Dr. Marc Lipsitch is a Professor of Epidemiology at the Harvard School of Public Health with a primary appointment in the Department of Epidemiology and a joint appointment in the Department of Immunology and Infectious Diseases. He also directs the Center for Communicable Disease Dynamics, a center of excellence funded by the MIDAS program of NIH/NIGMS, and the Associate Director of the Interdisciplinary Concentration in Infectious Disease Epidemiology. His research concerns the effect of naturally acquired host immunity, vaccine-induced immunity and other public health interventions (e.g. antimicrobial use) on the population biology of pathogens and the consequences of changing pathogen populations for human health. Some of this work is motivated mainly by practical questions in public health (such as vaccine design and intervention targeting), and some is motivated by classical questions in population biology, such as how to explain patterns of coexistence of pathogen strains in space and time. Dr. Lipsitch received his BA in philosophy from Yale University, completed his doctoral work in zoology at Oxford University as a Rhodes Scholar and did postdoctoral work at Emory University and at the CDC from 1995-1999. He joined the faculty of Harvard School of Public Health in 1999.