1 Influenza Centre, University of Bergen, N-5021 Bergen, Norway; Department of Medicine, Haukeland University Hospital, Bergen, Norway. Electronic address: Kristin.mohn@uib.no.
2 Influenza Centre, University of Bergen, N-5021 Bergen, Norway; Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway.
3 Influenza Centre, University of Bergen, N-5021 Bergen, Norway; Department of Safety, Chemistry and Biomedical Laboratory Sciences, Western Norway University of Applied Sciences, Bergen, Norway.
4 Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0315 Oslo, Norway; Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway.
5 Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0315 Oslo, Norway; Department of Infectious Diseases, Oslo University Hospital, 0424 Oslo, Norway.
6 Influenza Centre, University of Bergen, N-5021 Bergen, Norway; Department of Microbiology, Haukeland University Hospital, Bergen, Norway.