Marc Lipsitch is Professor of Epidemiology and Director of the Center for Communicable Disease Dynamics (CCDD) at the Harvard School of Public Health. He studies the population-level impact of medical and public health interventions to treat and control infectious diseases. His studies combine classical epidemiology, pathogen population genomics, mathematical modeling and laboratory experiments. Working closely with local, state, national and international health authorities, his group contributed to the modeling and analysis of the 2003 SARS epidemic and 2009 influenza pandemic, and to the analysis of the 2011 E. coli O104:H4 outbreak in Europe. Current research interests include flu seasonality and forecasting, antimicrobial resistance, and pandemic preparedness and response. Follow the CCDC Twitter feed @CCDD_HSPH.