The Moderating Role of Demographic Variables in the Effect of Health Literacy on Anti-Vaccination Sentiment

Background/Objective: Vaccine hesitancy continues to pose a challenge to public health, and health literacy has been suggested as a potential factor influencing vaccination attitudes. However, the nature of this relationship and the role of sociodemographic characteristics remain to be clarified. This study aimed to examine the association between health literacy and vaccine refusal and to explore whether this relationship is moderated by education level, age, income, place of residence, and gender. Methods: A cross-sectional nationwide online survey was conducted among 413 adults living in Türkiye. Data was analyzed using SPSS version 22. Distributional assumptions were evaluated using the Kolmogorov–Smirnov test together with skewness and kurtosis values. Moderation analyses were performed using Hayes’ PROCESS macro (Model 1), and statistical significance was set at p < 0.05. Results: The study included 413 participants, most of whom were aged 18–30 years (62.7%) and female (69.3%). Health literacy showed a statistically significant negative association with vaccine refusal (β ranging from −0.30 to −0.72, p < 0.001). Education level was identified as a significant moderator (R2 = 0.14), indicating that the strength of this association varied across educational groups. Specifically, the inverse relationship appeared more pronounced in individuals with lower educational attainment and attenuated at higher education levels, becoming non-significant in the postgraduate group. In contrast, age, income, place of residence, and gender did not demonstrate consistent or statistically robust moderating effects. Although rural residence was associated with higher vaccine refusal levels, it did not significantly modify the relationship between health literacy and vaccine refusal. Conclusions: The findings suggest that higher health literacy is associated with lower vaccine refusal; however, this relationship appears to vary by educational level. The modest explanatory power of the models indicates that health literacy alone may not fully account for vaccine-related attitudes. Further research incorporating additional behavioral and contextual factors is warranted to better understand the determinants of vaccine refusal.