In "A Positive Association Found Between Autism Prevalence and Childhood Vaccination Uptake Across the U.S. Population" published in the May 2011 issue, pages 903-916 in the Journal of Toxicology and Environmental Health, Part A, researchers suspect that one or more environmental triggers could be a cause in the development of autism. One of those triggers might be the battery of vaccinations that young children receive.
The relationship between the proportion of children who received the recommended vaccines by age 2 years and the prevalence of autism (AUT) or speech or language impairment (SLI) in each U.S. state from 2001 and 2007 was determined. A positive and statistically significant relationship was found: The higher the proportion of children receiving recommended vaccinations, the higher the prevalence of AUT or SLI. These results suggest that there may be a link of vaccines to autism.
In "Hepatitis B Vaccination of Male Neonates and Autism Diagnosis," published in the November 2010 issue, pages 1665-1677 in the Journal of Toxicology and Environmental Health, Part A, researchers have found an association between hepatitis B vaccination of male neonates and parental reports of autism.
This research included a study among boys age 3-17 years, born before 1999, who were vaccinated for hepatitis B as neonates. Boys vaccinated as neonates had threefold greater odds for autism diagnosis compared to boys never vaccinated or vaccinated after the first month of life.