1. Central Laboratory of Virology, Division of Infectious Diseases, University Hospitals of Geneva, Geneva, Switzerland
2. Swiss National Reference Center for Influenza, Central Laboratory of Virology, University Hospitals of Geneva, Geneva, Switzerland
3. Kantonales Laboratorium Basel-Stadt, Kontrollstelle für Chemie und Biosicherheit, Basel, Switzerland
4. Federal Office of Public Health, Division of Communicable Diseases, Bern, Switzerland