The relationship between HIV exposure, contact networks, and TB in children under 5 years old - PROJECT SUMMARY / ABSTRACT More than 200,000 children die each year from TB, of whom 80% are <5 years old. HIV is a leading risk factor for TB disease in both children and adults. Despite longstanding reliance upon household contact tracing to identify children with TB, recent estimates suggest that only 10-30% of children with TB are infected within their households. Meanwhile a massive pediatric TB detection gap exists, with only 40% of children <5 years old with TB disease being diagnosed and reported. Understanding where and from whom children are infected with TB is vital to closing this gap. Because adult HIV likely affects both the composition and TB burden of children’s “contact networks”, it is critical to examine the role adult HIV plays in driving TB transmission to children. It is likewise essential to examine the interaction between adult HIV and child TB in a growing group that is highly susceptible to early childhood infections: children who are HIV exposed but uninfected. The proposed project aims to evaluate the interplay between caregiver/adult HIV infection, complex and dynamic child contact networks, and child TB exposure and incidence. To do so, in Aim 1 I will leverage the Pediatric TB Contact Studies Consortium individual patient data meta-analysis database to measure the association between adult index case HIV status and prevalent and incident child TB infection and disease. In Aim 2, I will use egocentric social network analysis to track the evolution of social networks among children who are HIV exposed but uninfected and who are enrolled in a prospective birth cohort study in the Western Cape province, South Africa. Through this aim, I will explore how changes in social network diversity relate to cumulative TB incidence in the first 2 years of life in this high-risk population. In Aim 3, I will employ ethnographic methods to generate detailed assessments of “household fluidity”—a qualitative measure of household composition, relational ties, and residential structure—to identify opportunities for TB exposure that have been historically overlooked in traditional household contact tracing. These activities will take place within the rich HIV and TB academic environments at Boston Medical Center/Boston University and Stellenbosch University (South Africa), and in the high HIV/TB-burden setting of Worcester, South Africa. Melded with a training plan that balances coursework, workshops, and hands-on experience, these research aims will provide an ideal framework for me to develop skills in survival analysis using clustered data, social network analysis, and ethnography. The proposed projects and training will enable me to become an independent investigator conducting prospective, longitudinal, social-epidemiological studies at the intersection of pediatric TB and HIV. An experienced mentorship team led by Dr. Karen Jacobson (Boston Medical Center/Boston University) and Dr. Graeme Hoddinott (Stellenbosch University) will guide this training and support this research. My goal through the proposed and future studies is to inform strategies to prevent and detect TB in children, who have most to lose from and are most susceptible to this perennial pandemic.
