1. Arturo Casadevall, MD, PhD, is a Professor, Department of Medicine, Division of Infectious Diseases, and a Professor and the Leo and Julia Forchheimer Chair in Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York. Michael J. Imperiale, PhD, is a Professor in the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan.