HIV prevalence among foreign- and US-born clients of public STD clinics.

OBJECTIVES We examined differences in HIV seroprevalence and the likely timing of HIV infection by birth region. METHODS We analyzed unlinked HIV antibody data on 61 120 specimens from 7 public health centers in Los Angeles County from 1993 to 1999. RESULTS Most (87%) immigrant clients were Central American/Mexican-born. HIV prevalence was similar for US- and foreign-born clients (1.8% [95% confidence interval (CI) = 1.7%, 1.9%] and 1.6% [95% CI = 1.5%, 1.8%], respectively). Seroprevalence was high among sub-Saharan African females and low among Asian/Pacific Islander males and females. For HIV-positive immigrants, the average age at and time since immigration were 20.6 years and 12.3 years, respectively. CONCLUSIONS The relatively young age at arrival and long time since arrival for HIV-positive foreign-born clients suggest that most were infected after immigration.