1. School of Public Health, Nanjing Medical University , Nanjing, Jiangsu Province , China
2. National Health Commission (NHC) Key Laboratory of Enteric Pathogenic Microbiology, Jiangsu Provincial Center for Disease Control and Prevention , Nanjing, Jiangsu Province , China
3. CanSino Biologics, Inc , Tianjin , China
4. Department of Environmental Health, Jiangsu Provincial Center for Disease Control and Prevention , Nanjing, Jiangsu Province , China
5. Donghai County Center for Disease Control and Prevention , Donghai, Jiangsu Province , China
6. Institute of Global Public Health and Emergency Pharmacy, China Pharmaceutical University , Nanjing, Jiangsu Province , China