1. Department of Infectious Diseases, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
2. Department of Family Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
3. Long-term care facility Danice Vogrinec Maribor, Maribor, Slovenia
4. Long-term care facility for the elderly Trebnje, Trebnje, Slovenia
5. Department of Infectious Diseases, University Medical Centre Ljubljana, Ljubljana, Slovenia