Are Vaccines Dangerous?
The State of the Data on Vaccine Safety and
its Relation to the Claims of the Anti-Vaccine Movement
The anti-vaccine movement has become increasingly influential across the United States in recent years, calling into question the safety and efficacy of vaccines and encouraging parents not to vaccinate their children because of the supposed harm being done by an exponential increase in infant vaccination schedules. Most alarming is the purported connection between vaccinations and the autism epidemic. However, things are not what they seem. While anti-vaccine advocates frequently speak of informed consent and increased transparency, they have themselves failed to provide accurate information and have painted a misleading picture about the transparency that already exists in the literature regarding the safety and efficacy of vaccines. I would encourage anyone interested in this issue to begin by reading Eula Biss’s book, On Immunity: An Inoculation. It is even-handed, insightful, well-researched, and engaging. She is not dismissive of the many unknowns that have led people to question the medical establishment on these issues, but sympathetically offers insights from the available research alongside broader discussions of how we go about addressing these public health issues. Alongside that book, which I will reference on occasion, I offer here a broad outline of the issues as they stand, along with links to some of the relevant literature.[1]
Vaccine Injury Statistics
In 2012, the Institute of Medicine, an independent non-profit research organization, published a 900-page study titled “Adverse Effects of Vaccines: Evidence and Causality.” A committee of eighteen independent medical experts worked without compensation for two years, examining 12,000 peer-reviewed studies of vaccination. The committee assessed 158 possible adverse effects of vaccination and found convincing evidence of only nine adverse effects, four of which were related to contracting chickenpox from the chickenpox vaccine. While anti-vaccine advocates frequently claim that studies are not being done on the safety of vaccines, the reality is that thousands of large-scale studies have been carried out on the possible adverse effects of available vaccines. As this study showed, there is no reason to be concerned about possible adverse effects of any of these vaccines, except for those listed as possible side effects when vaccines are administered.
By way of comparison, the question becomes: what are the sources of anti-vaccine claims about the dangers of vaccines? There are three primary ways that they come up with the claims that you will see throughout anti-vaccine literature. First, they rely heavily on anecdotal evidence. When a few patients who have received the same vaccinations appear to develop related symptoms, doctors rightly question whether there is a causal connection. However, as we know from countless studies, anecdotal evidence can be extremely misleading. Especially given the fact that, depending on the vaccine, sometimes over a billion people are receiving it. Inevitably, when that many people receive the same medical treatment, countless perceived correlations will pop up, which end up being explicable by other factors. A 2013 study showed 23 out of every 100,000 Americans aged between 75 and 84 had died from a variety of causes unrelated to the vaccine within a week of being inoculated—and these correlations invariably cause worry even though there was no causal connection. The only way we can know the cause is by doing studies, which time and again show that the perceived correlation is a red herring. Frequently, even when there have been large studies that failed to find any causal link, anti-vaccine advocates will claim no studies have been done, or simply dismiss their findings, because they do not match the conclusions that the anti-vaxxers have already come to.
Second, the anti-vaccine literature is crowded with instances of misreporting the conclusions of scientific studies. With shocking frequency (in fact, the vast majority of the time in what I’ve read), when anti-vaccine activists cite scientific studies, they simply lie about the conclusions, stating the opposite of what the study found, presumably counting on the fact that their audience won’t check. As one example of many, a well-known anti-vax doctor wrote what is now a widely repeated claim:
“Children vaccinated with the DPPT (diphtheria, pertussis, polio tetanus) vaccine or MMR (measles, mumps, rubella) vaccine had 14 times more asthma and 9.4 times more eczema than non-vaccinated children." (McKeever TM, Lewis SA, Smith C. “Does vaccination increase the risk of developing allergic disease? A birth cohort study,” Winter Abstract supplement to Thorax 57 (2002): Supplement III).”
And yet, McKeever, Lewis, and Smith actually wrote: “We conclude that the currently recommended routine vaccinations are not a risk factor for asthma or eczema.” By using a previously established birth cohort in the West Midlands General Practice research database, they found an association between vaccination and the development of allergic disease; “however, this association was present only among children with the fewest physician visits and can be explained by this factor.” While most of those who developed allergic disease had been vaccinated, only those vaccinated who also lacked access to medical care developed allergic disease, which points clearly to a cause other than vaccination. One finds countless instances of this kind of blatant falsehood peppered throughout anti-vaccine literature and videos. It is rare to come across accurate reports of what the scientific literature actually says.
