Impact of the 2018 Changchun Changsheng Vaccine Incident on Childhood Vaccination in China: Evidence From Vaccination Records and a National Survey

Background: As an emergent public health event in China, the Changchun Changsheng vaccine incident occurred in 2018 following reports of DTaP vaccines with compromised efficacy.<br><br>Methods: A cross-sectional survey was conducted in ten provinces in 2019. Vaccination records were collected from 5 294 children aged 6-59 months at the survey time, with information on 75 579 vaccine doses for seven National Immunization Program (NIP) vaccines and two non-NIP vaccines received from 2014 to 2019. Chi-square test, interrupted time series, and logistic regression were used to evaluate the impacts of vaccine incident on vaccination delay, measured as the proportion of delayed doses out of total doses in schedule.<br><br>Findings: Significant increases in the proportion of doses delayed ≤3 months (19·12% to 22·51%, p&lt;0·01) and &gt;3 months (7·17% to 11·82%, p&lt;0·01) were observed for DTaP vaccine after the incident. By scaling nationally, there would be an estimated extra 2·1 million doses delayed ≤3 months and 2·8 million doses delayed &gt;3 months in the year following this incident. More guardians chose the expensive private-market substitutes that covered DTaP elements over government-funded DTaP vaccines involved in the incident. Controlling for socio-demographic factors, doses scheduled after the incident had higher odds of delays for DTaP vaccine (OR: 3·49, 95% CI: 3·08-3·96) and other NIP vaccines (OR: 2·76, 95% CI: 2·55-2·99), but no significant difference for non-NIP vaccines.<br><br>Interpretation: The observed delays for the incident-involved DTaP vaccine reflect the negative effects of vaccine incident on vaccination behaviors under the NIP. However, its effects seem minimal for non-NIP vaccines.<br><br>Trial Registration Details: This study was registered at clinicaltrials.gov (NCT04038333).<br> <br>Funding Information: No funding sources.<br><br>Declaration of Interests: All authors declare no competing interests.<br> <br>Ethics Approval Statement: This study was approved by the Peking University Institutional Review Board (IRB00001052-19076). Written informed consent was obtained from children’s guardians.<br>