1. Epidemiological Surveillance of HIV/AIDS Division, National Public Health Organization, Athens, Greece
2. Intensive Care Unit, Limassol General Hospital, Limassol, Cyprus
3. Euro-Mediterranean Institute for Quality and Safety in Health Services Avedis Donabedian, Athens, Greece
4. National Public Health Organization, Athens, Greece
5. Directorate of Research, Studies and Documentation, National Public Health Organization, Athens, Greece