1. Hellenic Center for Disease Control and Prevention, Athens, Greece
2. University of Athens Medical School, Athens Greece
3. Hellenic Pasteur Institute, Athens, Greece
4. Microbiology Department, University of Athens Medical School, Athens, Greece
5. National Health Operations Center, Athens, Greece
6. Metropolitan Hospital Athens Greece
7. First Department of Respiratory Medicine, University of Athens Medical School, Athens, Greece
8. Intensive Care Medicine first Department of Respiratory Medicine, University of Athens Medical School, Athens Greece