At times, it is unclear whether the anti-vaccine activist are lying intentionally, or if they have simply misunderstood the studies. For example, the anti-vaccine activists frequently claim that vaccines interfere with transplacental (i.e., passive) immunity—that is, the antibodies passed from mother to baby. But the study they cite actually showed the opposite: that passive immunity may interfere with the efficacy of a specific vaccine.
Third, anti-vaccine literature often ignores the most important studies, and frequently claims that such studies do not exist. When anti-vaxxers do cite studies correctly, it is almost always initial studies with small sample sizes. These studies are typically written to flag a possible correlation between a specific vaccine and an adverse effect, and to call for a larger study to look into causation. In each instance I have come across, these initial articles were followed up by a massive controlled study that found no connection between the vaccine and the supposed adverse effect. But anti-vaxxers will cite the original article as if it was a conclusive study and pretend the later study does not exist. For example, it is frequently claimed that vaccines cause SIDS. The study they cite from 1982 was an initial short article that suggested a possible correlation after two infants died of SIDS a day after receiving the DPT immunization. A full study was undertaken by the National Institute of Childhood Health and Development that compared 800 infants who died of SIDS with 1,600 control infants. The study, which was published in 1987, concluded that “there is no suggestion of an excess of deaths due to SIDS following DPT immunization.” In the anti-vax literature, there is never a mention of the control study of 2,400 infants—they just cite the short article about the two infants.[3] In a similar case, Evee Clobes became (and remains) the face of the anti-vax movement when she died 36 hours after a checkup at which she received some vaccinations. An autopsy and investigation later determined that she had been suffocated by her mother while co-sleeping in the same bed.
If you are interested to know more about the people behind the anti-vaccine movement, I recommend Paul Offit’s book which tells the history of how the anti-vaccine movement started and developed alongside the history of the development and study of vaccines.
The numbers that get thrown around by anti-vaxxers about vaccine injuries are largely fabricated, which is why there is such a massive disparity between the fear exhibited by anti-vaxxers and the calm assurance of public health experts. The actual statistics about vaccine injury are quite striking. Only between 1 and 12 in a million people vaccinated is experiencing any significant injury (most frequently muscle tears from improperly inserted needles).[2]
Numbers based on claims through VICP. Table from https://www.snopes.com/fact-check/doj-most-dangerous-vaccine/
Compare that with drinking water: the CDC estimates that as many as 32 million people a year experience acute gastrointestinal illness from public drinking water systems in the U.S. That is almost 1 in 10. Or compare it to driving a car: 2.3 million people are hospitalized with injuries from motor vehicle accidents in the U.S. each year, which is just over 1 in 10 registered drivers. This means you are 100,000 times more likely to get seriously sick/injured from drinking water or driving a car than from being vaccinated. There are very few products, medical or otherwise, that can be given to over a billion people and not cause some kind of damage or accidental problems for a handful: almost anything can be dangerous to someone. In this light, vaccines are actually some of the safest products on the market. By way of contrast, the diseases we are vaccinating against would prove catastrophic in terms of injury and death if we did not immunize against them.
Here are a few examples from the CDC: Nearly everyone in the U.S. got measles before there was a vaccine, and hundreds died from it each year. Today, most doctors have never seen a case of measles. More than 15,000 Americans died from diphtheria in 1921, before there was a vaccine. Only two cases of diphtheria have been reported to CDC between 2004 and 2014. An epidemic of rubella (German measles) in 1964-65 infected 12½ million Americans, killed 2,000 babies, and caused 11,000 miscarriages. Since 2012, 15 cases of rubella were reported to CDC. After (ultimately unfounded) fears of the pertussis (whooping cough) vaccine led British parents to stop using it in the mid-1970s, an epidemic swept through Britain, hospitalizing more than a hundred thousand children and killing six hundred of them. In the prevaccine era, the US saw 115,000 to 270,000 cases of pertussis and 5,000 to 10,000 deaths due to the disease each year. Since then, there have been 1,200 to 4,000 cases and five to ten deaths per year. On the whole, it is estimated that 2 to 3 million lives are saved each year by vaccines.
The Rise in U.S. Rates of Autism
Recent decades have seen a relatively consistent rise in diagnoses of ASD (Autism Spectrum Disorder) in American children but talk of an ‘autism epidemic’ is not necessarily warranted by the data. It appears that the idea of such an epidemic originated from a 2002 California legislative report that suggested a 273% increase in autism from 1987 to 1998. Even if we ignore the various limitations of the report and take this number at face value,[3] the majority of this increase appears explicable by ascertainment factors:
(a) The exponential increase in our understanding of the disorder. For example, one of the most influential studies from the 1940s, by Hans Asperger, was not translated into English, and thus not widely known in the U.S., until 1990. Only with the development of psychology as a field of medicine in the mid-20th century did people begin to observe what later became known as autism, and they frequently diagnosed it as mental retardation and/or childhood schizophrenia. It has been a long process to come to see ASD as a distinct disorder, and with each gain in our knowledge has come a cascade of increased diagnoses. The author of one influential study from 1965 noted that after it was published, “Almost overnight, the country seemed to be populated by a multitude of autistic children.”
(b) Definitions and diagnostic criteria. The first edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), published in 1952, only mentioned autism once and included no diagnostic criteria. Criteria were added in subsequent editions in 1980, with a significant update in 1987. Subsequent editions in 1994 and 2013 each included significant revisions and added diagnostic criteria.
(c) Diagnostic tools. Zylstra et al. report that up through the 1980’s, children were being evaluated with generalized developmental screening tools focused on behaviors characteristic of a severe mental handicap, without differentiating between autistic and nonautistic children. After the publication of DSM III-R in 1987, developmental specialists were able to construct increasingly sensitive evaluation tools, with significant advances in 1994, 1999, and 2014.[4]
(d) Treatment options and advocacy. As officials and parents have advocated for improved treatment and earlier screening, the number of diagnoses has increased. As politicians and celebrities have worked to increase awareness, more and more parents have noticed early signs and sought out diagnosis and treatment. As an autism diagnosis has become more socially acceptable, it has at times replaced diagnoses of learning disability and mental retardation, a trend known as ‘diagnostic substitution.’ And children with a diagnosis now have access to significant resources and services they would not otherwise get, which increases incentive to pursue diagnosis.
Regular studies have been conducted to quantify the possible increase in ASD in the U.S., but it has remained extremely difficult to ascertain whether the numbers represent a true proportionate increase and to what extent the increase reflects those factors outlined above. A 2006 study by the CDC found that in 2002 an estimated 1 in 153 eight-year-olds had ASD, while in 2006 it was 1 in 110. But as recently as 2014, we have made significant advances in ASD diagnostic practices, and more and more parents, particularly from low-income, Hispanic, and vulnerable populations are beginning to seek diagnosis and treatment, which they largely avoided or lacked access to in the past.
Numerous studies have been undertaken to understand the causes of Autism, which have shown it to be closely linked to genetics. This is shown most clearly in studies involving twins: When one identical twin has autism, the chance that the second twin has autism is over ninety percent. However, when one fraternal twin has autism (a twin with non-identical genes), the chance that the second twin has autism is less than ten percent. Researchers have even identified some of the specific genes that cause autism. It is less likely that environmental factors play a significant role, though researchers have found that thalidomide (a sedative) and the rubella virus can both cause autism early in pregnancy. Some researchers have contended that greater use of food preservatives and greater exposure of young children to environmental toxins may be contributing factors.[5] Other potential factors include Autism comorbidity[6] and biology.[7] One of the most widespread theories early on was a connection with Thimerosal, a substance used in several childhood vaccines until 2001. However, there is no evidence that Thimerosal has ever hurt anyone (see full bibliography of studies on the safety of Thimerosal here). None of the studies found any link between Thimerosal and ASD, and at least one study documented an increase in autism after thimerosal had been discontinued.[8]
Similar claims, regarding autism and other developmental disorders, are also advanced with regard to aluminum adjuvants. While some vaccines do use small amounts of aluminum to stimulate an immune response, it is the third most abundant element on earth and it enters our bodies through air, food, and water, even through breastmilk and formula, in far higher quantities than in vaccines. The amount of aluminum contained in vaccines is similar to that found in 32 fluid ounces of infant formula. Aluminum has been found to be dangerous to humans under one condition: when one’s kidneys aren’t functioning and they receive large quantities of aluminum—quantities far greater than what is present in vaccines. Researchers have studied the quantity of aluminum in blood before and after vaccination and found no difference.[9]
The origin of the connection between the MMR vaccine and ASD is, of course, the fabricated research of the discredited Dr Andrew Wakefield. His article was retracted after no one was able to replicate his findings. Multiple independent reviews of his research concluded that “Clear evidence of falsification of data should now close the door on this damaging vaccine scare.” They later discovered that a lawyer who was putting together a lawsuit against a pharmaceutical company paid Wakefield £425,000 to fabricate his results. Beyond Wakefield’s fabricated research, arguments depend on the simple conflation of correlation with causation (the claim that if A came before B, then A caused B): children receive vaccines against more diseases now than they used to, and there are more children diagnosed with autism today than there used to be. Therefore, so they claim, one must have caused the other. To see why this is not necessarily the case, we need only consider other similar correlations. Here is an example from the WHO:
Without concrete evidence of causation, these correlations tell us nothing about the relative safety of vaccines or the causes of autism.
