High rate of HIV seroconversion among patients attending urban sexually transmitted disease clinics.

OBJECTIVE: To study rates of documented HIV seroconversion and syphilis as a cofactor for seroconversion in sexually transmitted disease (STD) clinics. In the main clinic the HIV seroprevalence rate was 12% and most infections had been shown to be acquired by heterosexual contact. METHODS: We analyzed computer records of patients who had at least two HIV-antibody tests between 1 December 1987 and 31 December 1990, at STD clinics in Dade County (Miami), Florida. RESULTS: Of 5164 individuals with two HIV tests, 208 (4.0%) seroconverted. The overall seroconversion rate was 3.1 per 100 person-years. Among blacks, who accounted for 77% of seroconversions, the rate was higher for women (4.8) than for men (2.7). The highest rate was in 15-19-year-old black women (7.1 per 100 person-years). The HIV seroconversion rate was 12.8 for patients with primary or secondary syphilis diagnosed between two HIV tests, 3.1 for patients who acquired syphilis before their first HIV test, and 2.3 for patients who had never had syphilis. Eighteen per cent of all HIV seroconversions were attributable to syphilis acquired in the interval between two HIV tests. CONCLUSIONS: We found high HIV seroconversion rates, especially among black teenagers and black women, in an STD clinic population in which the majority of HIV infections were shown previously to have been acquired heterosexually. Syphilis was a marker for HIV seroconversion and syphilitic ulcers may facilitate HIV transmission. Innovative prevention programs directed towards women and adolescents should be developed and evaluated.