Nanjing Medical University, Academy of Military Medical Sciences - Institute of Biotechnology, CanSino Biologics Inc., Jiangsu Provincial Center for Disease Control and Prevention - NHC Key Laboratory of Enteric Pathogenic Microbiology, Chinese Center for Disease Control and Prevention (China CDC) - National Immunization Program, Jiangsu Provincial Center for Disease Control and Prevention - NHC Key Laboratory of Enteric Pathogenic Microbiology, Academy of Military Medical Sciences - Institute of Biotechnology, Chinese Center for Disease Control and Prevention (China CDC), Academy of Military Medical Sciences - Institute of Biotechnology, Jiangsu Provincial Center for Disease Control and Prevention - NHC Key Laboratory of Enteric Pathogenic Microbiology, Government of the People's Republic of China - Center of Disease Control and Prevention, Chongqing Center for Disease Control and Prevention, Nanjing Medical University - School of Public Health, Anhui Provincial Center for Disease Control and Prevention, Chongqing Center for Disease Control and Prevention, Shandong Provincial Center for Disease Control and Prevention, Yunan Provincial Center for Disease Control and Prevention, Hunan Provincial Center for Disease Control and Prevention, Anhui Provincial Center for Disease Control and Prevention, Hunan Provincial Center for Disease Control and Prevention, Yunan Provincial Center for Disease Control and Prevention, CanSino Biologics Inc., Nanjing Medical University - Department of Epidemiology and Biostatistics, Academy of Military Medical Sciences - Institute of Biotechnology and Jiangsu Provincial Center for Disease Control and Prevention - NHC Key Laboratory of Enteric Pathogenic Microbiology