PROJECT SUMMARY In this renewal application, Benjamin Chi, MD, MSc seeks dedicated support for research and mentorship of patient-oriented researchers at the intersection of HIV, maternal and child health, and global health. This proposal builds upon an impressive K24 track record to date: individual mentorship of 26 early-stage investigators (including 10 NIH K awardees), work to enhance mentorship capacity in international academic institutions, and high levels of research productivity. He seeks to build upon this successful mentoring program, in ways that broaden impact and scope and are attuned to his current career stage. Candidate: Dr. Chi is a recognized thought leader in the prevention of mother-to-child HIV transmission (PMTCT). He has led clinical trials, observational cohorts, modeling studies, household surveys, and—with support in the first K24 cycle— implementation research. Over the past five years, he has taken on leadership roles at his home institution, but mentorship remains the cornerstone of his academic career. This award provides protected effort for such activities, allowing him to refine his approach at a critical career juncture. Mentoring Plan/Environment: Dr. Chi has an established track record in research training, including leadership of multiple NIH-funded initiatives. His approach to mentorship has been highly productive but time-intensive. In this renewal, he introduces new activities that foster group and peer mentoring, emphasize joint learning, and provide support for new mentors. He will leverage UNC’s extensive resources to accomplish this goal, including NIH-funded centers and training programs, networks and collaborations, and global health institutes and departments. This includes professional development designed to improve his mentoring skills and support mentees on their path to research independence. Research Plan: This proposal has a sharpened topical focus. HIV prevention for pregnant and postpartum women is an emerging global priority in the field of maternal health and PMTCT; however, biological, clinical, cultural, and social factors that are unique to these periods are often overlooked. Through mentored research, this program seeks to develop this expertise in early-stage investigators. Three projects are described that will collectively provide valuable insights about HIV risk and the use of HIV prevention interventions (in this case, pre-exposure prophylaxis or PrEP) among pregnant and postpartum women. Scientifically, these aims follow a rational and clear progression: (1) characterizing HIV risk among pregnant and postpartum women, (2) describing the alignment of perceived HIV risk and PrEP use during these periods, and (3) designing and assessing a new intervention to improve this alignment. Each of these studies build upon funded NIH research led by Dr. Chi and his collaborators. They represent a body of work that will remain relevant as the HIV prevention landscape continues to evolve. Imp...