1. Department of Virology, Medical School, University of Tampere, Tampere, Finland;
2. School of Public Health, University of Tampere, Tampere, Finland;
3. Department of Clinical Microbiology, University of Eastern Finland, Kuopio, Finland;
4. Immunogenetics Laboratory, University of Turku, Turku, Finland;
5. Department of Pediatrics, University of Oulu, Oulu, Finland;
6. Department of Pediatrics, University of Turku, Turku, Finland;
7. Department of Pediatrics, Tampere University Hospital, Tampere, Finland;
8. Hospital for Children and Adolescents and Folkhälsan Research Center, University of Helsinki, Helsinki, Finland;
9. Department of Clinical Microbiology, Centre of Laboratory Medicine, Tampere University Hospital, Tampere, Finland.