1. Charité - Universitätsmedizin Berlin, Germany
2. Health Protection Scotland, Glasgow, United Kingdom
3. Swedish National Institute of Public Health, Solna, Sweden
4. Center for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
5. Institut de Veille Sanitaire, Saint-Maurice Cedex, France
6. National Institute for Health and Welfare, Helsinki, Finland
7. European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
8. University of Leeds, Leeds, United Kingdom
9. Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
10. Leiden University Medical Center, Leiden, the Netherlands