Objective To investigate the willingness of parents of children in Anshun city, Guizhou province, to participate in supplementary insurance for adverse events following immunization (AEFI) (hereinafter referred to as supplementary insurance) and its influencing factors.

Methods From March to June 2024, a stratified random sampling method was used to select 14 vaccination clinics from seven counties (districts) in Anshun city. Questionnaires were administered to 1 634 parents of children aged 0-1 year and 14 medical staff. A two-level logistic regression model and random forest analysis were used to analyze the factors influencing parents′ willingness to participate in the insurance.

Results The willingness of parents to participate in supplementary insurance was 56.90%. Two-level logistic regression analysis showed that parents′ willingness to participate in the insurance was clustered at the vaccination clinic level. The length of time vaccination clinic staff were responsible for education work (1 year - < 2: OR = 1.697, 95%CI: 1.241 - 2.320; ≥ 2 years: OR = 2.061, 95%CI: 1.328 - 3.198), and the presence of insurance company staff on-site to assist with education (OR = 1.443, 95%CI: 1.039 - 2.004) positively influenced parents′ willingness to participate. Having three or more education staff at the vaccination clinic (OR = 0.635, 95%CI: 0.464 - 0.868) negatively influenced parents′ willingness to participate. At the individual level, educational level (junior high school: OR = 1.544, 95%CI: 1.015 - 2.351; senior high school or secondary vocational school: OR = 1.994, 95%CI: 1.240 - 3.207; junior college: OR = 2.319, 95%CI: 1.410 - 3.814; bachelor′s degree or above: OR = 2.217, 95%CI: 1.317 - 3.731), monthly household income (¥5000 - < 8000: OR = 1.629, 95%CI: 1.159 - 2.289; ¥8000 - < 10000: OR = 1.787, 95%CI: 1.044 - 3.058), having purchased other insurance for their children (OR = 2.801, 95%CI: 1.886 - 4.160), understanding of AEFI (OR = 1.612, 95%CI: 1.133 - 2.294), and having received information about the compensation insurance policy during maternity care (OR = 1.551, 95%CI: 1.039 - 2.313) positively influenced parents′ willingness to participate. Grandparents or other relatives being the primary caregiver (OR = 0.539, 95%CI: 0.297 - 0.978), belonging to an ethnic minority group (OR = 0.763, 95%CI: 0.599 - 0.973), and having two or more children (OR = 0.688, 95%CI: 0.546 - 0.868) negatively influenced parents′ willingness to participate. Random forest results showed that the top five factors influencing parents′ willingness to participate were parental education level, monthly household income, having purchased other insurance for their children, length of time responsible for education work, and level of understanding of AEFI.

Conclusions The willingness of parents in Anshun city to participate in supplementary insurance for AEFI is relatively low. Influencing factors include those at both the individual parent level and the vaccination clinic level. Measures should be taken at multiple levels to increase parents′ willingness to participate.