Determinants of Childhood Vaccination Non-Adherence in Sunampe, Peru: A Cross- Sectional Study on Coverage, Parental Concerns, and Mortality

Background The Sunampe district on the Peruvian coast faces challenges related to adherence to childhood vaccination schedules. This study aimed to assess whether non-compliance with vaccination correlates with an increased risk of vaccine-preventable disease outbreaks among children under five, within the context of low coverage in Sunampe. Methods A descriptive, correlational, cross-sectional study was conducted involving 123 families in Sunampe. Data on vaccination status, reported illnesses, and mortality of children aged 1 to 5 years were collected. Medical records were reviewed for vaccine-preventable diseases, and mortality data were obtained from the SINADEF database. To identify factors associated with vaccine non-compliance, forward selection logistic regression was applied to 25 survey questions (Q1–Q25), each treated as a dependent variable, using a p-value threshold of 0.05. Results Neighboring districts had more health facilities, while families in Sunampe perceived the single local health center as insufficient. No active vaccine-preventable illnesses were reported among surveyed children, but SINADEF data showed 10 deaths in children under five between 2017 and 2022. Also, it was shown the prevalence of illness and incomplete immunisation, as well as increased rates of anemia in Peru. Logistic regression models had limited predictive power (low AUC values). However, forward selection revealed significant associations among questionnaire items, notably family objections to vaccination (Q22), early vaccination discontinuation (Q02–Q05), ease of access (Q09), and parental knowledge of immunization schedules (Q14, Q17). Conclusion Incomplete vaccination in Sunampe appears linked to parental knowledge gaps and concerns about vaccine side effects, despite most parents reporting no severe reactions. These findings highlight the need for targeted education to improve vaccination adherence and reduce outbreak risks. An event-related study design is suggested to investigate discrete neurophysiological or behavioral responses linked to vaccination events.