Injecting and HIV prevalence among young heroin users in three Spanish cities and their association with the delayed implementation of harm reduction programmes

Objectives: To evaluate changes in the prevalence of HIV infection among young heroin users in three Spanish cities, and their association with harm reduction programmes (HRPs). Methods: Two cross sectional studies. The 1995 study included 596 users; half were street recruited and half were recruited at drug treatment centres. The 2001-03 study included 981 street recruited users. Face to face interviews were conducted using a structured questionnaire. Samples for HIV testing (saliva in 1995 and dried blood spot in 2001-03) were collected. Results: The proportion who had ever injected (IDUs) decreased in all three cities. HIV prevalence in IDUs decreased by half in Barcelona (44.1% to 20.8%) and Seville (44.2% to 22.2%), but remained constant in Madrid (36.8% and 34.9%). This difference was attributable to a decrease in HIV prevalence in long term IDUs in Barcelona and Seville, but not in Madrid. The crude odds ratio for HIV prevalence in Madrid compared with Barcelona in long term IDUs was 2.3 (95% CI 1.4 to 3.7), increasing to 3.1 (95% CI 1.5 to 6.2) after adjusting for sociodemographic and risk factors. HIV prevalence in short term IDUs was similar in all cities. In 1992 Barcelona already had 20 heroin users in methadone maintenance programmes (MMPs) per 10 000 population aged 15-49 years; Seville reached this rate in 1994, and Madrid, not until 1998. Conclusions: The prevalence of HIV infection did not decrease in long term injectors in Madrid. The delayed implementation of HRPs, especially MMPs, may be the most plausible hypothesis. This finding should shed light on decision making in countries in a similar epidemiological and sociological situation.