Prevalence of and risk factors for hepatitis B virus infection among street-recruited young injection and non-injection heroin users in Barcelona, Madrid and Seville.

ABSTRACT

BACKGROUND: To evaluate the prevalence of hepatitis B virus (HBV) and associated factors in 949 heroin users (HU) injectors (IHUs) and non-injectors (NIHUs). METHODS: Cross-sectional study; structured questionnaire administered by computer-assisted personal interviewing and audio computer-assisted self-interviewing; dry blood samples analysed for the hepatitis B core antigen and hepatitis B surface antigen; bivariate analysis and logistic regression. RESULTS: The prevalence of infection was significantly higher in IHUs (22.5%) than in NIHUs (7.4%) in the three cities. In the logistic analysis of male IHUs, infection was found to be associated with living in Seville, age over 25, foreign nationality, having had a sexual partner who traded sex, hepatitis C virus infection, and having injected for more than 5 years. In female IHUs, HBV infection was associated with age over 25, having injected as the first main route of administration, and having begun to inject before 18 years of age. In NIHUs, the associated factors were female gender, foreign nationality and having been tattooed. In young IHUs, the prevalence of HBV infection remains four times higher than in the general population of the same age group. CONCLUSION: The vaccination strategy urgently needs to be reinforced and redesigned to achieve acceptable control of the HBV infection in the most vulnerable groups, with special attention to immigrants.