The near eradication of many diseases by vaccination is one of the greatest scientific and public health achievements of the twentieth century. And this was not merely a result of better hygiene and sanitation as claimed by some. One by one, smallpox, diphtheria, pertussis, tetanus, polio, measles, mumps, rubella and other scourges of mankind were beaten back as scientists discovered how to coax our immune systems to make antibodies against the pathogens that cause these diseases. Among the chief beneficiaries of this improvement in the health of our population were children. If you go to old cemeteries and check the graves, you will find a much larger number of children’s graves compared to modern cemeteries. Therefore it seems somewhat paradoxical that nowadays in our society and others a significant group of parents have refused to vaccinate their children claiming among other things that vaccines cause autism. This in turn has led to a resurgence of some of these diseases such as the measles outbreaks in California in 2014, Arizona in 2016, and the recent outbreak in Minnesota. What is happening here?
First of all, what is autism? Autism, or more accurately autism spectrum disorder (ASD), is a neurodevelopmental disorder where the afflicted children exhibit a lack of social interaction. Autistic children are withdrawn as if living in their own world, and many exhibit mental retardation, hyperactivity, irritability and repetitive behaviors. The specific cause of ASD is not known but it seems to encompass both genetic and environmental factors.
Now, how did autism ever become associated with vaccines?
The strongest catalyst for this association was an article published in 1998 by Dr. Andrew Wakefield and 12 other researchers in the medical journal the Lancet which suggested a link between the measles, mumps, and rubella (MMR) vaccine and autism through a mechanism that involved a type of gastrointestinal disease. The study was small (only 12 children), did not include a control group, and the nature of the evidence was correlational without any evidence of causation. However, the study was picked up by the media and widely publicized. As a result of this vaccination rates against measles, mumps, and rubella began to drop due to parents being concerned about vaccines and autism. This led to an increase in cases of these diseases in children resulting in several deaths.
In 2004, investigations by a journalist revealed that Dr. Wakefield had perpetrated fraud by altering the facts of the patients’ medical histories for what appeared to be financial gain. Ten of the original authors of the paper retracted the interpretation of the findings making it clear that they had not found any causal association with the MMR vaccines and autism. Also in 2004, the journal carried out an investigation that absolved the researchers of the paper of charges of ethical misconduct that had been levied against them only to retract the paper 6 years later when additional investigations by the British General Medical Council found evidence of scientific misconduct. As a result of these investigations, Dr. Wakefield was removed from the United Kingdom’s Medical Registry and he now cannot practice medicine.
In response, Dr. Wakefield has claimed that he is being targeted by the medical establishment in collusion with vaccine manufacturing companies, and that he has never committed fraud. Wakefield has moved to the US where he has developed a following among anti-vaccination groups who consider him a hero. The whole autism/vaccine topic has become mired in endless controversy with one side accusing the other of ignoring scientific findings and the other side retorting that the truth is being manipulated by “the system”.
What is a concerned person to do about this issue? How do we determine who is right and who is wrong without getting bogged down in technical details?
The answer is: studies. Studies are the warp and woof of science. It is through studies that we determine the truth. But here is the thing; you need several of them. You can’t rely on just a couple, and you can’t quote selectively those studies that favor your pet theory. You also need the studies to have a large enough sample size. Small studies are notorious for producing erroneous results. Finally, some studies may be of greater quality than others. Therefore you need enough studies to accumulate so reviews of the studies can be performed (a study of studies if you will). This is normally a process that can take many years, but fortunately the issue of the MMR vaccine and autism has generated enough interest that many researchers have investigated it.
So what are the results?
An 2012 review as well as a more recent update of some of the best studies evaluating, among other things, any possible link between the MMR vaccine and autism reached the conclusion that there was no significant association between the two. These studies were conducted in many countries and, unlike Wakefield’s original study with 12 children, these studies all in all included hundreds to hundreds of thousands of children.
