1. Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
2. Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri
3. Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut
4. Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
5. Department of Microbiology and Immunology, New York Medical College, Valhalla, New York