PROJECT SUMMARY/ABSTRACT More than one million infants are exposed to HIV each year in high-burden sub-Saharan African countries. Yet only 60% of HIV-exposed infants are tested as recommended by two months of age. The key barriers to infant HIV testing – stigma/non-disclosure, lack of access and poor social support – may be more effectively overcome through interventions that engage women's social networks, the patterns of relationships women have with family, peers, and other community members. Social networks make salient contextual norms and enable peer learning, social support, and social engagement, all of which can affect health behaviors. There remains a scientific gap in applying social network analysis to infant HIV testing. Until this gap is addressed, there will also remain an implementation knowledge gap on how to design interventions that engage social networks to prompt infant HIV testing. The central hypothesis of this proposed grant is that social networks can influence women's decisions to test their infants for HIV. The primary objective of this K01 application is to understand how women's individual- and social network-level characteristics affect infant HIV testing to design and assess the feasibility of a social network intervention to improve infant HIV testing. The approach leverages the infrastructure from an ongoing longitudinal study (R01MH113494, PI: Tsai) with complete social network data from all adults living in 8 villages of Mbarara, Uganda and extends new primary data collection to all HIV-positive, reproductive-age women and their children born during the study period. The grant will achieve the following specific aims: 1) estimate individual- and social-network level correlates of infant testing through social network analysis exploring the roles of peer influence, social norms, social support and social engagement; 2) conduct in-depth qualitative interviews among women and integrate findings with quantitative data to understand how social network mechanisms affect infant testing and develop a conceptual framework of infant testing; 3) design and assess feasibility, acceptability, fidelity, reach and preliminary effectiveness of a social network intervention to prompt infant HIV testing. My long-term goal is to become an independent researcher with expertise in developing social network interventions to enhance HIV treatment and prevention among women and children in sub-Saharan Africa. This K01 proposal will supplement my prior training and experience with additional training and mentorship from a team of senior researchers with expertise in social networks, qualitative and mixed methods, and implementation science applied to the context of HIV. I will obtain integrated training, mentorship, and preliminary data for an R01 proposal to empirically test a novel intervention to overcome the public health problem of low infant HIV testing. The key innovation of this proposed study is that it is one of the first to a...