The Truth About Vaccines

Our health depends on eliminating stigma and misinformation

InIn 2000, the United States declared a huge milestone: Measles had been eliminated from the U.S. population. This was a massive public health victory over a ridiculously contagious and potentially deadly disease, and it resulted largely from the development of the MMR (measles, mumps, and rubella) vaccine, which first became available in the 1960s.

What those celebrating health advocates could not have foreseen, though, was the impact a fraudulent article published in the Lancet medical journal a couple years earlier, in 1998, would eventually have on those public health strides in the coming decades. The article, written by Andrew Wakefield and 12 of his colleagues, linked the MMR vaccine with the development of autism in young children, but it was ethically compromised to an alarming degree. It exploited the public’s fear and lack of understanding about autism spectrum disorder (ASD) and played a key role in undermining decades of progress in fighting infectious diseases as well as further stigmatizing people with autism.

I used to be a teacher. For over four years, a big part of my job was to help my students sift through the abundance of information they have access to and make sense of it. Social media seems to create a “distancing” effect, where people’s lives and decisions become punchlines, and communication is often hostile. It’s easy to see someone posting about their decision not to vaccinate and think, “Well, good luck with that.” It’s an impulse I’m definitely not immune to, and in this age of communication via memes, it’s tempting to just post something like this and move on:

But as darkly funny as that meme is, it ultimately does nothing to convince staunch anti-vaxxers and vaccine-hesitant parents—some of whom, I’m realizing, are my former students—of the value and safety of vaccines. Memes simply can’t get to the heart of why people are so afraid of the perceived consequences of vaccinating.

BBack to Wakefield and company: Their article claimed to have uncovered a link between the MMR vaccine and autism, and it sparked a wave of panic about vaccinating children that ultimately led to the anti-vaccine movement we know today. Even prominent public figures like Robert F. Kennedy Jr. and former Green Party presidential candidate Jill Stein have expressed troubling sentiments about the safety of vaccines.

On the surface, this looks to vaccine skeptics like we have an article published in a peer-reviewed scientific journal of medicine, a member of one of America’s most well-known and respected political families, and a presidential candidate who used to be a doctor, all (implicitly or explicitly) questioning the safety and necessity of vaccines.

But let’s break down the original article by Wakefield and see why it’s actually so problematic. The Lancet issued a statement in 2004 in response to allegations of misconduct by Wakefield and his colleagues. The six main points were these:

  1. Certain invasive procedures used on the children in the study weren’t approved beforehand.
  2. The study itself hadn’t received proper ethics approval before it was underway.
  3. Wakefield and the other study co-authors handpicked which children would participate rather than using a randomized sample.
  4. The children in the study showed signs of autism before the study, and their parents were in the process of suing the MMR vaccine makers.
  5. Before the results were even reviewed or published, Wakefield sent them directly to the lawyers in that case.
  6. Those lawyers paid Wakefield 55,000 pounds (the equivalent of over $100,000 today) to conduct the study, which Wakefield didn’t disclose to the Lancet ahead of publication.

Beyond just being flawed and ethically compromised, the study bordered on maliciousness.

Then, in 2010, after scientists were repeatedly unable to replicate the study’s results and the General Medical Council found Wakefield guilty of ethical dishonesty, the Lancet retracted the original article in its entirety. (Online, it’s been clearly stamped with “retracted” in all caps.) Wakefield was stripped of his medical license because the results of the study were, to put it simply, bogus.

Beyond just being flawed and ethically compromised, the study bordered on maliciousness. Wakefield used the fact that autism was (and still is) a vastly misunderstood and feared disorder to his advantage, and the consequences of that exploitation have multiplied tremendously in the years since.

