Abstract
BACKGROUND: Frontline professionals are routinely exposed to acute and cumulative occupational stressors that are associated with an elevated risk of psychological distress, burnout, and trauma-related difficulties. Digital mental health interventions offer scalable and flexible approaches to supporting psychological well-being in high-demand occupational environments. However, there remains limited empirical evidence regarding the feasibility and cultural adaptation of trauma-informed digital interventions across diverse international contexts. OBJECTIVE: This protocol describes a multi-country feasibility study to co-create, translate, localize, and evaluate the usability and acceptability of Sentinel, a trauma-informed digital mental health intervention designed for frontline and trauma-exposed occupational groups. METHODS: The study will be conducted across implementation sites in Saudi Arabia, South Africa, and Ukraine. Sentinel is delivered as a self-guided, modular digital intervention structured around 4 conceptual domains: recognize, remedy, recover, and resilience. Preparatory phases include stakeholder engagement, linguistic validation, and contextual localization. A 6-week single-arm feasibility pilot will be undertaken with approximately 100 frontline professionals recruited at each international site. Primary feasibility outcomes will focus on usability and acceptability, assessed through engagement analytics, Mobile App Rating Scale scores, and qualitative user feedback. Secondary exploratory outcomes will include preliminary indicators of psychological well-being, perceived psychological safety, and coping responses. Feasibility progression criteria will include recruitment and retention thresholds, patterns of intervention engagement, usability ratings, and qualitative indicators of cultural relevance to inform optimization prior to future controlled evaluation. RESULTS: Preparatory study activities commenced in early 2026, including the development of international research partnerships and planning for stakeholder engagement and translation procedures. Ethical approval applications are scheduled for submission between June and September 2026. Participant recruitment is anticipated to begin in October 2026, with feasibility pilot data collection expected between November 2026 and March 2027. Quantitative and qualitative analyses are planned for April to June 2027. No outcome data are available at the time of manuscript submission. CONCLUSIONS: This study will generate evidence regarding the feasibility, usability, and cultural adaptation of a trauma-informed digital mental health intervention for frontline professionals across diverse socio-cultural settings. Findings will inform the iterative refinement of the intervention and guide progression to future effectiveness trials and wider implementation.