Project Summary Gay and bisexual men and other sexual minority men (SMM) in the U.S. are burdened by a high and disproportionate rate of HIV infection. Improving outcomes of the HIV Care Continuum through to maintaining viral load (VL) suppression is associated with a significant reduction in the sexual transmission of HIV and significantly better long-term health outcomes. However, little research provides insight into the preventable structural, psychosocial, and behavioral factors that influence VL suppression for the purposes of developing effective early intervention strategies. Moreover, the successful implementation of TasP and U=U messaging is a necessary component of the strategy to end the HIV epidemic, but rigorous research is needed to address the remaining concerns of providers and the general public to ensure their success. Specifically, Aim 1 of the study is to examine time to initial VL suppression and patterns in VL rebound to better understand the dynamic nature of VL suppression and use the Social Ecological Model to longitudinally investigate structural, psychosocial, and behavioral factors associated with VL suppression to better understand risk and resilience. Next, Aim 2 is to examine concordance between perceived and actual VL suppression status and their overlap with event-level sexual behaviors and STI infections to better understand any potential risks of TasP. Finally, Aim 3 will qualitatively examine provider barriers to implementing TasP and their insights into messaging U=U and will synthesize findings to develop resources for use by providers when discussing TasP and U=U. To do so, we will leverage the LITE cohorts to recruit 250 GBMSM diagnosed with HIV during the course of the studies—we will follow these men for two years after diagnosis, collecting home-based dried blood spot for VL on a monthly basis. In addition to self-reported data, the study will include objective indicators of adherence and care engagement and biological samples for viral load. The study will also include qualitative interviews with 50 randomly selected participants at baseline, 12-months and 24-months post-diagnosis to identify risk and resilience factors that can be used to guide future intervention development. Achieving the aims of the proposed study will provide key insights that will be critical for translating to or adapting interventions to enhance their potency and durability and improve the health of HIV-positive GBMSM.