An estimated one in 88 children have autism spectrum disorder, according to the Centers for Disease Control and Prevention. And the number of children with autism has significantly increased in the last 20 years.
Researchers do not yet have a clear understanding as to why the incidence of autism has skyrocketed, but the question as to whether or not routine childhood vaccinations play a role has been raised. Let's take a look at some of the current understanding around this issue.
What are autism spectrum disorders (ASDs)? ASDs are "a group of developmental disabilities that can cause significant social, communication and behavioral challenges" and include diagnoses such as autism and Asperger Syndrome, according to the CDC. Such disorders usually occur by the time a child is three years old, according to the Mayo Clinic.
The incidence of such disorders has been significantly increasing and the exact reason is not known. Experts speculate that the increase may be because the definition of such disorders has been expanded to include more children, or because healthcare and educational professionals and parents are more aware of such conditions and detection and diagnosis is more common, or because there is simply is an increase in such disorders. It is possible that it is a mix of all of these factors.
What causes ASDs? All of the possible causes of ASDs are not known at this point, but researchers say that genes and the environment are main factors. ASDs tend to run in families, so a person may inherit a particular gene that makes it more likely that they will develop such a disorder. If one child in a family has an ASD, their sibling is at greater risk of developing such a disorder as well.
Other risk factors may include certain medications taken during a woman's pregnancy, environmental toxins, dietary factors, lack of prenatal vitamins in the mother during pregnancy, older age of the parents (over 40) when child was conceived, and more. Experts argue that there may not be one single cause of ASDs but rather a mix of things that happen to trigger and cause such conditions.
Could childhood vaccinations play a role? The question as to whether or not childhood vaccinations might add to the incidence of autism has been a hot topic of debate over the last 20 years. Many people have been concerned that children tend to develop autism, ASD symptoms, or worsening of ASD symptoms in a timeframe shortly after receiving multiple routine vaccines that help protect children against illness.
According to the CDC, one particular mercury-containing ingredient of vaccinations known as thimerosal was studied for this link and was removed from vaccines, although there was not conclusive evidence that it contributed to ASD.
The CDC also reports that The Institutes of Medicine reviewed research on vaccines and health outcomes that occur after vaccinations, and in 2011, their report on 8 vaccines given to children and adults found the vaccines to be "generally safe." The IOM stated that "serious adverse events following these vaccinations were rare."
Similarly, a 2013 article in the Journal of Pediatrics concludes that "increasing exposure to antibody-stimulating proteins and polysaccharides in vaccines during the ﬁrst 2 years of life was not related to the risk of developing an ASD."
As a result of these studies and reports, the CDC concludes that "Parents should expect the vaccines their children receive are safe and effective." Many experts state that, in fact, avoiding childhood vaccinations places children in danger of developing serious illness such as whooping cough or measles.
But the ongoing debate about the role of vaccines and autism is probably far from over as there are still other experts that believe vaccinations may trigger autism in some individuals who are susceptible. Many parents of children with ASDs also believe that their child's condition occurred as a result of vaccinations received.
Some experts take the stance that stopping all childhood vaccinations is a dangerous idea for children's health. But experts also recognize that more research is needed to determine which children may be susceptible to risks from vaccinations in order to protect them.
Centers for Disease Control and Prevention.