PROJECT SUMMARY/ABSTRACT The burden of tuberculosis (TB) in children and adolescents is massive and current TB control strategies, even at full scale-up, are insufficient to address it.4,6-8,10 Novel strategies to expand TB control outside of the home and into the community, where children acquire an estimated 80% of new TB infections,11-12 are urgently needed. However, an incomplete understanding of where and from whom youth acquire TB, and how these drivers change throughout the early life-course, hampers the design of novel interventions. Thus, we propose the first-ever population-representative, longitudinal TB Infection Incidence Cohort of youth ages 1 to 18 years, in rural communities in Uganda. Using a combination of epidemiologic and network analytic techniques, this study will address key foundational knowledge gaps about TB transmission within 3 socio-spatial networks of youth: the household network, the non-household social network (close contacts), and the network of casual contacts encountered in community venues. In Aim 1 we will characterize the role of the household social network in TB infection throughout the early life course. In Aim 2 we will employ social network analysis to assess the relationships between child and adolescent TB infections and their community-based social network, and in Aim 3 we will use location-based networks to assess the relationships between community venues and incident TB infections in youth. Data from this proposal will directly inform novel, age-specific, community-based TB control strategies and will help optimize existing household-based strategies.