1. Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, Hunan, China
2. Department of Obstetrics and Gynecology, Faculty of Medicine, OMNI Research Group, University of Ottawa, Ottawa, Ontario, Canada
3. Ottawa Hospital Research Institute, Clinical Epidemiology Program, Ottawa, Ontario, Canada
4. School of Epidemiology, Public Health, and Preventive Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
5. Department of Mathematics, Mzuzu University, Mzuzu, Malawi
6. Immunization Programme Department, Hunan Provincial Center for Disease Control and Prevention, Changsha, Hunan, China