Despite persistent public concern, extensive scientific research has consistently found no credible link between vaccinations and autism spectrum disorder. For example, a large-scale study compared the vaccination histories of children with ASD to those of a control group, specifically examining the total number of immunogens (substances that trigger an immune response) received in the first two years of life. The findings clearly showed that the quantity of immunogens was not related to the development of ASD, reinforcing the broad scientific consensus that vaccines are not a cause of the disorder.