1. School of Population Medicine and Public Health, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
2. Beijing Center for Disease Prevention and Control, Beijing Research Center for Preventive Medicine, Beijing, China
3. School of Public Health, Capital Medical University, Beijing, China
4. Center for Applied Statistics and School of Statistics, Renmin University of China, Beijing, China
5. Department of programmed immunization, Haidian District Center for Diseases Control and Prevention, Beijing, China
6. Department of programmed immunization, Chaoyang District Center for Diseases Control and Prevention, Beijing, China
7. Department of programmed immunization, Changping District Center for Diseases Control and Prevention, Beijing, China
8. Department of programmed immunization, Huairou District Center for Diseases Control and Prevention, Beijing, China