[Anonymous and free-of-charge detection of human immunodeficiency virus infection. 20-months' experience at a center].

The results of 20 months' activity of the anonymous and free-of-charge detection centre of the Pitié-Salpêtrière hospital group, Paris, concerning human immunodeficiency virus infection (HIV) are presented. During that period, 3,480 persons consulted and 3,332 anonymous questionnaires were filled and returned: 20.5 percent of the subjects were homosexuals, 6.5 percent were drug-addicts and 73 percent were non drug-addict heterosexuals; 31 percent used condoms. A total of 3,398 blood samples were collected; 232 sera were positive or undetermined for HIV-1 and/or HIV-2 by the ELISA method; 132 Western Blot tests confirmed the positivity for HIV-1 but not for HIV-2. The overall serum positivity was 4 percent; 18.3 percent of drug-addicts, 9.5 percent of homosexuals and 0.9 percent of heterosexuals were HIV positive. Among seropositive subjects, 51 percent were homosexuals, 27 percent were drug-addicts, 4 percent were homosexual drug-addicts and 18 percent were heterosexuals (43 percent of these had had multiple partners); condoms were used by 59 percent of HIV positive subjects. The percentage of HIV positive subjects in our series was lower than that estimated in populations at risk (drug-addicts 50 percent, homosexuals 32 percent); it was similar to the percentages found in other detection centres (5 to 6 percent). Most seropositive patients belong to the category of persons who are the first to be struck by HIV. The heterosexual population is relatively spared, but most of the recent seroconversions have occurred in this group.