Instead of supporting anti-vaccine crusaders, who never mention the data outlined herein, those who are worried about the rise in ASD rates in the U.S. should be coordinating support for the research being done by the National Institute of Mental Health and the Interagency Autism Coordinating Committee. There are a number of advocacy groups for ASD, many of whom have publicly critiqued the anti-vax movement for standing in the way of progress toward understanding causation, diagnosis, and treatment. The anti-vax movement has also done much to stigmatize ASD, frequently speaking as if living with autism is worse than dying from smallpox. Fortunately, this is a false dilemma, but speaking this way goes a long way toward dehumanizing ASD children.
The fact is that massive research efforts are underway in relation to the genetic and environmental causes of autism.That effort is no longer focused on the connection with MMR because countless large studies have already been done, and none have ever shown a link. [10] A meta-analysis on over a million vaccinated and non-vaccinated children revealed no relationship between vaccination and ASD.[11] (For an extensive list of studies on ASD and vaccines, see autismsciencefoundation.org/what-is-autism/autism-and-vaccines/). Researchers have continually noted that there is likely no single cause of ASD, but a confluence of factors that result in varying levels of impact (hence, the ‘spectrum’ part of ASD). If we could redirect the tens of millions of dollars a year going to anti-vaxxers who simply spend their time scaring people on YouTube, and put that money toward actual research, we could make significant strides toward better understanding this difficult and complex public health crisis.
The Ramp-Up of the Vaccine Schedule
Even though children receive vaccines against significantly more diseases today than they did in the past, the design and manufacture of vaccines are much more precise, such that the number of antigens children receive today by age 4 is at least 25-fold fewer than it was 30-40 years ago. In fact, even at birth, a child is exposed to more antigens in their environment than in all their initial vaccinations combined. The total number of immunological components in all of a child’s vaccines is slightly less than 160, compared to the millions of pathogens we encounter every day by simply eating, breathing, and living our lives. And, as the CDC points out, their childhood immunization schedule, which is also recommended by the American Academy of Pediatrics and the American Academy of Family Physicians, is the only vaccination schedule that is rigorously tested for safety and effectiveness.[12] There is no evidence that today’s vaccine schedule has had any negative effect on infants, and in fact, all of the evidence points to it being even better for them than older vaccines. A large number of anti-vaccine crusaders, especially those who are MDs, sell alternative vaccination schedules that have not been tested for safety or efficacy. See studies here, here, here, and here.
Who Has Something to Gain?
Behind a lot of anti-vaccine arguments is the question of money: if pharmaceutical companies are making hundreds of millions of dollars on vaccines, why should we trust that they care about our well-being? By contrast, aren’t the anti-vaccine people just well-meaning doctors who are raising some red flags about a notoriously corrupt industry?
While pharmaceutical companies unquestionably have their problems, these claims are highly misleading. As Eula Biss notes in her book On Immunity, “Compared to other pharmaceuticals, vaccines are costly to develop and generate modest profits. ‘In 2008, Merck’s revenue from RotaTeq was $665 million. Meanwhile, a blockbuster drug like Pfizer’s Lipitor is a $12 billion-a-year business.’ Older vaccines make considerably less money than new vaccines, and vaccine production has not proved profitable enough to keep many companies from leaving the business over the past thirty years.” Many pharmaceutical companies have tried to get out of the vaccine game for this reason, and have been incentivized by the government to stay in it. With government support, vaccine profits have grown in recent years, so that the vaccine market now comprises 2 to 3 per cent of the pharmaceutical industry.
