1 Division of Infection and Immunity, Center for Clinical Microbiology, University College London, London, UK; NIHR Biomedical Research Centre, UCL Hospitals NHS Foundation Trust, London, UK.
2 Infectious Diseases Division, Department of Medicine and Department of Research, Prince Mohamed Bin Abdulaziz Hospital, Riyadh, Saudi Arabia; Ministry of Health and College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
3 Division of Respiratory Medicine and Stanley Ho Center for Emerging Infectious Diseases, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, Special Administrative Region, China.
4 Department of Microbiology and Immunology and Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA. Electronic address: stanley-perlman@uiowa.edu.