USC Faculty and Staff

GRIT Lab Director

Dr. Heather Wipfli, PhD, Director of Undergraduate Health Promotion and Global Health Degree Programs and Professor of Population and Public Health Sciences and International Relations at the University of Southern California Keck School of Medicine, USC Norris Comprehensive Cancer Center, and Dornsife College of Arts, Letters and Sciences, is a global health scientist with over two decades of research and program experience throughout the world. Dr. Wipfli is the founding director of the USC Global Research, Implementation, and Training (GRIT) Lab, a research collaborative focused on addressing persistent ‘wicked problems’ through  trans-disciplinary cooperation and implementation science. Dr. Wipfli was also the founding Associate Director of the USC Institute for Global Health and, prior to joining USC, she directed projects at the Institute for Global Tobacco Control at the Johns Hopkins Bloomberg School of Public Health and was a technical officer within the Tobacco Free Initiative at the World Health Organization headquarters in Geneva, Switzerland.

GRIT Lab Manager

Kyra Guy, MPH is a graduate from USCs Master in Public Health Program. Her passion for public health has led her to work in infection prevention, peer health education, and data collection and analysis for the GRIT lab. Following her masters program, Kyra has continued to assist GRIT lab in developing evidence-based interventions for behavioral and environmental changes improving global health outcomes and is now starting her PhD in Health Behavior Research at the Keck School of Medicine at USC.

Affiliated USC Faculty

Mellissa Withers, PhD, MHS is Associate Professor at the Keck School of Medicine in the Department of Population and Public Health Sciences. She is the co-director of the USC Online MPH Program and  Director of the Global Health Program of the Association of Pacific Rim Universities, a non-profit network of over 60 universities in the Asia-Pacific. Her research interests are global health, mental health, sexual and reproductive health and gender-based violence. Dr Withers’ work spans the globe, with projects in Latin America, Africa and Asia. She received a PhD from the UCLA Fielding School of Public Health with a minor in anthropology. She also earned a Master’s in International Health from the Johns Hopkins Bloomberg School of Public Health and a BA in international development from UC Berkeley. She teaches courses on global health leadership, global health ethics, and research methods. Dr Withers is the co-editor of two books, has published more than 60 scientific articles and serves on the editorial boards of numerous international global health journals.

Sigita Cahoon, MD, MPH is an Assistant Professor of Clinical Obstetrics & Gynecology at USC. She received her BA in Biology at Boston University and her MD from the University of Miami. She completed her residency in Obstetrics and Gynecology at LAC+USC Medical Center, followed by a fellowship in Global Women’s Health at LAC+USC, where she partnered with GRIT to increase cervical cancer screening capacity in Mpigi, Uganda. She is Board Certified in her specialty and is a Fellow of the American Congress of Obstetricians and Gynecologists.

Dr. Lily Chattopadhyay, MD is a Clinical Assistant Professor of Pediatrics at Children’s Hospital Los Angeles (CHLA).  Her primary interests within medicine are global health, environmental health, and sustainability in health care. She has extensive global health experience in Sierra Leone, Uganda, Bolivia, and Malawi.  During her residency training at CHLA, she was the inaugural resident in the IMPACT Global Health track and completed a 3-year, longitudinal research study facilitated by GRIT in Mpigi, Uganda aimed at understanding environmental risk factors contributing to childhood diarrheal disease.  After completing her residency, she worked in Sierra Leone with Partners in Health running their pediatric ward and malnutrition services in Kono as the Ebola epidemic was ending.  She had previously conducted research in Freetown, Sierra Leone examining adherence to HIV/AIDs therapies.  More recently, she has worked with Operation Smile as the lead pediatrician on a mission to Bolivia.  She then traveled to Malawi to help lead a malnutrition training for clinical health workers alongside members of the Ministry of Health on behalf of Operation Smile.