220.7 PROJECT SUMMARY/ABSTRACT Stigma is a pervasive barrier to preventing HIV among persons who inject drugs (PWID). Kyrgyzstan is part of the world’s most rapidly expanding HIV epidemic in the Eastern Europe and Central Asia region, where HIV is predominantly concentrated among PWID. Improving PWID engagement in needle and syringe programs (NSP), methadone to treat opioid use disorder (MMT), and antiretrovirals (ART) to treat HIV (among HIV+ PWID) is essential to ending the HIV epidemic in this region. Substantial qualitative research documents that PWID contend with stigmas related to HIV, drug use, and drug treatment (i.e. methadone), which undermine engagement in these key HIV prevention services. Yet, less is known about which of these intersecting stigmas are most critical to intervene on to improve engagement in HIV prevention services. Further, the focus of intersectional stigma has not been extended to rural PWID in the region despite increased HIV incidence in rural areas. Structural equation modeling–a robust quantitative method–can identify which of these stigmas are most critical to intervene on to optimize engagement in HIV prevention services among urban and rural PWID. The current study will recruit urban (n = 102) and rural (n = 102) adult PWID using respondent driven sampling. Experiences with HIV, drug use, and methadone stigma, and level of engagement in NSP, MMT (primary outcome) and ART (secondary outcome) services will be measured at baseline. Structural equation modeling will be used to identify optimal points to reduce stigma and improve engagement in HIV prevention service s (Aim 1). A follow up assessment will be conducted 3 months post-baseline to obtain study retention estimates and refine protocols for retaining urban and rural PWID in a future efficacy trial (Aim 2). A series of four data-driven and community-informed workshops with PWID (n = 20) and key stakeholders (n =2 0) will be held to develop stigma reduction interventions tailored to urban and rural regions in Kyrgyzstan (Aim 3). Kyrgyz co-investigators will be substantially involved at every level of this project to build in-country capacities in stigma and HIV science. This will enable our Kyrgyz team to develop the next generation of research scholars in a region where the HIV epidemic is rapidly expanding, and the incidence of AIDS-related mortality is climbing. This project will lay the groundwork to implement a future stigma reduction intervention among urban and rural PWID in Kyrgyzstan. As the first study to quantify the impact of intersecting stigmas (HIV, drug use, methadone) on HIV prevention among urban and rural PWID, this study is significant because stigma is a key sociostructural driver of a rapidly expanding HIV epidemic in EECA–due to low engagement in HIV prevention services (including HIV treatment). This study is highly innovative because it reflects a substantial departure from how intersecting HIV, drug use, and methadone stigma has b...