During this 5-year study, stepped-care adaptive interventions will be deployed in three rural syringe service programs in a Sequential Multiple Assignment Randomized Trial (SMART) design to test the optimal intervention pathways for HIV PrEP uptake, defined as PrEP initiation (measured by dispensed prescription for oral PrEP) and persistence in PrEP care (measured by refill verification and biomarker confirmation). The study will be accomplished through three Specific Aims. AIM 1: Compare the relative effectiveness of adaptive interventions (AIs) that begin with Peer-led SBCM-PrEP versus those that begin with CDC-PrEP education plus text messaging (TM) on patient-level PrEP care outcomes (initiation and persistence) at 1-, 3- and 6-months; AIM 2: Estimate and rank the effectiveness of four embedded AIs on PrEP care outcomes at 3- and 6-months: (1) CDC-PrEP education, continue TM for responders, add Mobile Outreach for non-responders (NR); (2) CDC-PrEP education, continue TM for responders, add Peer transitional SBCM for NR; (3) Peer-led SBCM-PrEP, continue TM for responders, add Mobile Outreach for NR; (4) Peer-led SBCM-PrEP, continue TM for responders, add Peer transitional SBCM for NR. AIM 3: Across interventions, examine the effects of age, baseline injection frequency, perceived HIV risk, PrEP interest, SSP utilization patterns, and other factors, in predicting PrEP care outcomes at 1-, 3- and 6-months to inform optimally-tailored intervention strategy recommendations.

Kentucky's HIV epidemic displays an especially profound and disproportionate impact among people who inject drugs (PWID): 14.8% of males and 54.2% of females newly diagnosed with HIV in 2021 have an injection drug use-related transmission factor, far exceeding the national average for this exposure category. A central pillar of Ending the HIV Epidemic (EHE) is the prevention of new HIV infections through scale up of Pre-Exposure Prophylaxis (PrEP) in key populations, including PWID. For PWID, PrEP uptake remains severely limited, and no evidence-based PrEP interventions specifically targeted for PWID are available. In the previous pilot in KY's Appalachian region, two brief, low-intensity interventions to promote linkage to co-located PrEP care in rural syringe service programs (SSPs) were successfully implemented, including a newly adapted strengths-based case management (SBCM-PrEP) intervention designed to address multi-level barriers to PrEP initiation. The pilot trial has demonstrated proof of concept for integrated PrEP care within rurally-located SSPs and high acceptability among PWID with high uptake of initial clinical interventions. Nevertheless, just 51% returned for test results, and 28% progressed to PrEP prescription, indicating that augmented intervention support is required to optimize PrEP uptake. The stepped-care Adaptive Interventions (AIs) to be tested respond directly to identified challenges in the pilot trial and the need for augmented support among initial non-responders. AIs have shown remarkable promise in diverse behavioral and medical conditions, including areas such as chronic lower back pain, risky drinking and violent behavior, reducing alcohol use, preventing suicidal behavior, and HIV treatment retention

Inclusion Criteria:

• self-report of at least one occasion of injection drug use in the past month
• use of the SSP in the past 30 days
• expressed willingness to participate in a multi-session intervention and follow-up
• having an indication for PrEP in the past 6 months based on CDC guidelines

Exclusion Criteria:

• being HIV positive
• current PrEP care
• self-reported severe renal impairment and/or chronic HBV infection

All Aim 1 and 2 de-identified REDCap survey data and clinical data extracts from report forms will be preserved and shared. We will not share participant locator information. Datasets will be shared as CSV files.

The study team will submit a de-identified and cleaned survey and clinical dataset within 12 months after the last participant's study visit, or at acceptance of the primary outcomes paper for publication, whichever is first.

De-identified survey and clinical data will be shared with controlled access in for general research use.