Furthermore, most of the studies into vaccine safety have been carried out by independent researchers who do not benefit financially from vaccine profits. So, while it is true that pharmaceutical companies make money off the sale of vaccines, they are not the only scientists who study vaccines, and there is little reason to think that they would willingly harm entire populations in order to generate the modest profits they afford. As Biss writes, “That so many of us find it entirely plausible that a vast network of researchers and health officials and doctors worldwide would willfully harm children for money is evidence of what capitalism is really taking from us … When we begin to see the pressures of capitalism as innate laws of human motivation, when we begin to believe that everyone is owned, then we are truly impoverished.”
By comparison, then, we might ask: why would anti-vaccine activists make this stuff up? I’m sure that the answers are as varied as the people involved. But there are two obvious elements that play an outsized role. The first answer is, actually, money. Prominent anti-vaccine activists make millions of dollars on ad revenue from their blogs and videos, and from selling books, videos, (untested) alternative vaccine schedules or alternatives to vaccines, hosting rallies and speaking at events, and so on.[13] Being anti-vax is big business, and anti-vax crusaders are hugely financially motivated to continue this narrative. This is part of a broader trend of conspiracy theorists making big money online. One prominent internet conspiracy theorist, made over $40 million on Youtube, Facebook, and Instagram in 2019 just from spreading misinformation online. In addition to the money, these people get to be treated like heroes and prophets: prescient whistleblowers fighting for the common man. That hero complex is immediately evident in how they present themselves in videos and at their rallies, and it is a powerful motivator for anti-vaxxers to ignore the evidence and stick to the script.
The second answer is ideology. The push for a radically individualistic approach to public health, the attempt to discredit experts, the desire to paint certain public figures as evil and implicate them in conspiracies: all of this matches up with certain social and political movements in the U.S., of which we are all well aware. One need not disagree with their politics to recognize that we can’t let those agendas drive our response to scientific questions. Unfortunately, viruses don’t care about our politics. Rather than fabricating problems with the safety and efficacy of vaccines in order to scare people into falling in line with a certain social and political agenda, we have to let our understanding of the safety and efficacy of vaccines be led by the scientific data. It’s not perfect, but it is the only concrete way for us to know the facts one way or the other. Once we have ascertained the actual safety and efficacy of vaccines, then the ethical and political arguments come in. Given the scientific facts about vaccine safety and efficacy, what approaches can we pursue as a society that are prudent and just? The fact is that the immunity of the whole is the only reliable means to the immunity of most individuals, including especially the vulnerable among us. This means that vaccines serve a common good and must be discussed in such terms.[14] No matter how much the libertarians among us might wish otherwise, universal collective action is our best bet against communicable disease.
All of this is not to say that just because someone is earning money on something, that proves they are wrong. Again, we don’t want to fall in the trap of seeing the pressures of capitalism as innate laws of human motivation. However, there is a big difference between someone earning money by doing work for which they have the relevant expertise, and someone earning money by selling untested products and advice for issues about which they do not have the relevant expertise. There is a pervasive perception that this conversation is a choice between trusting big evil greedy corporations vs. kind thoughtful individuals who only care about truth. But in reality, it is a choice between trusting modestly paid, highly trained researchers vs. highly paid undereducated bloggers and video personalities (some of whom are medical doctors, trained in applied medicine, almost none of whom are PhDs, trained in the relevant fields of medical research). Compared with the scientists publishing the relevant studies, anti-vaccine propagandists are making far more money. And while they often present themselves as practicing doctors who are concerned with public health, many of them are not practicing MDs: their full-time job is anti-vaccine crusading. Meanwhile, much of the research done on vaccine safety is carried out by independent academics who do not benefit financially from the sale of vaccines.
