1. Department of Infectious Disease Epidemiology, Statens Serum Institut, Copenhagen, Denmark
2. European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
3. Department of Microbiological Diagnostics and Virology, Statens Serum Institut, Copenhagen, Denmark
4. Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
5. Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
6. Department of Infectious Disease Surveillance and Control, National Institute for Health and Welfare, Helsinki, Finland
7. Department of Preparedness, Swedish Institute for Communicable Disease Control, Stockholm, Sweden
8. Department of Epidemiology and Biostatistics, Swedish Institute for Communicable Disease Control, Stockholm, Sweden
9. The Danish Veterinary and Food Administration, Copenhagen, Denmark
10. Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark