Effects of a Sequential Community-Based Multi Component HIV Intervention on Sexual Behavior, Drug Use and Syringe Sharing for People Who Inject Drugs on the US-Mexico Border: A Quasi-Experimental Study.

People who inject drugs (PWID) are disproportionately impacted by HIV. To end the HIV epidemic, it is necessary to implement interventions that mitigate the risk of HIV transmission among priority populations. We implemented and tested a community-based intervention for PWID informed by a community based participatory approach in two sister cities on the US-Mexico border. The intervention consisted of three components implemented sequentially: social network HIV testing, peer network psychoeducational and skill building intervention, and community wide events to reduce HIV stigma. Using a quasi-experimental design, we evaluated outcomes through cross-sectional surveys at 6- and 12-months post-implementation of each component, focusing on condomless sex in exchange for drugs (primary outcome), and frequency of substance use and syringe sharing (secondary outcomes). For cross-sectional surveys, we recruited 630 PWID using respondent driven sampling (RDS) chain referrals. Outcome analyses indicated significant reductions in condomless sex in exchange for drugs, frequency of substance use, and syringe sharing. Results also indicated that the number of preventative behaviors enacted after participation were influenced by being exposed to peer information dissemination which promoted adoption of harm reduction behaviors and self-efficacy to enact harm reduction behaviors. The community-based participatory research approach proved essential for building trust and ensuring intervention fidelity.