Dr Kassiani Mellou is an epidemiologist working at the Hellenic National Public Health Organization (HNPHO) for the last 20 years. She has been the Head of the Directorate of Epidemiological Surveillance and Response for Infectious Diseases of HPHO since February 2022. The main focus of her work is surveillance, outbreak investigation, and applied epidemiology and she has participated in the investigation of more than 70 large national and international outbreaks (head of the investigation team in most of them). She has participated to more than 60 peer-reviewed international journal articles and has contributed to chapters in five books on epidemiology and surveillance.