By: Dr. Gabriel Andrade
Every once in a while I hear the claim that vaccines and autism are related. This needs some clarification.
For the past two decades, there has been concern about an apparent increase in the epidemiology of autism. Researchers are not sure whether this is a real phenomenon. It actually appears to be that, as the public is becoming increasingly educated and there is higher awareness, (in large measure due to more media exposure), of Autism Spectrum Disorder, it is more frequently diagnosed now. In the past it may have been present, but parents were not aware that it is in fact a neurodevelopmental disorder, and it may have been significantly underdiagnosed.
This is only a working hypothesis, and there have been other attempts to explain the rise of autism cases over the last 20 years. In 1998, a well-publicized study ventured to explore some causal factors that turned out to be very controversial.
Dr. Andrew Wakefield, along with 12 other authors, published an article reporting the case studies of 12 children in the United Kingdom. These children were diagnosed with some developmental disorders, autism being the most common. The children’s parents reported that they began to notice the symptoms of developmental disorders in children soon after receiving administration of the Measles Mumps and Rubella (MMR) vaccine.
Wakefield then proceeded to perform intestinal biopsies on the subjects, and the results came out positive for inflammation. According to Wakefield et al, vaccines were causing this intestinal inflammation. The proposed mechanism was as follows: due to intestinal inflammation, proteins from nutritional intake can make their way to the brain, thus causing autism.
The study had some considerable methodological flaws. Some of the patients’ parents reported that their children had symptoms of autism before symptoms of bowel disease. This fact does not cohere well with Wakefield’s theory. If autism is a result of intestinal inflammation, then it would be normal to expect that symptoms of the latter would actually appear first; yet, that was not the case.
Wakefield never specified which protein is the cause of autism. He ventured to claim that, due to intestinal inflammation, the protein would make its way to the brain, but he was never precise as to what the particular protein may be. No researcher has been able to to identify that hypothetical protein.
Some other studies have found evidence that again does not cohere well with Wakefield’s original hypothesis. Vaccination rates have been steady, yet the incidence of autism has increased. If vaccines were truly the cause of autism, we should expect that, along with the rise of autism rate, there should have been a rise of vaccination rates. Yet, that is not the case.
Further studies have failed to find evidence in support of Wakefield’s original hypothesis. A study of 473 children in London comparing vaccinated and unvaccinated cohorts, did not find an association between developmental disorders and gastrointestinal symptoms. A cross sectional study of 262 children diagnosed with autism found no relationship between the diagnosis and appearance of symptoms after the administration of the MMR vaccine. In yet another study done in the United Kingdom, 71 children were subject to thestudy, and no causal link between autism and vaccines was found.
Perhaps the most complete study on the relationship between autism and vaccines was a Finnish study of 1.8 million children who received the MMR vaccine. The study did not find a single case of autism related to vaccines. These studies provide massive data that vaccines do not cause autism, especially when compared to the 12 cases on which Wakefield’s study relied.
Furthermore, it later became public that there were very serious ethical issues with Wakefield’s original study. In 2004, 10 of the authors of Wakefield’s original article retracted. According to some journalistic investigations by Brian Deer, Wakefield received financial incentives from lawyers of parents of autistic children, who had the intention of taking legal action against the companies that manufactured the MMR vaccine. Wakefield never disclosed this conflict of interest. Furthermore, Wakefield had the intention of registering a patent for a vaccine that, if launched in the market, would have competed with the conventional MMR vaccine. Wakefield was also accused of needlessly performing lumbar punctures on three of the children he studied, and of selectively choosing subjects for his study, in order to make sure that he would get the results he anticipated.
In light of these ethical misconducts, Wakefield was ultimately removed from the Medical Registry in the United Kingdom. The Lancet (the journal in which Wakefield’s article was originally published) then retracted the original article.