Based on social ecosystem theory (SET), this study investigated parents’ willingness to vaccinate their children with non-expanded program on immunization (non-EPI) vaccines and its influencing factors.

In August 2024, a cross-sectional study was conducted using a self-designed questionnaire based on the core framework of SET through an online questionnaire to assess the willingness of parents in Chengdu to vaccinate children aged 0-6 years with non-EPI vaccines. Multivariable logistic regression analysis was employed to identify factors influencing willingness to vaccinate children with non-EPI vaccines.

A total of 3 448 valid questionnaires were collected, with 46.1% of parents expressing willingness to vaccinate children with non-EPI vaccines. At the micro level, perceived benefits were positively associated with parental willingness to vaccinate their children with non-EPI vaccines (OR=2.60, 95% CI: 2.20-3.07), while risk underestimation was negatively associated with parental willingness (OR=0.68, 95% CI: 0.58-0.79). At the meso level, favorable economic conditions (OR=1.25, 95% CI: 1.07-1.46), good vaccine service accessibility (OR=2.70, 95% CI: 2.31-3.15), and peer recommendations (OR=1.30, 95% CI: 1.11-1.52) were positively associated with parental willingness. Conversely, healthcare workers’ recommendations were negatively associated with parental willingness (OR=0.82, 95% CI: 0.69-0.97). At the macro level, trust in media reports of vaccine-related negative news was negatively associated with parental willingness (OR=0.79, 95% CI: 0.68-0.92), while preferential vaccination policies were positively associated with parental willingness (OR=2.13, 95% CI: 1.75-2.60).

Parents’ willingness to vaccinate children with non-EPI vaccines is influenced by factors at micro, meso and macro levels. Future interventions aimed at increasing vaccination rates for non-EPI vaccines should consider multi-level coordinated interventions.