1. Primary Care Setting, Primary Health Centre of Kissamos, 73400 Chania, Crete, Greece
2. Department of Social Medicine, University of Crete, 71500 Heraklion, Crete, Greece
3. Clinic of Social and Family Medicine, Faculty of Medicine, University of Crete, 71500 Heraklion, Crete, Greece
4. Laboratory of Clinical Virology, School of Medicine, University of Crete, 71500 Heraklion, Crete, Greece