Affiliation: | 1. Virology Unit, National Institute for Health and Welfare (THL), , Helsinki, Finland;2. Department of Pediatrics, Turku University Hospital and University of Turku, , Turku, Finland;3. Immunogenetics Laboratory, University of Turku, , Turku, Finland;4. Department of Clinical Microbiology, University of Eastern Finland, , Kuopio, Finland |