Evaluating Vending Machines providing Naloxone to Prevent Overdose in American Indian Communities - Project Summary American Indian communities have been greatly affected by the opioid epidemic with many Tribes being overwhelmed by opioid use and overdose. Among all racial/ethnic groups in the U.S., American Indians and Alaska Natives have the highest rate of overdose fatalities from all opioids. Within Southern California, areas encompassing American Indian Tribes have experienced some of the highest age-adjusted rates of opioid overdose deaths. In March 2023, the Harm Reduction Coalition of San Diego (HRCSD) formed strategic partnerships with Southern California Tribes to install overdose prevention vending machines (ODPVM) that freely dispense naloxone, with the goal of reducing opioid-related overdose deaths on tribal reservations. To our knowledge, these are the first ODPVM to be established on Tribal Sovereign Land in the U.S. With the current or soon-to-be placement of ODPVMs on several tribal reservations, our research team, led by two American Indian Principal Investigators, is in a unique position to conduct timely applied research that is responsive to tribal leadership's call for community-based prevention activities aimed at reducing overdose deaths. Through a collaborative community-based and participatory research (CBPR) approach we will conduct a bi-phasic, milestone-driven R61/R33 study over a 3-year period. Our study will focus on the implementation process of ODPVM on tribal lands using the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation and Maintenance), with a focus on health equity. During year 1, the exploratory R61 phase, the study will be guided by the following specific aims: 1. develop the CBPR infrastructure by identifying and working with tribal and community representatives who will aid in the development of a culturally appropriate study design to examine the implementation of ODPVM on tribal lands and 2. identify the initial reach of ODPVM during the first year of vending machine placement. During years 2-3, the developmental R33 Phase, our specific aims will address the following: 3. describe the implementation process and identify implementation strategies to increase utilization of ODPVMs within tribal reservations and 4. compare the impact of ODPVMs by examining the statistical and spatial distribution of fatal overdose rates on tribal reservations vs San Diego County, California. Opportunities to evaluate harm reduction strategies on tribal lands are rare but urgently needed for American Indians. Timely research to evaluate the implementation of ODPVM in real-time will allow key questions to be addressed about approaches, activities, and processes that lead to ODPVM uptake. The knowledge gained from this work will provide crucial preliminary hypothesis- generating data on facilitators to ODPVM uptake and inform a larger scale study to test implementation strategies for effectively implementing ODPVMs within Tribal Sovereign Nations.