PURPOSE: The Autism and Developmental Disabilities Monitoring (ADDM) Network estimates the prevalence of autism spectrum disorder (ASD) throughout the United States. Reports through 2010 found higher prevalence in areas of higher socioeconomic status. Reports since 2018 indicate a pattern change. We used CDC's Social Vulnerability Index (SVI) to examine the association of ASD prevalence and social vulnerability in ADDM Network sites. METHODS: Cases of ASD among 8-year-old children in 2020 were linked to SVI measures and population estimates. Tracts were categorized into tertiles (high, medium, and low) and prevalence, prevalence ratios (PRs), and 95 % confidence intervals (CIs) were calculated. RESULTS: Among 5998 children with ASD, we saw higher ASD prevalence in areas with high versus low vulnerability overall (26.18 per 1000
PR=1.06 (1.00-1.13)) and in areas with more minority residents (28.28 per 1000
PR=1.29 (1.21-1.38)), less transportation (27.32 per 1000
PR=1.13 (1.06-1.20)), and greater disability (26.83 per 1000
PR=1.09 (1.02-1.17)). This pattern was observed among White children (PR=1.48 {1.36-1.60}) but reversed among Black (PR=0.61 {0.53-0.70}), Asian (PR=0.58 {0.46-0.73}), and Hispanic (PR=0.83 {0.72-0.95}) children. CONCLUSIONS: Disparities in prevalence of ASD by neighborhood-level social vulnerability persist. Directing resources toward providing equitable access to healthcare and support services could help close this gap.