Large increase in ASD prevalence in Israel between 2017 and 2021

Accurate estimation of annual changes in autism spectrum disorders (ASD) prevalence is critical for planning the expansion of diagnostic, education, and intervention services at an adequate rate. Previous studies from Israel have reported that ASD prevalence among 8-year-old children has increased from estimates of 0.3% in 2008 to 0.65% in 2015 and 1.3% in 2018. Here, we analyzed data acquired from the National Insurance Institute of Israeli (NII), a governmental organization that approves and monitors all ASD children who receive welfare services in Israel, and Clalit Health Services (CHS), the largest Health Maintenance Organization in Israel that provides health services to similar to 52% of the population. Data from both sources included annual data files from 2017 to 2021 containing the number of ASD cases per year of birth for 1-17-year-old children. This allowed us to estimate annual ASD prevalence among 3.5 million children born between 2000 and 2020 in Israel. Both data sources revealed a nearly two-fold increase in ASD prevalence among 1-17-year-old children from 2017 to 2021. Estimated prevalence rates differed across age groups with 2-3-year-old (day-care) children increasing from 0.27% to 1.19% (>4 fold change), 4-6-year-old (pre-school) children increasing from 0.8% to 1.83%, and 8-year-old children increasing from 0.82% to 1.56% in NII data. These results demonstrate that autism prevalence continues to increase in Israel with a shift towards diagnosis at earlier ages. These findings highlight the challenge facing health and education service providers in meeting the needs of a rapidly growing autism population. Lay Summary What is the prevalence of autism in children of specific ages and how has it changed from 2017 to 2021 in Israel? This national study of similar to 3.5 million children, 1-17-years-old, revealed that overall autism prevalence has doubled while prevalence in 2-3-year-old children has increased by a factor of 4.4. These results demonstrate that autism prevalence is increasing rapidly in Israel, particularly at young ages. These findings highlight the need for expanding the availability of services and interventions that will match prevalence changes with a specific focus on early development, where the intervention may have larger impact.