This chapter elaborates on several fields of electronic health data (EHD) reuse in healthcare, mainly for public interest reasons. Real-life examples of EHD reuse in epidemiology, including insights into how EHD is applied in surveillance and occupational health, are provided in the first section. The second section elaborates how EHD can be reused in supporting institutional activities and policy making: project examples carried out by eminent health institutions around the globe, such as the global World Health Organization (WHO), the continental European Centre for Disease Prevention and Control (ECDC), the American Centres for Disease Control and Prevention (CDC), and some regional institutions, such as the National Institute for Health and Care Excellence (NICE), are illustrated. The third section explores the application of EHD reuse for improving healthcare systems and for carrying out research activities. Specifically, some of the related areas covered include how EHD can be reused in learning healthcare systems, how to advance personalized medicine, how to improve healthcare quality and safety, and how to carry out various research activities. Finally, the fourth section is dedicated to the reuse of EHD for the artificial intelligence (AI) market, which has been experiencing an expansion in healthcare, addressing relevant topics such as administrative costs and associated burden reduction but also training and developing innovative AI-based tools for telemedicine to identify patients at risk for other reuses.