1. Department of Emergency Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
2. Center for Disease Dynamics, Economics & Policy, Washington DC, USA
3. Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
4. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
5. Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA