1 Intensive Care Department, King Saud Bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia; King Abdullah International Medical Research Center, Riyadh, Saudi Arabia. Electronic address: arabi@ngha.med.sa.
2 Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada; Department of Critical Care Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
3 Influenza and Emerging Infectious Diseases Division, Biomedical Advanced Research and Development Authority, US Department of Health and Human Services, Washington, DC, USA.
4 Outbreak Investigation Task Force, Center for Global Health, Institut Pasteur, Paris, France.
5 Paediatric Infectious Diseases, College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia; Infection Prevention and Control, King Saud Bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia; King Abdullah International Medical Research Center, Riyadh, Saudi Arabia.