1 Department for Interventions in Health Care Facilities, Hellenic Centre for Disease Control and Prevention, Athens, Greece. Electronic address: helen-maltezou@ath.forthnet.gr.
2 Office of the President of the Board of Directors, Hellenic Centre for Disease Control and Prevention, Athens, Greece.
3 Department of Epidemiologic Surveillance and Intervention, Hellenic Centre for Disease Control and Prevention, Athens, Greece.
4 Department for Interventions in Health Care Facilities, Hellenic Centre for Disease Control and Prevention, Athens, Greece.
5 Fourth Department of Internal Medicine, Attikon University Hospital, University of Athens, Athens, Greece.
6 National Reference Laboratory for Measles and Rubella, Hellenic Pasteur Institute, Athens, Greece.
7 Department of Internal Medicine, Metropolitan Hospital, Piraeus, Greece.
8 University of Athens First Department of Pediatrics, Aghia Sophia Children Hospital, Athens, Greece.