1. Epidemic Intelligence Service, Centers for Disease Control and Prevention , Atlanta, Georgia , USA
2. Communicable and Environmental Diseases and Emergency Preparedness Division, Tennessee Department of Health , Nashville, Tennessee , USA
3. Department of Biostatistics, Vanderbilt University School of Medicine , Nashville, Tennessee , USA
4. Department of Health Policy, Vanderbilt University Medical Center , Nashville, Tennessee , USA
5. Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center , Nashville, Tennessee , USA