Knowledge as a predictor of parental vaccine hesitancy during children's first year of life

To analyze knowledge about childhood vaccination as a predictor of vaccine hesitancy among parents or guardians of children in the first year of life.

This cross-sectional analytical study was conducted in Piauí, Brazil, with 452 parents or guardians of children in the first year of life, selected by cluster sampling. Data were collected in 2025 through household interviews using an adapted and previously validated form. Knowledge was assessed using six questions and classified as low, moderate, or high. Vaccine hesitancy was defined as at least one response compatible with any dimension: confidence, complacency, convenience, communication, or context. Descriptive and inferential analyses were performed. Logistic regression was used with vaccine hesitancy as a dichotomous dependent variable (yes/no), estimating crude and adjusted odds ratios with 95% confidence intervals and a 5% significance level in the final model.

Most children were aged zero to six months (78.5%) and were male (52.2%). Most parents or guardians were female (88.5%) and had non-White race/skin color (82.7%). Moderate knowledge was most frequent (55.8%), followed by high knowledge (35.4%). Overall vaccine hesitancy occurred in 31.4% of parents or guardians, with 25.2% specific to the COVID-19 vaccine and 6.2% related to other vaccines in the childhood immunization schedule. Parents or guardians of children aged seven to 12 months had higher odds of vaccine hesitancy (aOR: 2.16; p = 0.002), whereas higher education (aOR: 0.79; p = 0.038) and high knowledge (aOR: 0.39; p = 0.015) were associated with lower odds of hesitancy.

Vaccine hesitancy among parents or guardians of children in the first year of life was substantial and mainly related to COVID-19 vaccination. Lower odds among those with high knowledge and higher education reinforce that understanding childhood vaccination, especially vaccine-preventable diseases, safety, and expected reactions, is important for vaccine adherence during this period.