1. School of Public Health, Southeast University; Nanjing, China
2. NHC Key Laboratory of Enteric Pathogenic Microbiology, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China
3. Clinical Research Department, Sinovac Biotech Co., LTD., Beijing, China
4. Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China