Sean T. O’Leary, MD, MPH, is a professor of pediatrics and infectious diseases at the University of Colorado Denver Anschutz Medical Campus and Children’s Hospital Colorado. He is also an investigator at Adult and Child Center for Outcomes Research and Delivery Science (ACCORDS) and director of the Colorado Children’s Outcomes Network (COCONet), a pediatric practice-based research network. His research focuses on prevention of vaccine-preventable diseases through understanding clinical, attitudinal, and infrastructural barriers to vaccination, and developing and testing interventions to address those barriers. O’Leary is a member of the American Academy of Pediatrics (AAP) Council on School Health, serves as chair of the Committee on Infectious Diseases, and serves as AAP liaison to ACIP, including representing AAP on the ACIP COVID-19 and RSV Work Groups. He also serves as co-chair of the Policy Committee for Immunize Colorado and has been a speaker at the NFID Clinical Vaccinology Course since 2017.