Until the cause is known, many parents will latch on to the misconception that vaccines cause autism. As a result of the incorrect belief, many parents refuse to vaccinate their children. In the years since the incorrect linkage of autism and vaccines, scientists attempted to surmise the cause of autism. In 2011, scientists conducted a study to see the concordance rates of twins with autism spectrum disorder. Concordance rates are defined as the frequency that both twins exhibit a shared characteristic, in this case, autism. The data indicate that there is a genetic component to autism which refutes vaccines as the primary cause.
Focusing on identical twins, the study analyzed records of twins with autism. Probandwise concordance rates are defined as the likelihood of the co-twin being diagnosed, if the proband, or original patient, is already diagnosed. The concordance rates suggest a moderate correlation between autism and genetics. Higher probandwise rates imply that if one twin is diagnosed with autism, it is likely that the other twin will be diagnosed too. If there were no genetic component to autism, concordance rates would be the same for all identical twins analyzed. Some may argue that the likelihood of the female co-twins having autism is not substantial evidence because the frequency is only 0.5. However, 0.5 concordance shows that twin girls are more likely to get Autism than you would expect, which shows genetics are partially responsible for autism. Therefore, environmental factors such as vaccines cannot be the only factor contributing to autism. The concordance data do not eliminate vaccines as a cause of autism, but they do show that vaccines are not the only factor.
Some parents blame vaccines for their children’s autism, but these concordance data show that genetics play an important role in autism. With these data, researchers might be able to discover which genetic variations lead to autism. As the genetic connection to autism is recognized the general public, reduced anti-vaccine sentiments might contribute to more parents vaccinating their children and protecting them from deadly diseases.
*Hallmayer et al. Arch Gen Psychiatry Vol. 68 No.11, 2011.