Awarded with the 2022 Kyoto Prize in Basic Sciences, Bryan T. Grenfell discusses population biology and the evolution of infectious diseases in his presentation during the Kyoto Prize Symposium. Grenfell's achievements have helped researchers understand infection mechanisms of viruses such as COVID-19 and have aided in proposing effective infectious disease control policies. Grenfell, a population biologist and professor of Ecology & Evolutionary Biology and Public Affairs at Princeton University, proposed phylodynamics as a methodology to predict the infectious disease dynamics of RNA viruses by considering viral evolution, thus contributing to the development of research fields that integrate immune dynamics, epidemiology, and evolutionary biology. (#38573)