The primary objective of the study is to evaluate and compare, in at-risk populations, the efficacy of three different counseling methods in terms of propensity to come back for a HIV re-test. Secondary objectives are to evaluate and compare the efficacy of the counseling methods in terms of reported risk behavior and HIV knowledge as well as their acceptability and cost-effectiveness, describe the distribution of duration from HIV primary infection to detection, and estimate the prevalence of chronic hepatitis B and C, and syphilis in HIV-uninfected participants of targeted populations.