Are these negative results part of a vast international conspiracy of scientist who have sold out to some sort of evil conglomerate of pharmaceutical companies spanning the whole world?
Do you know about the “war” that scientists waged against the claims of the cigarette companies that smoking was not hazardous or that whether it was or not was not settled science when study after study demonstrated otherwise? Are you aware of the current struggle of scientists worldwide to counter the claims that there is no global warming when all evidence points in that direction? Why do we presume bad faith is involved on the part of all scientists that come to the conclusion that the MMR vaccine is not linked to autism? Do you think these scientists don’t vaccinate their children?
Let me explain something. The history of science is full of individuals that, like Wakefield, discovered something and had to fight to get their voice heard. But, unlike Wakefield, these individuals discovered something real that other scientists were able to duplicate in their studies and became convinced. Paradigms and ideas switch all the time in science. Just consider the proposals or discoveries of evolution, deep time, deep space, plate tectonics, the germ theory of disease, the deficiency theory of disease, relativity, DNA, prions and many others. Very few scientists would walk away from being associated with discovering a solid causative factor for autism. The truth is that the available data has convinced scientists that the link between the MMR vaccine and autism is nonexistent. Scientists have lost interest in this theory and they have moved on to explore what other factors can be responsible for autism, and this is an important and active area of research nowadays.
I understand that the autism issue can be a very emotional one, and it is really frustrating for parents to hear scientists say they don’t know what causes it. I also understand how in the midst of their despair many parents can be swayed by those who claim to have a simplistic answer along with an evil to fight against. If anything, the current political climate in the U.S. has demonstrated that this strategy works admirably well! However the best way to move forward is not to demonize scientists, but to join ranks with them and cooperate in finding the truth. This happens with many other diseases where families, clinicians, and scientists are actively involved in finding a cure and developing treatments.
The photograph by the US army is in the public domain.
In the late 19th century a series of remarkable discoveries in physics were made including X-rays and radioactivity. A new world of physical phenomena was being uncovered by scientists, and hopes of new discoveries were high. It was thus in 1903 that the French physicist Prosper-René Blondlot announced that he had discovered a new form of radiation which he christened N-rays after the University of Nancy where he worked. The problem was that N-rays were difficult to detect and several scientists had problems reproducing Blondlot’s experiments. So the British Journal Nature sent the physicist Robert Wood to Blondlot’s lab to witness an N-ray demonstration.
The demonstration involved an N-ray producing machine that relied on a prism made of aluminum to generate the rays. The room was darkened, the machine was started, and the N-ray measurements were begun. But Wood, who had a reputation as a debunker, removed the prism from the machine - something that would have caused the N-rays to cease to be produced. However, Blondlot and his assistant kept making the N-ray readings as if nothing had happened. This and other evidence led Wood to conclude that this radiation did not exist, and that what Blonlot was detecting was only present in his imagination.
The N-ray story is a classic example of experimenter bias. When a scientist is performing measurements that involve a subjective component, there is the danger that the scientist will see what he or she wants to see. The common solution to this problem is to make the scientist blind. Thankfully this does not involve gouging their eyes out, but rather coding the samples to be evaluated. In this way the experimenter is “blind” to the identity of the samples and thus the bias is eliminated. These blind protocols are routinely applied in science whenever there is a chance that knowing the identity of the samples will affect their reading.
But the complexity of the human mind to warp the scientific enterprise goes beyond the laboratory. In clinical trials a very well-known phenomena is the placebo effect. In this effect the patient experiences an improvement in their condition after being administered an inert substance or exposed to a procedure that should not be effective at treating their ailment. To avoid experimenter bias and the placebo effect, clinicians implement what is called a double blind protocol where both the doctor and the patient do not know the identity of the treatment.
Not controlling experimenter bias can lead to bad science. So, you see, the only good scientist is a blind scientist!
The image from Archive.org is in the public domain.