Addressing childhood vaccine hesitancy using an online decision aid: a longitudinal evaluation

Abstract Background The uptake of childhood vaccinations is declining, resulting in an increase in vaccine-preventable diseases, such as measles. Many parents make decisions about vaccination before their child is born. Yet, vaccination counseling typically begins after childbirth. We co-developed a parent-facing decision aid (PDA) to inform and support prospective parents in making decisions about their child's vaccinations, tailored to the needs of parents with low health literacy, who are known to be more hesitant. Our objective is to study the use and usefulness of the PDA to (prospective) parents . Methods We conducted a longitudinal observational study. We recruited participants between 14 and 22 weeks of pregnancy and will follow them until four months postpartum. Throughout the study period, we provide access to the PDA and monitor individual use through activity logs. At baseline, during pregnancy, and after childbirth, participants complete questionnaires assessing usefulness of the PDA, their stage of decision-making, vaccine hesitancy, intention to vaccinate, and decisional conflict. We will also collect data on vaccine uptake when their infants are 6 months old. In addition, we will conduct in-depth interviews with a sample of parents to explore the perceived usefulness of the PDA. Results We included 398 pregnant women or their partners, 75% of whom were first-time parents. At baseline, 49% had not made a definitive decision about vaccination, of which 56% were vaccine hesitant compared to 30% in the overall study population. User activity logs show variable use, ranging from short interactions to more extensive use of the PDA lasting for several minutes. In November 2025, we will present preliminary quantitative and qualitative results. Conclusions The results of this study will provide insight into how parents use and react to the PDA about childhood vaccination.