1.Xiangya Hospital, Central South University, Changsha 410008, China;2.National Clinical Research Center for Geriatric Disorders[Xiangya Hospital], Changsha 410008, China;3.Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China;4.Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China;5.The People's Hospital of Liaoning Province, Shenyang 110016, China;6.The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China;7.The Third People's Hospital of Shenzhen, Shenzhen 518112, China;8.National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China;9.Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China;10.Division of Infectious Diseases, Chinese Center for Disease Control and Prevention, Beijing 102206, China;11.National Influenza Centre, Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China;12.China-Japan Friendship Hospital, Beijing 100029, China;13.Wuhan Jinyintan Hospital, Wuhan 430013, China;14.The First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310003, China;15.Shanghai Pulmonary Hospital, Tongji University, Shanghai 200433, China;16.Children's Hospital of Fudan University, Shanghai 201102, China;17.Shanghai Daotian Evidence-based Technology Co., Ltd, Tianjin 300000, China;18.West China Hospital, Sichuan University, Chengdu 610041, China;19.Peking University First Hospital, Beijing 100034, China;20.Chinese PLA Gene-ral Hospital, Beijing 100039, China