Homeopathic Alternatives
Many people who are wary of vaccines but recognize the importance of immunity against diseases have opted for ‘homeopathic’ or ‘natural’ vaccines. Homeopathic ‘vaccines’ take nosodes (“a remedy prepared from a pathological specimen consisting of saliva, pus, urine, blood, or diseased tissue”) and then dilute it down so much that there is essentially nothing left but water. In fact, many include on the bottle the following disclaimer: “There are no whole molecules of the actual substance in this potency.” The idea is that by exposing your immune system to tiny particles of a disease over time, you will eventually develop antibodies against it. But the reality is that, as Dr Mark Crislip notes, “There has to be something there, a real molecule of some sort, for the immune system to recognize and respond to. There is a threshold below which foreign material will not be recognized.” In 2018, a double-blind control study was done comparing immune responses in homeopathic, conventional, and placebo groups. They found that the homeopatic ‘vaccines’ did not elicit an immune response and that homeopathy had the same result as the placebo, whereas the conventional vaccines provided a robust antibody response. Not only are homeopathic remedies not tested for safety, there is also no evidence that they provide any protection against communicable disease.
Informed Consent
Anti-vaccine activists claim to champion ‘informed consent’, but they do not provide people with accurate information to aid their decisions, which means their real aim is misinformed consent. The data on vaccine safety and efficacy is quite straightforward, and it would not be difficult for parents to make knowledgeable decisions about vaccination, were it not for the amount of misinformation and disinformation in circulation. What these activists are actually asking parents to do is ignore the available evidence and rely instead on ideologically driven disinformation. As we’ve seen, they’re not providing real alternative data; they’re offering alternative theories and fabricating data to back it up. Those who decide not to vaccinate themselves or their children have been misled and scared into not trusting the evidence about this issue, and have been convinced to put outsized faith in the opinions of individual anti-vaccine doctors and propagandists instead. Deadly vaccine-preventable diseases are now on the rise in the US as a result of this movement, and the primary victims of those diseases are the children of well-meaning parents who couldn’t find their way through the gauntlet of disinformation anti-vaccine activists put in their way. If the anti-vax crusaders cared about the safety and efficacy of vaccines, then they would use their platforms to raise money for professional studies on vaccine safety and efficacy. Instead, they funnel all of that money into their own pockets, and use it to frighten people online.
Further Reading:
Eula Biss, On Immunity: An Innoculation (Graywolf Press, 2015)
Paul Offit, Deadly Choices: How the anti-Vaccine Movement Threatens Us All (Basic Books, 2010)
DeStefano et al., “Principal Controversies in Vaccine Safety in the United States”
Institute of Medicine, “Adverse Effects of Vaccines: Evidence and Causality”
The Children’s Hospital of Philadelphia list of Vaccine Websites
Respectful Insolence Blog: Regular updates responding to anti-vax claims
[1] I am a researcher in the humanities, and thus an amateur in this field, so what follows is not the opinion of a medical expert. Nonetheless, as a researcher I do have access to the relevant academic studies, some of which are hidden behind paywalls for the general public.
[2] Vaccine Injury Rates. Note: this is injury claims through VICP [Vaccine Injury Compensation Program]. That means that, while it is possible that more people are experiencing injury than are bringing claims to the VICP court, it is also possible that few of these were actually caused by the vaccine, because causation does not have to be proven in VICP. Also, those who bring claims to VICP receive free representation, so there is no reason not to bring a claim forward if you do experience injury and believe it was caused by a vaccine. The burden of proof is extremely low and they frequently pay out on the basis of very little evidence. For more on VICP, see their website <https://www.hrsa.gov/vaccine-compensation/index.html>. See also this discussion about why the court was set up and the numbers and amounts of claims: https://www.snopes.com/fact-check/doj-most-dangerous-vaccine/. This article outlines some stories from victims of the most common injuries claimed through VICP: https://www-sciencemag-org.ezp.lib.cam.ac.uk/news/2017/04/vaccines-trial-us-court-separates-fact-fiction#
[3] California Legislative Report on Autism. This report was restricted to California, so environmental factors could mean that it is not generalizable across the country. Furthermore, 14-fold variance rates between similar studies have been reported, which show just how difficult it is to establish reliable numbers (Fombonne E. Epidemiological trends in rates of autism. Mol Psychiatry. 2002;7 [suppl 2]: S4-S6).
