1 Institute of Clinical Medicine, University of Aarhus, Denmark; The Royal Hospital, Muscat, Oman. Electronic address: firstname.lastname@example.org.
2 National Institute for Communicable Diseases, Johannesburg, South Africa. Electronic address: email@example.com.
3 Epidemiology and Biostatistics, School of Medicine, University of California San Francisco, USA; Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Electronic address: firstname.lastname@example.org.
4 Division of Infection and Immunity, University College London, London, UK; National Institute of health Research, Biomedical Research Centre at UCL Hospitals, London, UK. Electronic address: email@example.com.