1 Division of Infectious Diseases, Department of Medicine, Hamad Medical Corporation, Doha, Qatar; Communicable Diseases Centre, Hamad Medical Corporation, Doha, Qatar.
2 Infectious Diseases Section, Department of Medical Specialties King Fahad Medical City, Riyadh, Saudi Arabia; College of Medicine, Alfaisal University, Riyadh, Saudi Arabia; Division of Infectious Diseases, Mayo Clinic College of Medicine and Science, Rochester, MN, USA; Division of Epidemiology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA. Electronic address: [email protected].