1. School of Public Health, Southeast University, Nanjing, Jiangsu Province, China
2. NHC Key Laboratory of Enteric Pathogenic Microbiology (Jiangsu Provincial Center for Disease Control and Prevention), Nanjing, Jiangsu Province, China
3. Clinical operation center, CanSino Biologics Inc, Tianjin, P. R. China
4. Funing Country Center for Disease Control and Prevention, Yancheng, Jiangsu Province, China
5. Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu Province, China
6. Institute of Global Public Health and Emergency Pharmacy, China Pharmaceutical University, Nanjing, China