Institution: | 1. Department of Virology, Norwegian Institute of Public Health, Oslo, Norway;2. Department of Medical Microbiology, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway;3. Department of Medical Microbiology St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway;4. Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway |