Holly C. Hagan is an American infectious disease epidemiologist and nurse. She is a full professor in the College of Global Public Health at New York University and director of the Center for Drug Use and HIV/HCV Research.

Hagan earned her Bachelor of Arts degree from Evergreen State College, her Master's degree from the University of Massachusetts, Amherst, and PhD from the University of Washington.^[1]

Upon completing her PhD, Hagan accepted a faculty position at New York University (NYU) College of Global Public Health. As a senior research scientist, Hagan and Sherry Deren were appointed co-editors of the Substance Use & Misuse special issue on "The New York HIV-Drug Use Epidemic: Lessons Learned and Unresolved Issues."^[2] Throughout her tenure at NYU, she studied epidemiology, prevention, natural history and treatment of hepatitis C virus infection in people who use drugs as co-director of the Center for Drug Use and HIV/HCV Research.^[1] In 2018, Hagan was appointed chair of the Executive Steering Committee for the National Institutes of Health and the Centers for Disease Control and Prevention’s Rural Opioid Initiative.^[3] She was also named to the National Academy of Medicine's Committee on the Examination of the Integration of Opioid and Infectious Disease Prevention Efforts in Select Programs.^[4]

During the COVID-19 pandemic in North America, Hagan and Vincent Guilamo-Ramos were the principal investigators of a National Institutes of Health study aimed at providing personalized health care to those in public housing. The funds were used to implement and evaluate a household-centered service-delivery that sent nurses and community health workers door-to-door in public housing to prevent the spread of coronavirus.^[5]