AbstractBackgroundStudies of implementation of efficacious human immunodeficiency virus (HIV) prevention interventions are rare, especially in resource-poor settings, but important, because they have the potential to increase the impact of interventions by improving uptake and sustainability. Few studies have focused on provider and organizational factors that may influence uptake and fidelity to core intervention components. Using a hybrid design, we will study the implementation of an efficacious intervention to reduce sexually transmitted infections (STIs) among female sex workers (FSWs) in 12 cities across Mexico. Our protocol will test a 'trainthe- trainer' implementation model for transporting the Mujer Segura (Healthy Woman) intervention into community-based organizations (CBOs).MethodsWe have partnered with Mexican Foundation for Family Planning (Mexfam), a nongovernmental organization that has CBOs throughout Mexico. At each CBO, trained ethnographers will survey CBO staff on characteristics of their organization and on their attitudes toward their CBO and toward the implementation of evidence-based interventions (EBIs). Then, after CBO staff recruit a sample of 80 eligible FSWs and deliver a standardcare, didactic intervention to 40 women randomly selected from that pool, a Mexfam staff person will be trained in the Mujer Segura intervention and will then train other counselors to deliver Mujer Segura to the 40 remaining participating FSWs. FSW participants will receive a baseline behavioral assessment and be tested for HIV and STIs (syphilis, gonorrhea, and chlamydia); they will be reassessed at six months post-intervention to measure for possible intervention effects. At the same time, both qualitative and quantitative data will be collected on the implementation process, including measures of counselors' fidelity to the intervention model. After data collection at each CBO is complete, the relative efficacy of the Mujer Segura intervention will be analyzed, and across CBOs, correlations will be examined between individual and organizational provider characteristics and intervention efficacy.DiscussionThis cooperative, bi-national research study will provide critical insights into barriers and facilitating factors associated with implementing interventions in CBOs using the 'train the trainer' model. Our work builds on similar scale-up strategies that have been effective in the United States. This study has the potential to increase our knowledge of the generalizability of such strategies across health issues, national contexts, and organizational contexts. Trial registration NCT01465607