1. Erasmus Medical Centre, Department of Viroscience, Rotterdam, The Netherlands
2. State Institute of Public Health and Environment, Department of Infectious Disease Diagnostics, Research, and Laboratory Surveillance, Bilthoven, The Netherlands
3. Heidelberg University Hospital, Department for Infectious Diseases, Heidelberg, Germany
4. London School of Hygiene and Tropical Medicine, Department of Clinical Research, London, United Kingdom
5. Leiden University Medical Centre, Department of Medical Microbiology, Leiden, The Netherlands