1. Infection Prevention and Control Department, Yokohama City University Hospital, Yokohama, Japan
2. Clinical Laboratory Department, Yokohama City University Hospital, Yokohama, Japan
3. Advanced Medical Research Center, Yokohama City University, Yokohama, Japan
4. Research Center for Influenza and Respiratory Viruses, National Institute of Infectious Diseases, Musashimurayama, Japan
5. Department of Virology III, National Institute of Infectious Diseases, Musashimurayama, Japan
6. Department of Public Health, Yokohama City University School of Medicine, Yokohama, Japan