Project Summary/Abstract Implementing effective prehospital medical care could prevent over half of injury-related deaths. As a first step toward development of prehospital care systems, several low- and middle-income countries (LMIC) in sub- Saharan Africa (SSA) have instituted lay first responder (LFR) programs training non-medical professionals with high exposure to injury in first aid and safe transport of injured patients. Although promising, lack of research infrastructure and medical records in SSA has limited prior evaluation of the feasibility and effectiveness of LFR implementation in increasing quality prehospital care. Cameroon is disproportionately affected by injury and lacks a prehospital care system, likely contributing to treatment delays and preventable morbidity and mortality. Development of a lay first responder program could increase access to prehospital care and facilitate timely treatment of injuries but only if it is feasible and effective for the Cameroonian context. The long-term goal of this research is to reduce the burden associated with injury in Cameroon. This study’s overall objective is to increase access to quality prehospital trauma care in Cameroon by using an implementation science approach to develop and evaluate a data-driven LFR program in Cameroon. The study hypothesis is that is implementation of a data-adapted lay first responder program is a feasible and effective method of increasing access to prehospital care among injured Cameroonian patients. To accomplish our objective, this study will pursue three specific aims: 1) Develop a Cameroon-adapted LFR program using a two-stage, mixed-methods approach; 2) Evaluate feasibility of LFR program implementation in the Cameroonian context; and 3) Evaluate effectiveness of LFR program implementation in the Cameroonian context. Validating LFR as a feasible means to increase access to prehospital care will remove a major roadblock in delivering timely trauma care and provide a critical target for reducing the detrimental impact of injury on this population. Understanding associations between LFR implementation, physiologic parameters and outcomes will allow data-informed, iterative improvement of LFR training. Development of a reproducible method for context-adaptation of LFR could be rapidly scaled for wider implementation throughout Cameroon and validated in other LMIC contexts and sectors.