Marc Lipsitch is Professor of Epidemiology and Director of the Center for Communicable Disease Dynamics at the Harvard T.H. Chan School of Public Health. He is an internationally-recognized expert in methods and disease transmission modeling, and has been a leading scientific authority during the COVID-19 pandemic. Dr. Lipsitch is an author of more than 350 peer-reviewed publications on antimicrobial resistance, epidemiologic methods, mathematical modeling of infectious disease transmission, bacterial and human population genetics, immunity to Streptococcus pneumoniae, and COVID-19 epidemiology. His research informs the use of transmission-dynamic simulations to improve the design of randomized and observational studies of infectious disease interventions, and bioethics related to infectious diseases and clinical trials in emergencies.