1. Medical Practice Evaluation Center, Massachusetts General Hospital, Boston, Massachusetts, USA
2. Biostatistics Center, Massachusetts General Hospital, Boston, Massachusetts, USA
3. Department of Global Health, Boston University School of Public Health, Boston, Massachusetts, USA
4. Travel Medicine Center, Mount Auburn Hospital, Cambridge, Massachusetts, USA
5. Harvard Medical School, Boston, Massachusetts, USA
6. Travelers’ Advice and Immunization Center, Massachusetts General Hospital, Boston, Massachusetts, USA
7. Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
8. Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
9. Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA