The history of autism is partly built on myths and controversy, some of which have shaped societal attitudes, while others have been enshrined as facts without proper investigation. Needless to say, such attitudes have often led to disastrous effects on the lives of people with autism and their families. In this first instalment of ‘Autism: Myths and facts’, we will put forward some controversial myths about autism that require further clarification.
Myth #1. Childhood vaccines are the major reason for the increase in autism numbers
One of the greater controversies surrounding Autism Spectrum Disorder (ASD) is centred on whether a link exists between the condition and certain childhood vaccines, particularly the measles-mumps-rubella (MMR) vaccine. A quick online search turns up plenty of comments from concerned parents and anti-vaccination activists pointing their accusatory fingers. A number of these comments cite a 1998 study linking the MMR vaccine to a hypothetical bowel disorder dubbed autistic enterocolitis. Eventually, this paper was retracted and disowned by its co-authors due to gross misinterpretation of data. In 2011, an editorial published in the British Medical Journal labelled this study as an “elaborate fraud”.
Despite the body of evidence that refutes the idea that vaccines cause autism, many parents still decide against having their children immunized, thus placing their children in danger of contracting and spreading serious diseases, including whooping cough, measles or mumps. Not surprisingly, there have been totally avoidable measles outbreaks in recent years, including a recent one in Disneyland, California, and which led to school closures and quarantine measures.
Another reason why people are still concerned with vaccine safety might be the fact that there has been a noticeable increase in autism prevalence in recent years. Many doctors and epidemiologists attribute this to greater disease awareness, leading to increased diagnosis. It is worth noting that until the early 1980s, “autism spectrum” was not a diagnostic category, and it was only in the late eighties that autism was accepted as a developmental disability that lasts a lifetime.
It is worth noting that as a precautionary measure, the US Food and Drug Administration (FDA), National Institutes of Health (NIH), Center for Disease Control and Prevention (CDC), and Health Resources and Services Administration (HRSA), and the American Academy of Pediatrics had issued two Joint Statements, urging vaccine manufacturers to reduce or eliminate the mercury-based preservative thimerosal in vaccines as soon as possible (CDC 1999) and (CDC 2000). In so doing, thimerosal, which many have blamed for the possible autism link, has fallen long out of favor.
A major study published in 2015 in the Journal of the American Medical Association (JAMA) included data from 95,727 children, 2% of whom had an older sibling with ASD. In this large sample of children with older siblings, receipt of the MMR vaccine was not associated with increased risk of ASD, regardless of whether older siblings had ASD. These findings indicate no harmful association between the MMR vaccine and ASD even among children already at higher risk for ASD.
One hopes that this study will put such claims against vaccination to rest, even though until science uncovers potential triggers for autism, doubts will occasionally resurface. In the meantime, we can rest assured that plenty of research is being carried out in trying to elucidate potential genetic and environmental causes of autism.
Godlee F. Wakefield’s article linking MMR vaccine and autism was fraudulent (Editorial). BMJ 2011;342:c7452
Jain A, Marshall J, Buikema A, Bancroft T, Kelly, JP, Newschaffer CJ. Autism Occurrence by MMR Vaccine Status Among US Children With Older Siblings With and Without Autism. JAMA 2015; 313(15):1534-1540.
Centers for Disease Control and Prevention. Notice to Readers: Thimerosal in Vaccines: A Joint Statement of the American Academy of Pediatrics and the Public Health Service. Morb Mort Wkly Rep 1999; 48:563-565.
Wakefield AJ, Murch SH, Anthony A, Linnell, Casson DM, Malik M, et al. Ileal lymphoid nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children [retracted]. Lancet 1998; 351:637-41.