Heterosexual HIV Transmission Study (HATS)

In the United States, the number of AIDS cases attributed to heterosexual transmission, although still a small percentage of the total number of reported cases, is the most rapidly growing category. The rate at which HIV is transmitted between heterosexual couples and the factors that may impede or enhance heterosexual transmission are important to understanding and slowing the worldwide HIV epidemic. This epidemiologic study is composed of three parts. PART A: In a prospective study, heterosexual couples who are discordant with respect to HIV infection will be evaluated at 6-month intervals to determine whether HIV transmission has occurred and to identify biological and behavioral factors associated with HIV transmission from the infected partner to the uninfected partner. PART B: A case-control study will compare behavioral and biological data from heterosexual couples who are concordant for HIV infection at study entry with data from appropriate discordant couples enrolled in the prospective study. "Cases" will be HIV-infected secondary partners (from concordant couples) and "controls" will be uninfected secondary partners (from discordant couples). PART C: In a cross-sectional study, semen and cervico-vaginal washings will be collected from HIV-infected men and women in Parts A and B and evaluated for presence of HIV by virologic and serologic methods. Members of each couple will be interviewed separately by different interviewers. Demographic, sexual behavior and drug use history, and psychosocial information will be obtained. Participants will undergo clinical examination and various diagnostic laboratory tests (e.g., blood tests, urine screening, and gynecological tests). They will receive post-test counseling.