[1] King Saud bin Abdulaziz Univ Hlth Sci, King Abdullah Int Med Res Ctr, Dept Intens Care, POB 22490, Riyadh 11426, Saudi Arabia
[2] Univ Oxford, Ctr Trop Med CCVTM, Churchill Hosp Old Rd, Oxford OX3 7LE, England
[3] King Saud bin Abdulaziz Univ Hlth Sci, King Abdullah Int Med Res Ctr, Infect Control Dept, Riyadh, Saudi Arabia
[4] King Saud bin Abdulaziz Univ Hlth Sci, King Abdullah Int Med Res Ctr, Emergency & Crit Care Med, Riyadh, Saudi Arabia
[5] AlFaisal Univ, Riyadh, Saudi Arabia
[6] King Saud bin Abdulaziz Univ Hlth Sci, King Abdulaziz Med City, Crit Care & Pulm Med, Jeddah, Saudi Arabia
[7] WHO, Pandem & Epidem Dis Dept, Geneva, Switzerland
[8] Univ Toronto, Dept Med, Toronto, ON, Canada
[9] Univ Toronto, Inst Hlth Policy Management & Evaluat, Toronto, ON, Canada
[10] Sunnybrook Hlth Sci Ctr, Dept Med, Toronto, ON, Canada
[11] Sunnybrook Hlth Sci Ctr, Interdept Div Crit Care Med, Toronto, ON, Canada
[12] Int Severe Acute Resp & Emerging Infect Cosortium, Old Rd Campus, Headington OX3 7FZ, England