1. Center for Infectious Diseases Epidemiologic Research, Mailman School of Public Health, Columbia University, New York, New York
2. Department of Epidemiology and Biostatistics, University of California, San Francisco, California
3. Department of Epidemiology, Center for Social Epidemiology and Population Health, University of Michigan, School of Public Health, Ann Arbor, Michigan
4. Department of Pathology and Laboratory Medicine, University of California, Davis, California