Affiliation: | a Department of Otorhinolaryngology, Head & Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland b Hospital for Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland c Department of Pediatrics, Jorvi Hospital, Helsinki University Central Hospital, Helsinki, Finland d Department of Viral Diseases and Immunology, National Public Health Institute, Helsinki, Finland e Department of Virology, Haartman Institute, Helsinki University, Helsinki, Finland. |