1. Division of Hematology-Oncology and Stem Cell Transplantation; Children's Hospital; University of Helsinki; Helsinki Finland
2. Department of Pediatrics; Porvoo Hospital; Porvoo Finland
3. Department of Pediatrics; Turku University Hospital; Turku Finland
4. Department of Virology; University of Helsinki; Helsinki Finland
5. Division of Microbiology and Genetics; Department of Clinical Virology; Turku University Hospital; Turku Finland
6. Department of Virology; University of Turku; Turku Finland
7. Department of Virology and Immunology; Helsinki University Hospital Laboratory Services (HUSLAB); Helsinki Finland
8. Department of Clinical Microbiology; Karolinska University Hospital; Stockholm Sweden