1. Laboratory of Clinical Virology, School of Medicine, University of Crete, 71003 Heraklion, Greece
2. Paediatric Intensive Care Unit (PICU), ‘Penteli’ Children's Hospital, 152 36 Athens, Greece
3. Paediatric Intensive Care Unit (PICU), ‘Aglaia Kyriakou’ Children's Hospital, 115 27 Athens, Greece