In pursuit of a one-stop shop: a hybrid type 1 effectiveness-implementation trial of comprehensive tele-harm reduction for people who inject drugs - ABSTRACT People who inject drugs (PWID) remain a high priority population under the Ending the HIV Epidemic: Plan for America (EHE) with 11% of new HIV infections attributable to injection drug use (IDU). IDU has led to multiple recent outbreaks of HIV in the US, driven primarily by the ongoing opioid and stimulant crises, creating an obstacle in meeting EHE goals of a 90% reduction in incident HIV infections by 2030 through the 4 pillars – diagnose, treat, prevent, and respond. EHE has identified evidence-based interventions within these pillars, including rapid HIV testing, antiretrovirals, comprehensive syringe services programs (SSPs), and PrEP that need to be implemented, scaled, and sustained within communities most affected by HIV. To maximize and extend the effectiveness of these interventions among PWID, differentiated, simplified, integrated, and comprehensive healthcare models need to be developed, tested, and deployed where they are in comfortable, destigmatizing environments that simultaneously address a key driver of HIV—substance use disorder (SUD). In addition to HIV, PWID continue to be impacted by a myriad of harmful health conditions such as hepatitis C virus (HCV), overdose, bacterial infections and sexually transmitted infections (STIs) due to structural, economic, social, and policy constraints. PWID often experience discrimination, stigma, and considerable social disadvantage, leading to almost universal poorer health outcomes than comparable populations who do not inject drugs. The need for innovative, efficacious, scalable, and community-driven models of healthcare in destigmatizing settings for PWID is crucial. Our team has led the development and testing of Tele-Harm Reduction (THR): a telehealth-based, multicomponent, adaptive care model for PWID living with HIV. Building on this work, we now seek to rapidly adapt and test Comprehensive-THR (C-THR) for comprehensive HIV prevention services delivered via an SSP. We propose a hybrid type I effectiveness-implementation randomized controlled trial (n=350) to evaluate the efficacy of the C-THR model vs. offsite referral and peer navigation for engagement in HIV prevention (i.e., PrEP or medications for OUD). PWID will be recruited from an academic medical center-based syringe services program (SSP) in Miami, FL (IDEA Miami) from both fixed and mobile SSP modalities. There are three overall aims of the proposed study: (1) to determine if the C-THR model increases engagement in HIV prevention compared to offsite referral and peer navigation, (2) to examine the long-term clinical and cost-effectiveness of the C-THR model, and (3) to assess the implementation and scalability of the C-THR model in diverse SSP settings. The co-primary outcome is tenofovir on dried blood spot or buprenorphine on urine drug screen across follow-up at 3,6,9 and 12 months. Secondary outcomes will include engagement in HIV/HCV/STI testing and sustained virologic response (SVR, cure) for HCV. The cost- effectiveness analysis, long-term modeling, and mixed-methods implementation and scalability evaluation will provide compelling data on the sustainability and possible impact of C-THR on comprehensive HIV prevention delivered via SSPs in the COVID era and beyond.