Vaccines and ASD
Jain, A., Marshall, J., Buikema, A., Bancroft, T., Kelly, J. P., & Newschaffer, C. J. (2016). Autism occurrence by MMR vaccine status among US children with older sibling with and without Autism. JAMA,313(15), 1534-1540.
McKee, C. & Bohannon, K. (2016). Exploring the reasons behind parental refusal of vaccines. The Journal of Pediatric Pharmacology and Therapeutics, 21(2),104-109. Health Communication, 34(1),110-117.
Mo Jang, S., Mckeever, B. W., Mckeever, R., &Kyoung Kim, J. (2019). From social media to mainstream news: The information flow of the vaccine-autism controversy in the US, Canada, and the UK.
Sathyanarayana Rao, T. S., &Andrade, C. (2011). The MMR vaccine and autism: sensation, refutation, retraction, and fraud. Indian Journal of Psychiatry, 53(2), 85-96.
Do vaccines cause Autism Spectrum Disorder (ASD)?
There have been a number of studies debunking the link between vaccines and ASD. The speculation that vaccines cause ASD is complicated by the fact that many of the signs of ASD are detected or begin to emerge at similar ages as when most vaccines are delivered, particularly the MMR sequence. Some proponents of the vaccine-ASD theory have stated that vaccines themselves cause ASD, while others have argued that preservatives in vaccines are to blame. Both vaccines and preservatives in vaccines (many of which have been reduced or removed from vaccines since the debate began, such as is the case with thimerosal) have been repeatedly shown in the research literature to be unrelated to the prevalence of ASD.
For example, one study from 2016 by Jain and colleagues used existing health data collected from 95,727 children to examine if there was an association between receiving an MMR vaccine (1 or 2 doses) and later being diagnosed with ASD. The percentage of children later diagnosed with ASD was similar between those that did not get vaccinated and those who did get the MMR vaccine (regardless of dose). This means that receiving the MMR vaccine did not increase the likelihood of being diagnosed with ASD. Interestingly, this was also the case for children with an older sibling with ASD. Although children with an autistic sibling are generally at a higher risk for being diagnosed with ASD, receiving an MMR vaccine did not make a diagnosis more likely. While this is only one study, there are many other studies like it focusing on different vaccines and vaccine preservatives with similar results.
Where did the vaccine myth come from?
Andrew Wakefield and colleagues published a study in 1998 in the Lancet that suggested a link between vaccines and ASD. This study was highly publicized in the media but later was retracted (i.e., the journal where this study was published examined the study more closely and determined the findings were incorrect and misleading; 10 of the 12 co-authors on the paper also came forward to state there was insufficient information to establish a causal link between ASD and vaccines). Unfortunately, the investigations into the team’s research found many problems, including that the authors had committed deliberate fraud and failed to disclose financial interests that may have affected the outcomes reported in the study. Specifically, it was found that Wakefield and his team chose data from their study that matched the vaccine-ASD theory and left out data that didn’t agree with this theory. Wakefield was also reported to have been funded by two lawyers who had been involved in anti-vaccine lawsuits. Given this, ethical and legal repercussions followed for this research team. However, despite the attempt to remove this faulted research from circulation, the impact on the general public’s opinion of vaccines remains given the widespread media attention it received initially.
Why are we still talking about a vaccine-ASD link if it is a myth?
Vaccination is a very controversial topic in our world today. A review paper by McKee and Bohannon (2016) sought to summarize prior research on the reasons that parents have given if they refuse, delay, or are hesitant to vaccinate their children in general. The four themes they found in their study included religious reasons, personal beliefs or philosophical reasons, safety concerns, and a sense that they don’t have enough information from healthcare providers to make informed decisions about vaccination. Given the wide array of reasons, and the vast differences between decisions parents make about refusing or delaying despite sharing the same general reason, the topic boils down to it being a very personal matter.
Despite the personal nature of such a decision, as is the case with any health-related choice, it also has a community impact. In January 2017, the American Academy of Pediatrics reissued their statements on emphasizing the safety and importance of vaccination. A statement by Fernando Stein, MD, FAAP, President, American Academy of Pediatrics, and Karen Remley, MD, MBA, MPH, FAAP, CEO/Executive Vice President, American Academy of Pediatrics (https://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/American-Academy-of-Pediatrics-Emphasizes-Safety-and-Importance-of-Vaccines.aspx) indicated:
“Claims that vaccines are linked to autism, or are unsafe when administered according to the recommended schedule, have been disproven by a robust body of medical literature. Delaying vaccines only leaves a child at risk of disease. Vaccines keep communities healthy, and protect some of the most vulnerable in our society, including the elderly, and children who are too young to be vaccinated or have compromised immune systems.”
Also, in recent years, there has been an increase in using social media (e.g., Twitter, Reddit, Facebook) to share health and science information. As is the case with all information found online, some of it is accurate and some of it is incorrect. Research by Mo Jang and colleagues (2019)found that anti-vaccine proponents are more likely to discuss vaccines on social media than those supporting vaccine use. Additionally, some social media platforms were found to influence mainstream news and the vaccine-autism controversy was more “popular” among posts that didn’t include links to information supporting the posts. The authors concluded that misleading information on social media could be particularly problematic because “popular information may artificially inflate support for unverified claims.” In other words, the decisions people might be making about vaccines could be based on misinformation, which doesn’t provide a fair base to evaluate best options.
Are there any reliable easy-to-read resources out there about vaccines to better understand this topic?
American Academy of Pediatrics – Immunizations
- This site provides basic information on immunizations, recommended schedules, how to communicate about vaccines, and information for parents about vaccines. It also features updates and data summaries by state for the US.
World Health Organization – Immunization
- This site provides basic information on immunizations as well as World Health Organization papers related to policy recommendation as part of the “Health Topics” feature on the WHO website.
Centers for Disease Control and Prevention – Vaccines & Immunizations
- This site provides information about vaccination across the lifespan and provides a number of resources for accurate information about immunization. Vaccine Information Statements (VISs) were also available at this site as of August 2019, which provide information about various vaccines with reasons for immunization with that specific vaccine, reasons why some people should not receive that vaccine, risks involved, guidance for what to do if a reaction to a vaccine occurs, and contact information for theNational Vaccine Injury Compensation Program as well as the CDC. Most parents will have received these sheets during routine vaccinations at their child’s healthcare provider’s office.
Autism Science Foundation-Autism and Vaccines
- The Autism Science Foundation is a nonprofit corporation with the mission to support high quality ASD research via funding and other assistance. Their overall website has information about the foundation, ASD generally, funding, and leadership. The link above provides many resources, including access to a PBS NOVA video about vaccination and various articles to better understand the research related to ASD and vaccines.