Dr. Koussay Dellagi is a distinguished Tunisian physician and immunologist renowned for his extensive research in infectious diseases. He earned his medical degree in 1973, specializing in clinical hematology, and later obtained a Doctorate of State in Immunology from Paris University. Throughout his illustrious career, Dr. Dellagi has held several prominent positions, including Director General of the Institut Pasteur de Tunis (1988–2007), Managing Director of the Centre de Recherche et de Veille sur les Maladies Emergentes dans l’Océan Indien in Réunion, France (2007–2015), and Scientific Advisor at the Department of International Affairs, Institut Pasteur, and subsequently at the Association Pasteur Network in Paris (2015–2023). His research primarily focuses on the epidemiology, pathophysiology, transmission, control, and prevention of infectious diseases. Dr. Dellagi has contributed to over 500 publications and has been cited more than 8,500 times, reflecting his significant impact on the field.