Parental vaccine hesitancy in primary care in Bilecik, Türkiye: associations with health beliefs and 5C psychological antecedents—a cross-sectional study

This study examined the associations of health beliefs and 5 C psychological antecedents with vaccine hesitancy among parents of children aged 0–6 years and evaluated four theory-informed interactions. This cross-sectional study included 350 parents recruited consecutively within centre-specific quotas at six randomly selected Family Health Centres in Bilecik, Türkiye, between October 2025 and April 2026. Validated Turkish scales assessed vaccine hesitancy, Health Belief Model dimensions and 5 C antecedents. Analyses included correlations, group comparisons, hierarchical regression and covariate-adjusted moderation models. Holm adjustment was applied to four primary interaction tests. The mean vaccine hesitancy score was 21.71 ± 7.70. Vaccine hesitancy was most strongly inversely correlated with confidence ( r = -0.777) and was positively correlated with perceived barriers ( r = 0.510), complacency ( r = 0.327), and constraints ( r = 0.201). The final hierarchical model accounted for 68.0% of the variance after adjustment for model complexity (adjusted R² = 0.680). Confidence had the largest absolute standardised coefficient and was inversely associated with vaccine hesitancy (B = -0.917, β = -0.551, p < 0.001). The interactions between perceived benefits and confidence (B = -0.0278, ΔR² = 0.0071) and between perceived barriers and constraints (B = -0.0465, ΔR² = 0.0273) explained an additional 0.7% and 2.7% of the variance, respectively. Neither interaction remained statistically significant after Holm adjustment (adjusted p = 0.089 and 0.053, respectively); these patterns should therefore be regarded as exploratory rather than established moderation effects. Among parents attending Family Health Centres in Bilecik, vaccine hesitancy was associated with health beliefs and 5 C psychological antecedents. The association with confidence should be interpreted in light of its conceptual overlap with the hesitancy measure. The high explained variance does not establish strong independent predictive ability. These findings may inform the development and evaluation of parent-centred primary care approaches addressing trust and perceived barriers. The small incremental contributions of the interaction terms and the cross-sectional design warrant cautious interpretation. Longitudinal and intervention studies using behavioural vaccination outcomes are needed to clarify the direction and public health relevance of these associations.