HIV seroprevalence among homeless and marginally housed adults in San Francisco

Objectives. We report HIV seroprevalence and risk factors for urban indigent adults. Methods. A total of 2508 adults from shelters, meal programs, and low-cost hotels received interviews, blood tests, and tuberculosis screening. Results. Seroprevalence was 10.5% overall, 29.6% for men reporting sex with men (MSM), 7.7% for non-MSM injection drug users (IDUs), and 5.0% for residual non-MSM/non-IDUs. Risk factors were identified for MSM (sex trade among Whites, non-White race, recent receptive anal sex, syphilis), non-MSM IDUs (syphilis, lower education, prison, syringe sharing, transfusion), and residual subjects (greater than or equal to 5 recent sexual partners, female crack users who gave sex for drugs). Conclusions. HIV seroprevalence was 5 times greater for indigent adults than in San Francisco generally. Sexual behavior predicted HIV infection better than drug use, even among IDUs.