1. Department of Pediatrics (A.K.), University of Petrozavodsk, 185910 Petrozavodsk, Russia
2. Department of Virology (A.K., H.V., T.S., H.H.), University of Tampere, Medical School, 33014 Tampere, Finland
3. Department of Clinical Microbiology (A.-M.H., H.H.), Center for Laboratory Medicine, Tampere Pirkanmaa Hospital District, 33521 Tampere, Finland
4. Department of Pediatrics (P.K.), University of Oulu, 90014 Oulu, Finland
5. Department of Immunogenetics Laboratory (J.I.), University of Turku, 20014 Turku, Finland
6. Department of Clinical Microbiology (J.I.), University of Kuopio, 70211 Kuopio, Finland
7. Department of Hospital for Children and Adolescents (M.K.), University of Helsinki, 00014 Helsinki, Finland
8. Department of Pediatrics (M.K.), Tampere University Hospital, 33521 Tampere, Finland