Gregory D. Zimet, PhD, is professor of pediatrics and a clinical psychologist in the Section of Adolescent Medicine, Department of Pediatrics at Indiana University School of Medicine, Indianapolis, USA. He is co-director of the Indiana University-Purdue University Center for HPV Research and a member of the Indiana University Simon Comprehensive Cancer Center. Dr. Zimet received his doctorate in clinical psychology from Duke University, Durham, North Carolina. He completed a predoctoral internship in clinical psychology and a postdoctoral fellowship in adolescent clinical psychology at Case Western Reserve University School of Medicine in Cleveland. Much of Dr. Zimet’s research has involved the study of vaccine acceptance and refusal, with a primary focus on behavioral and social determinants of human papillomavirus vaccination. His studies have focused on adolescents and young adults, parents of adolescents, and health care providers, and include evaluations of vaccine communication strategies.