[4] Autism Diagnostic Criteria. See, e.g., Lord C, Rutter M, Le Couteur A. “Autism Diagnostic Interview-Revised: A revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders”. J Autism Dev Disord. 1994;24:659-685.; Baron-Cohen S, Allen J, Gillberg C. “Can autism be detected at 18 months? The needle, the haystack, and the CHAT.” Br J Psychiatry. 1992;161:839-843; Robins DL, Fein D, Barton ML, et al. “The Modified Checklist for Autism in Toddlers: an initial study investigating the early detection of autism and pervasive developmental disorders.” J Autism Dev Disord. 2001;31:131-144; Ehlers S, Gilberg C, Wing L. “A screening questionnaire for Asperger syndrome and other high-functioning autism spectrum disorders in school age children.” J Autism Dev Disord. 1999;29:129-141.; Robins DL, Casagrande K, Barton M, et al. “Validation of the modified checklist for Autism in toddlers, revised with follow-up (M-CHAT-R/F).” Pediatrics. 2014;133:37-45.)
[5] Autism: Possible Contributing Environmental Factors. Landrigan P. “What causes autism? Exploring the environmental contribution.” Curr Opin Pediatr. 2010;22:219- 225. This study concluded that “the most powerful proof-of-concept evidence derives from studies specifically linking autism to exposures in early pregnancy - thalidomide, misoprostol, and valproic acid; maternal rubella infection; and the organophosphate insecticide, chlorpyrifos. There is no credible evidence that vaccines cause autism. Expanded research is needed into environmental causation of autism. Children today are surrounded by thousands of synthetic chemicals. Two hundred of them are neurotoxic in adult humans, and 1000 more in laboratory models. Yet fewer than 20% of high-volume chemicals have been tested for neurodevelopmental toxicity. I propose a targeted discovery strategy focused on suspect chemicals, which combines expanded toxicological screening, neurobiological research and prospective epidemiological studies.”
[6] Autism Comorbidity. “As autism is frequently comorbid with other developmental disabilities, advances in medical technology that have led to a decline in neonatal death and overall mortality among the disabled may mean more survivors are subsequently diagnosed with an autism comorbidity.” (Zylstra et al.)
[7] Autism: Biological Factors. Recent studies suggest that advanced paternal age can increase the risk of autism. (Flatscher-Bader T, Foldi CJ, Chong S, et al. “Increased de novo copy number variants in the offspring of older males.” Transl Psychiatry 2011;1:e34). Two studies suggest moderate genetic heritability, along with a substantial environmental contribution (Hallmayer J, Cleveland S, Torres A, et al. “Genetic heritability and shared environmental factors among twin pairs with autism.” Arch Gen Psychiatry 2011;68:1095-1102) And new research suggests that maternal stressors during pregnancy—e.g., trauma, illness, or substance abuse—may increase a child’s risk of developing autism, among other psychiatric disorders (Fine R, Zhang J, Stevens HE. “Prenatal stress and inhibitory neuron systems: implications for neuropsychiatric disorders” Mol Psychiatry. 2014 April 22).
[8] Thimerosal and Autism. Indeed, the most compelling numbers to substantiate a rise in ASD point to the increase happening after Thimerosal was removed. Price CS, Thompson WW, Goodson B, et al. “Prenatal and infant exposure to thimerosal from vaccines and immunoglobulins and risk of autism.” Pediatrics 2010;126:656-664; Fombonne E, Zakarian R, Bennett A, et al. “Pervasive developmental disorders in Montreal, Quebec, Canada: prevalence and links with immunizations.” Pediatrics 2006;118:e139-e150.
[9] Aluminum Adjuvants. https://www.who.int/vaccine_safety/GACVSsymposiumTrack1-Safety-issues-reviewed-during-early21st-century.pdf?ua=1. N. W. Baylor, W. Egan, and P. Richman, “Aluminum Salts in Vaccines—US Perspective,” Vaccine 20 (2002): S18-S23; N. J. Bishop, R. Morley, J. P. Day, and A. Lucas, “Aluminum Neurotoxicity in Preterm Infants Receiving Intravenous-Feeding Solutions,” New England Journal of Medicine 336 (1997): 1557-1561; Committee on Nutrition, “Aluminum Toxicity in Infants and Children,” Pediatrics 97 (1996): 413-416; P. O. Ganrot, “Metabolism and Possible Health Effects of Aluminum,” Environmental Health Perspectives 65 (1986): 363-441; L. S. Keith, D. E. Jones, and C. Chou, “Aluminum Toxicokinetics Regarding Infant Diet and Vaccinations,” Vaccine 20 (2002): S13-S17; J. A. Pennington, “Aluminum Content of Food and Diets,” Food Additives and Contaminants 5 (1987): 164-232; K. Simmer, A. Fudge, J. Teubner, and S. L. James, “Aluminum Concentrations in Infant Formula,” Journal of Paediatrics and Child Health 26 (1990): 9-11.
