1. Expand Program on Immunization, Chongqing Center for Disease Control and Prevention, Chongqing, China
2. Expand Program on Immunization, Yuzhong District Center for Disease Control and Prevention, Chongqing, China
3. Expand Program on Immunization, Yubei District Center for Disease Control and Prevention, Chongqing, China
4. Expand Program on Immunization, Jiulongpo District Center for Disease Control and Prevention, Chongqing, China