High HIV prevalence in a respondent-driven sampling survey of injection drug users in Tehran, Iran.

Iran is facing unprecedented dual drug use and HIV epidemics. We conducted a cross-sectional survey to obtain HIV prevalence and risk behavior data from injection drug users (IDU) in Tehran. We used respondent-driven sampling (RDS) to recruit IDU through successive waves starting with 24 "seeds," conducted anonymous face-to-face interviews and HIV testing and counseling, and used RDSAT to adjust data.