[10] MMR and Autism. Chen et al., 2004; Dales et al., 2001; Fombonne and Chakrabarti, 2001; Fombonne et al., 2006; Geier and Geier, 2004; Honda et al., 2005; Kaye et al., 2001; Makela et al., 2002; Mrozek-Budzyn and Kieltyka, 2008; Steffenburg et al., 2003; Takahashi et al., 2001, 2003; DeStefano et al., 2004; Richler et al., 2006; Schultz et al., 2008; Taylor et al., 2002; Uchiyama et al., 2007; Farrington et al., 2001; Madsen et al., 2002; Mrozek-Budzyn et al., 2010; Smeeth et al., 2004; Taylor et al., 1999. As the independent review of this literature by Stratton et al. concludes, “The authors concluded that administration of MMR or single-antigen measles vaccine is not associated with an increased risk of autism in children” (“Adverse Effects of Vaccines: Evidence and Causality” Institute of Medicine [2012], p. 148).
[11] Meta-analysis on vaccinated and unvaccinated children. They also found no relationship between MMR and ASD, thimerosal and ASD, or mercury and ASD. The case-control data found no evidence for increased risk of developing autism or ASD following MMR, Hg, or thimerosal exposure when grouped by condition or exposure type. The findings suggest that neither vaccination nor their components are associated with the development of autism. (Taylor LE, Swerdfeger AL, Eslick GD, “Vaccines are not associated with autism: an evidence-based meta-analysis of case-control and cohort studies.” Vaccine 2014 Jun 17;32(29):3623-9. doi: 10.1016/j.vaccine.2014.04.085. https://pubmed.ncbi.nlm.nih.gov/24814559/).
[12] Recommended Immunization Schedule. https://www.healthychildren.org/english/safety-prevention/immunizations/pages/default.aspx; https://www.aafp.org/patient-care/public-health/immunizations.html. See also discussions here https://www.vaccinateyourfamily.org/vaccine-safety/; here https://www.nbcnews.com/health/health-news/vaccines-don-t-overload-babies-immune-systems-study-finds-n854161; and here https://respectfulinsolence.com/2018/03/07/yet-more-evidence-that-the-antivaccine-trope-of-too-many-too-soon-is-nonsense/
[13] Anti-vaxxer Income. Based on reported earnings, I have found dozens of anti-vaxxers making over $1 million a year. See also, https://www.washingtonpost.com/investigations/2019/10/15/fdc01078-c29c-11e9-b5e4-54aa56d5b7ce_story.html. This is an area that would benefit from further investigative reporting.
[14] Vaccines and the common good. It is important to distinguish between individual, public, and common goods. Individual goods are those that I can both achieve and enjoy as an individual. To enjoy a glass of whiskey or a plate of fish and chips is to appreciate this kind of good. These goods may require incidental cooperation mediated by the market, but this cooperation will be primarily transactional. Public goods are those that I enjoy as an individual but only achieve through cooperation with others. Because we as individuals are not capable of providing roads, clean water, sewer systems, or law and order and national security, local and national governments intervene as a mechanism by which we cooperate (primarily through taxation) to achieve goods from which we each benefit individually. Common goods, finally, are those that I both achieve and enjoy through cooperation with others — goods that only accrue to me as a member of a certain group or participant in a certain activity. A choir is an excellent example of this. The good of each singer as a choral singer is only realised in and through their cooperation for the good of the whole. The same goes for families and workplaces: I only flourish as a husband or employee through the flourishing of my family or company. Thus, it is uniquely the case for common goods that the good of the whole is greater than that of any individual, insofar as the good of each individual member qua member is only realised in and through the good of the whole. See my discussion of how to go about making ethical decisions about the common good (and the dangers of conspiracy thinking) here: https://www.abc.net.au/religion/how-conspiracy-theories-undermine-the-common-good/12373294