Infant Vaccine Scheduling Intensity and Autism Incidence: A Preliminary Cross-National Analysis to Guide Public Health Policy
Abstract
This study explores the association between early-life vaccine scheduling intensity and autism prevalence across 12 high-income countries, aiming to inform evidence-based public health policy. We examined whether the number and timing of vaccine doses administered to infants under one year correlate with standardized autism incidence rates. Using cross-national data from countries with comparable healthcare systems and diagnostic standards, we applied descriptive statistics, partial correlations (controlling for overall vaccination coverage), and multivariate regression models. Nations with higher autism prevalence (USA, Canada, Australia, Japan, South Korea, Singapore) averaged 15 vaccine types and 20 doses for infants ≤1 year, whereas lower-prevalence countries (Norway, Denmark, Finland, Italy, Sweden, UK) averaged 8 vaccines and 9 doses. Partial correlations revealed strong positive associations between autism prevalence and both vaccine types (r = 0.87, p < 0.001) and doses (r = 0.79, p < 0.01). Regression analysis indicated that a 1% increase in vaccine types corresponded to a 0.47% increase in autism prevalence (p = 0.001), explaining 81% of variance. While these findings do not establish causality, they identify patterns warranting further investigation. For practitioners and policymakers, these results underscore the importance of evaluating vaccine scheduling strategies alongside developmental outcomes. More gradual schedules, as observed in countries with lower autism prevalence, may merit consideration in future research and policy discussions to optimize neurodevelopment while maintaining high immunization coverage. This study provides actionable insights for disease prevention and health promotion professionals seeking to balance immunization goals with long-term child health outcomes.
