PROJECT SUMMARY. The parent R01 of this proposed supplement Project SMART (Social Media Anti- Vaping Messages to Reduce ENDS Use Among Sexual and Gender Minority Teens; R01DA054236-01) is to evaluate the effectiveness of an SGM-tailored social media intervention to prevent vaping initiation among SGM youth ages 13-18 years. Scientific Rationale: Although the use of social branding has been utilized in cigarette smoking education campaigns among SGM young adults, this approach has not yet been explored for vaping education campaigns intended for SGM youth. Objectives: The overall objective of this supplement in response to PA-20-272 is to explore strategies used by social media influencers (SMIs) to engage with SGM youth and factors related to collaborating with health organizations in health education campaigns. The long- term goal is to increase the reach and impact of Project SMART's anti-vaping social media intervention to reduce vaping susceptibility and initiation among SGM youth. Based on Social Branding Theory and the Integrative Model of Social Media Influencers (SMIs), our specific aims are to: 1) Explore the strategies SMIs used for content creation and distribution, specifically focusing on social branding efforts to increase message authenticity, relatedness, and credibility and engage SGM youth on social media platforms and 2) Investigate facilitators for SMIs' collaboration with health organizations on future social media-based vaping education interventions for SGM youth, focusing on influencers' interests, motivations, and potential strategies for creating and delivering SGM-tailored vaping prevention messages. Research Strategy: We will first conduct a survey among 100 SMIs to describe influencers' current strategies and prior experiences with creating and distributing health-related social media content that resonate with SGM youth and their interest, motivation, and expectations if they were to partner with health organizations on a vaping prevention campaign for SGM youth. Following the survey data analysis, we will purposively invite 8-10 SMIs from those expressing interest in collaborating on vaping prevention for SGM youth in the survey study for in-depth interviews to explore how SMIs define, implement, and integrate important message and source characteristics into their own post creation and delivery and obtain SMIs' suggestions and recommendations on vaping prevention messages aimed at SGM youth, understand factors SMIs consider like motivations and barriers concerning potential collaboration with researchers and health organizations in co-creating and disseminating effective social media-based vaping prevention messages for SGM youth. Impact: The expected outcomes of this supplement include a detailed understanding of influencers' current strategies for engaging SGM youth on social media platforms, their interest in collaborating on tailored vaping prevention interventions for SGM youth, insights for refining vaping pr...