Many people are aware of the controversy regarding vaccines that has swept the nation in the past 14 years. By my father’s suggestion, I performed my own research into the matter so that I could draw my own conclusions based on the scientific evidence. Rather than looking at web forums and blogs, which tend to be looking for something to blame and offer anecdotal evidence rather than reproducible statistical studies, I chose to look at scientific journals.
Before getting into things, I would like to point out that I am not a professional researcher and do not have the kind of time to devote to writing a proper summary of my findings. I have not thoroughly summarized the research, but instead have hand picked examples which could be easily summarized. There is a lot of other data out there to look at, which I encourage you to do. I am a secondary source and am providing no new data, so do not take anything I say here as fact without performing your own investigations.
When I began my research into the theory that vaccinations can cause autism, the bulk of what I was finding related to the MMR vaccine, though late in my research I also discovered that there was fear with regard to the preservative thimerosal, which contains mercury, that has been in use in the vaccines since, to my recollection, the 40′s (don’t take this at face value: I have no citation for it because I did not think it was important enough to note before I wrote this). Having already spent an entire day working on this subject, I did not wish to dig into the existing research around this preservative, because I determined that since 2001 there has been no cause for concern in the United States.
According to the FDA, there is insufficient evidence to support the claim that thimerosal causes autism. “However, depending on the vaccine formulations used and the weight of the infant, some infants could have been exposed to cumulative levels of mercury during the first six months of life that exceeded EPA recommended guidelines for safe intake of methylmercury.” As a precautionary measure, since 2001, “all vaccines manufactured for the U.S. Market and routinely recommended for children <= 6 years of age have contained either no thimerosal or only trace amounts (<= 1 microgram of mercury per dose).”[1] In other words, as this is no longer used, investigating the research available is, for the most part, a moot point.
However, there still exists the theory that the MMR vaccine causes autism. This notion seems to have been created by Andrew Wakefield and 11 of his peers in a 1998 article titled Illeal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children, published in The Lancet[2]. This study examined 12 children in depth and among other claims, it was suggested that within days of administration of the MMR vaccine, these children were demonstrating signs of autism.
This was indeed a shocking revelation, and others sought to perform their own research to investigate this claim. A 1999 article by Brent Taylor et al., titled Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association, describes a study which they carried out by statistically analyzing children with autism who had been born since 1979 in eight North Thames health districts in the UK[3]. 498 cases of autism diagnoses were identified, though only 293 were confirmed based on the criteria laid out by the ICD-10. (The link is provided for convenience to give an overview of the topic, and does not constitute a valid scholarly reference.) Of these confirmed cases, it was concluded that there is no “causal association between MMR vaccine and autism. If such an association occurs, it is so rare that it could not be identified in this large regional sample.” In other words, not only does this study demonstrate that the MMR vaccine did not cause autism, if there is any association between the two, it was not evident with the data collected.
In 2002, Kreesten Madsen et al. published an article in the New England Journal of Medicine titled A population-based study of measles, mumps, and rubella vaccination and autism[4]. In their study, they investigated the records of all children born in Denmark from 1991 through 1998. Of the 537,303 children examined, 82% received the MMR vaccine, and the set of those who were vaccinated was compared against those who were not. There was no statistical difference in the rate of autism among either group. They conclude that they have presented “strong evidence against the hypothesis that MMR vaccination causes autism.”
Despite these additional studies, there still existed debate over the topic. In a 2004 letter to the editor of Lancet, 10 of the 12 authors of the original article clarified that the original article did not demonstrate that the MMR vaccine caused autism, and that it was instead speculating at the possibility of a link which required further research[5]. Of the two who did not participate in this clarification, one was unable to be contacted, and the other was Wakefield, the lead author.
While this should, at the very least, quell any particular furor related to the theories surrounding this vaccine, misinformation had already been ingrained in many people. Brian Deer, a British investigative reporter, spent many years investigating the claims of Wakefield, and determined that data was both unethically obtained and falsified for his 1998 article[6]. He also exposed that Wakefield was involved in litigation against the makers of the MMR vaccine in which 11 of the 12 children in his study were plaintiffs, posing as a serious conflict of interest. While this data is not presented in a sufficient manner to come to a scientific conclusion, evidence that was presented before a UK court found these accusations to be true, and Wakefield was stripped of his license to practice medicine.
Thus, I have come to the conclusion that, generally speaking, vaccines are not something that people should be afraid of. Give your children immunity to diseases, they’ll thank you for it later. (They may night verbally thank you for it, but they will enjoy going through life not developing polio, measles, diphtheria, etc.) To clarify this, it has not been shown that specific vaccines do not have problems, but rather that the general fear linking autism to vaccines has no merit.
What can we take away from all of this? When reading the claims of others on the Internet, I always ask myself, “what is the source of this information?” My experience is that most people who post things on the Internet are “armchair experts,” who like to pass along their version of reality and cannot provide citations for anything they say. I encourage all who read this to perform scholarly research into controversial scientific topic. To reiterate what was stated at the beginning, that means no blogs and very few websites, but peer-reviewed journals. Your local university library should have access to many such resources. You can use the articles summarizing the research of others to find original sources, but don’t put your faith in these secondary sources either.
Note on comments: all comments on this blog must be approved before being publicly visible. Any comments with claims that are either not backed up or are backed up with non-scholarly resources will not be approved. Please offer any corrections or suggestions for clarification that can be made here, though again, if you do not properly cite your reasoning your comment will be ignored.
Citations
- FDA. Thimerosal in vaccines questions and answers. Web site. http://www.fda.gov/BiologicsBloodVaccines/Vaccines/QuestionsaboutVaccines/UCM070430. Accessed Feb 11, 2012.
- Andrew J. Wakefield, et al. (1998). Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet, 351(9103), 637.
- Brent Taylor, et al. (1999). Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association. Lancet, 353(9167), 2026.
- Kreesten M. Madsen, et al. (2002). A population-based study of measles, mumps, and rubella vaccination and autism. New England Journal of Medicine, 347, 1477.
- Simon H. Murch, et al. (2004). Retraction of an interpretation. Lancet, 363(9411), 750.
- Brian Deer. Brian deer: the lancet scandal. Web site. http://briandeer.com/mmr-lancet.htm. Accessed Feb 11 2012.