Cultural Adaptation of Together+, a Status-Neutral mHealth Intervention to Improve HIV Prevention and Care for Adolescent and Young Men Who Have Sex With Men in Vietnam: Protocol for a Co-Design Study

Adolescent and young men who have sex with men (AYMSM) are experiencing an ongoing epidemic in Vietnam. HIV testing and preexposure prophylaxis uptake among AYMSM remain low in Vietnam, especially compared to older men. AYMSM living with HIV are also less likely to initiate HIV care. M-Cubed is a status-neutral mobile intervention developed in the United States focusing on HIV prevention and care among men who have sex with men. The app has the potential to significantly contribute to improving the HIV prevention and care continuum for AYMSM. We propose to adapt the M-Cubed app for AYMSM in Vietnam to create Together+, a status-neutral app that promotes HIV testing, preexposure prophylaxis use, and HIV care. Adaptation will focus on ensuring that the content, features, and design of the app are culturally relevant to AYMSM in Vietnam. The adaptation process will comprise five phases: (1) adaptation and creation of videos and messages in Vietnamese, (2) in-depth interviews to further inform app adaptation, (3) app prototype development, (4) app theater testing, and (5) beta testing of the adapted app. AYMSM aged between 15 and 19 years and health care staff in Hanoi, Vietnam, will be recruited for in-depth interviews in phase 1 and focus group discussions in phase 4. Qualitative data will be analyzed thematically, and results will be generated after reviewing memos, code reports, and the matrix. To evaluate the feasibility and usability of the Together+ app, we will provide access to 30 AYMSM and encourage them to use the app for 30 days. We will assess observed use and collect quantitative and qualitative data from test users. After 30 days, we will evaluate the usability and feasibility of the Together+ app through in-app analytics as well as online quantitative surveys and individual exit interviews with participants. As of September 2025, we are in the process of adapting the set of 15 videos for Vietnamese AYMSM (phase 1) and analyzing qualitative data from in-depth interviews (phase 2). Data collection for the pilot phase will be completed by August 2026. Adaptations of proven effective interventions are a promising and efficient way to develop interventions for new service populations but require formal adaptation and evaluation in the new service population. Once culturally adapted for AYMSM in Vietnam, the Together+ app has the potential to significantly contribute to improving the HIV prevention and care continuum for this population. The findings of the adaptation process will document the level of usability and feasibility of the Together+ app and shed light on the perceptions of AYMSM and other stakeholders in Vietnam regarding status-neutral mobile health interventions. PRR1-10.2196/73895