1 Division of Virology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan; The Research Center for Global Viral Diseases, National Center for Global Health and Medicine Research Institute, Tokyo, Japan.
2 Division of Virology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
3 Division of Infectious Diseases, Advanced Clinical Research Center, University of Tokyo, Tokyo 108-8639, Japan; Department of Infectious Diseases and Applied Immunology, Hospital of The Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
4 Division of Infectious Diseases, Advanced Clinical Research Center, University of Tokyo, Tokyo 108-8639, Japan; Division of Virology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
5 Department of Infectious Diseases and Applied Immunology, Hospital of The Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
6 Clinic of Nihon Sumo Kyokai, Tokyo, Japan.
7 Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
8 Department of Microbiology and Immunology, School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
9 Division of Virology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan; Pandemic Preparedness, Infection and Advanced Research Center, University of Tokyo, Tokyo 108-8639, Japan; The Research Center for Global Viral Diseases, National Center for Global Health and Medicine Research Institute, Tokyo, Japan; Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA. Electronic address: yoshihiro.kawaoka@wisc.edu.