1. Department for Interventions in Healthcare Facilities, Hellenic Center for Disease Control and Prevention, Athens, Greece.
2. National Influenza Reference Laboratory for Southern Greece, Hellenic Pasteur Institute, Athens, Greece.
3. Office of Scientific Collaborators, Hellenic Center for Disease Control and Prevention, Athens, Greece.
4. National Influenza Reference Laboratory for Northern Greece, Microbiology Department, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece.