONCLUSION

These data suggest that DU have changed HIV risk-taking behaviour in response to HIV prevention campaigns. Current prevention efforts should focus on improvement of HCV prevention, identification of high-risk individuals and maintaining safe behaviour.