Using a 2-Stage Strategy with Respondent-Driven Sampling to Recruit a Hard-to-Reach Population for a Placebo Microbicide Gel Clinical Trial in Nellore, Andhra Pradesh (India).

Traditional recruitment methods for microbicide efficacy trials are labor intensive and may fail to reach high-risk hard-to-reach populations. We report duration of recruitment and lessons learned from a two-stage process to recruit female sex workers (FSWs) into a placebo microbicide trial, and examined characteristics associated with successful recruitment of peers who screened for and enrolled in the trial. FSWs were first recruited via respondent-driven sampling (RDS) to complete a survey and subsequently invited to screen for enrollment into a placebo microbicide trial taking place at a local clinic. It took 6 months to enroll 267 participants into the trial. Successful recruiters of peers who enrolled were more likely to have enrolled themselves (AOR 2.0, CI 1.3-2.9) and less likely to visit Nellore city (AOR 0.5, CI 0.3-0.9). Recruitment of FSWs via a two-stage recruitment strategy with RDS can be a good option for future clinical trials. [ABSTRACT FROM AUTHOR]