1. Public Health & Vaccines Laboratory, Faculty of Nursing, School of Health Sciences, University of Thessaly, 41110 Larissa, Greece
2. National Health System of Greece, Primary Health Center of Vari, 16672 Athens, Greece
3. National Health System of Greece, Primary Health Center, 23062 Areopolis, Greece
4. Respiratory Disorders Lab, Faculty of Nursing, University of Thessaly, 41110 Larissa, Greece
5. Private Primary Health Sector, Queen Sophia Avenue 123, 11521 Athens, Greece
6. Microbiology Department, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece
7. Laboratory of Clinical Chemistry-Biochemistry, University Hospital of Heraklion, 71003 Crete, Greece
8. Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece
9. Department of Social Medicine, Faculty of Medicine, University of Crete, 71003 Heraklion, Greece
10. Department of Hygiene and Epidemiology, Medical Faculty, School of Health Science, University of Thessaly, 42200 Larissa, Greece
11. Department of Respiratory Medicine, Faculty of Medicine, School of Health Sciences, University of Thessaly, BIOPOLIS, 41110 Larissa, Greece