1 Division of Infection and Immunity, University College London, London, UK; NIHR Biomedical Research Centre at UCL Hospitals, London, UK.
2 Department of Global Health, Public Health England, London, UK.
3 Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia.
4 Institute of Clinical Medicine, University of Aarhus, Aarhus 8200, Denmark; The Royal Hospital, Muscat, Oman. Electronic address: eskildp@dadlnet.dk.