1. Laboratory of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa, Greece
2. Faculty of Midwifery, School of Health Sciences, University of Western Macedonia, Kozani, Greece
3. National Influenza Reference Laboratory for Northern Greece, Microbiology Department, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
4. Institute of Biosciences, University Research Center of loannina, Ioannina, Greece
5. Center for Evidence Synthesis in Health, Department of Health Services, Policy and Practice, School of Public Health, Brown University, Providence, United States
6. Department of Hygiene and Epidemiology, University of Ioannina Faculty of Medicine, Ioannina, Greece
7. Department of Public Health Policy, School of Public Health, University of West Attica, Athens, Greece
8. Department of Microbiology, University Hospital of Larissa, University of Thessaly, Larissa, Greece
9. Third Department of Paediatrics, National and Kapodistrian University of Athens, School of Medicine, Attikon University Hospital, Athens, Greece
10. Department of Immunology and Histocompatibility, Faculty of Medicine, University of Thessaly, Larissa, Greece
11. Fourth Department of Internal Medicine, National and Kapodistrian University of Athens, School of Medicine, Attikon University Hospital, Athens, Greece