DECREASING INCIDENCE OF HIV-INFECTION AMO NG INTRAVENOUS-DRUG-USERS -AQUITAINE (SOUTH-WEST FRANCE), 1985-1993

Objective: To describe trends in the incidence of HIV infection diagno sis since 1985 in different at-risk groups in Aquitaine, south-west Fr ance. Methods: We analyzed the data from two regional surveillance sys tems on HIV infection: the hospital-based system of the Groupe d'Epide miologie Clinique du SIDA en Aquitaine (GECSA) and the laboratory-base d system of the Observatoire Regional de la Sante d'Aquitaine (ORSA), The number of intravenous drug users (TVDUs) in Aquitaine was estimate d from two sources: a study performed by the GECSA in IVDUs treatment centers (1990-1991 data) and the annual surveys undertaken by the Mini stry of Health (SESI) in all the health facilities and social services of the region from 1988 to 1993. Results: As of December 31st, 1993, 3478 HIV-infected patients had been reported to the GECSA, including 3 031 Aquitaine residents, Among those, 1096 were TVDUs without any othe r at-risk behavior (36.2%), the largest transmission category, The ann ual incidence of HIV diagnoses has steadily and considerably changed o ver time for IVDUs: 175 new cases diagnosed in 1985, 218 in 1987, then falling to 38 in 1993, During the same period, there was no marked de crease for homosexuals and the incidence of diagnoses of heterosexuall y-acquired HIV infections increased, Between 1989 and 1993, the number of HIV tests performed by the laboratories involved in the ORSA surve illance system increased steadily from 80,310 to 176,250 per year, whe n the number of first positive tests in Aquitaine residents decreased from 744 to 319 per year (-57%), This decrease was greater for IVDUs ( -80%) than for the other groups, The survey performed by the GECSA est imated that 990 IVDUs were followed annually by treatment centres in A quitaine in 1990-1991, This figure was stable and in agreement with th e results of the SESI surveys performed throughout the period. Conclus ion: The incidence of new diagnoses of HIV infection has been decreasi ng in Aquitaine since 1988, particularly among IVDUs, suggesting that the epidemic is slowing down, It is essential to maintain these system s of epidemiological surveillance as a component of the HIV prevention program.