1. Department of Hygiene, Epidemiology and Medical Statistics, Medical School, National & Kapodistrian University of Athens, 11527 Athens, Greece
2. 4th Department of Internal Medicine, Attikon University General Hospital, Medical School, National & Kapodistrian University of Athens, 12461 Athens, Greece
3. Department of Internal Medicine, University General Hospital of Patras, Department of Medicine, University of Patras, 26504 Rio, Greece
4. 1st Department of Critical Care & Pulmonary Service, Evangelismos General Hospital, Medical School, National & Kapodistrian University of Athens, 10676 Athens, Greece
5. COVID-19 Unit, Evangelismos General Hospital, 10676 Athens, Greece
6. 3rd Department of Internal Medicine, Athens Hospital for Diseases of the Chest “Sotiria”, Medical School, National & Kapodistrian University of Athens, 11527 Athens, Greece
7. Department of Internal Medicine, University General Hospital of Ioannina, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45500 Ioannina, Greece
8. Department of Internal Medicine, University General Hospital of Alexandroupolis, Department of Medicine, Democritus University of Thrace, 68100 Alexandroupolis, Greece
9. Medical Affairs, Gilead Sciences Hellas and Cyprus, 17564 Paleo Faliro, Greece