1. Division of Infectious Diseases, Massachusetts General Hospital , Boston, Massachusetts , USA
2. Department of Medicine, Harvard Medical School , Boston, Massachusetts , USA
3. Department of Medicine, Massachusetts General Hospital , Boston, Massachusetts , USA
4. Faculty of Medicine, American University of Beirut Medical Center , Beirut , Lebanon
5. Faculty of Medicine, University of Balamand , Beirut , Lebanon
6. B·R·A·H·M·S GmbH, part of Thermo Fisher Scientific , Hennigsdorf , Germany