Objective: To describe the time-trend in exposure categories and HIV seroprevalence among adolescents who underwent to voluntary testing in the period 1986-2000.
Methods: This study covered all adolescents, aged 13 to 19 years, at their first test for HIV in a sexually transmitted disease clinic in Madrid. Gender, age and HIV risk behaviours were collected. HIV diagnosis relies on ELISA test and Western blot confirmation. Time trends in HIV seroprevalence and exposure categories were analysed.
Results: A total of 1327 adolescents, 52% women and 22% under 18 years, were studied. The annual number of adolescents remained through the time, but injecting drug users (IDU) and IDU partners declined and female sex workers rose. 108 adolescents were diagnosed with HIV infection -71% were IDU-. HIV seroprevalence was 8.1% -31.3% in IDU-. It declined from 18.2% in 1986 to 1.5% in 1995, and after then it held steady under 4%. This decline involved several risk categories and was statistically significant in homo/bisexual men and female sex workers. The logistic regression analysis, adjusting for changes in exposure categories, showed an annual reduction in HIV seroprevalence (OR = 0.87; 95% CI, 0.81-0.94).
Conclusions: HIV seroprevalence has decreased due to the fall of new young IDU and the decrease of seroprevalence within several exposure categories. HIV infections and risk behaviours continue happened among adolescents.