1. Department of Virology, University of Tampere, Tampere, Finland
2. Department of Clinical Microbiology, Center for Laboratory Medicine, Tampere University Hospital, Tampere, Finland
3. Department of Pediatrics, University of Petrozavodsk, Petrozavodsk, Russia
4. National Health Institute, Oulu, Finland
5. Department of Pediatrics, Tampere University Hospital, Tampere, Finland
6. Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland