Anna Wald, M.D., M.P.H., Professor in the Department of Medicine, Epidemiology, and Laboratory Medicine, and Head of the Division of Allergy and Infectious Diseases, University of Washington, Seattle, is an infectious diseases specialist and epidemiologist. The focus of her studies has been the epidemiology and natural history of viral infections, with emphasis on the course of viral shedding throughout the disease and its relationship to transmission. She is also an investigator in clinical trials of candidate vaccines and antivirals.