1. a Department of Emergency Medicine , Warren Alpert Medical School of Brown University, Rhode Island Hospital , Providence , RI , USA
2. b Department of Community Health , Warren Alpert Medical School of Brown University , Providence , RI , USA
3. c Department of Epidemiology , Harvard School of Public Health , Boston , MA , USA
4. d Department of Medicine, Division of Infectious Diseases , Warren Alpert Medical School of Brown University , Providence , RI , USA
5. e Department of Biostatistics , Harvard School of Public Health , Boston , MA , USA