First, it created an atmosphere of intense fear and mistrust surrounding medical professionals and vaccines, meaning that fewer people were immunized against deadly diseases like measles. Second, it redirected funding for autism research away from productive studies and instead spent it on studies that tried and failed, time and again, to get the same results as Wakefield’s linking of vaccines and autism. Third, it perpetuated the fear and misunderstanding of people with autism, further stigmatizing them in society. As geneticist Jeanette Holden told the Canadian Medical Association Journal, “I think a lot of families were looking for a reason, so they were extremely vulnerable [to this explanation].” What’s more, the fear that vaccines might cause autism implies that autistic people’s very existence occasions blame rather than celebration.

AAlmost immediately after Wakefield and his colleagues published their article in 1998, vaccination rates went down. The same year that the findings were published, the rate of MMR vaccination of children aged 19 to 35 months in the U.S. dropped 2.5 percent from the previous year (from 88.5 percent to 86 percent). That number might seem small, but consider that the immunity threshold—the percentage of people who are immune to the disease and therefore can’t pass it to others—for measles is upward of 90 percent. Percentages below that leave a population vulnerable to spreading this potentially deadly disease.

More recently, we’re seeing clusters of measles outbreaks popping up in certain areas around the country. Although the rate of vaccination in the United States overall today remains around the 90 percent immunity threshold, pockets of the disease are appearing because like-minded people—including anti-vaxxers and vaccine-hesitant parents—tend to group together. Because of this, their population immunity is lower than that of the rest of the country as a whole, and they are more vulnerable to getting the diseases they aren’t protected against.

To make sure an illness like measles doesn’t spread like wildfire through a population, what’s needed is herd immunity. In the event a virus is introduced to a population, if enough people are made immune to the disease, then those who are unable to get vaccinated (due to age, allergy, or immunodeficiency from chemotherapy, HIV/AIDS, or other issues) will still be protected. In other words, you won’t be able to get a disease when the vast majority of people don’t have it. It’s important for everyone, then, that we get vaccinated. It’s up to those of us who are healthy enough to get vaccinated to protect those who are vulnerable. Even if a bout of measles may not kill you if you were to go unvaccinated, it could be deadly to the child with cancer sitting next to you at the doctor’s office.

Unfortunately, disease isn’t the only thing that spreads virulently in communities; misinformation also travels with alarming speed, particularly with unfettered access to the internet. Any person trying to do their due diligence to research vaccines may run across seemingly legitimate concerns that actually cherry-pick or decontextualize scientific information. Trusted groups like the World Health Organization and the Centers for Disease Control and Prevention, though, routinely refute those kinds of common misconceptions.

After removing the mercury-based ingredient in childhood vaccines, the rate of autism diagnosis did not decrease; it increased. One doesn’t cause the other—they just happen at similar ages.

For instance, the WHO notes the common claim that “the majority of people who get the disease have been vaccinated” is, in fact, true, but it’s taken out of context to imply that the vaccine itself is what causes the disease as an attempt to reinforce the idea that vaccines are unsafe. In actuality, though, two main circumstances are behind this phenomenon: 1.) No vaccine guarantees that 100 percent of recipients will be immune to the disease, and 2.) most people are vaccinated, which means the number of people for whom the vaccine is ineffective may still be higher than the number of unvaccinated people who get the disease, even though the percentage of vaccinated people who get sick is much lower.

Here’s a visual to help understand what’s happening. In this illustration, out of a total population of 100 people, 95 are vaccinated, and five are not (highlighted):

When the measles virus strikes, the red figures represent those who actually get sick—the five who weren’t vaccinated plus 10 others:

In this case, 10 of the 95 vaccinated people, about 11 percent of them, got sick, while 100 percent of the people who were unvaccinated got the disease. Even though more vaccinated people got sick in total, the percent of vaccinated people with measles was far lower than the percent of unvaccinated people with measles.

AAnother concern people often bring up about vaccines is that they contain a mercury-based ingredient called thimerosal. The fear is that this ingredient links vaccines to autism through mercury poisoning. There is, again, a surface-level logic—to a layperson, it’s easy to think of this as being injected with mercury, but that isn’t really the case.

There are multiple types of mercury, but the two most relevant to the vaccine discussion are methylmercury and ethylmercury. Methylmercury (MeHg) can be poisonous even in small amounts whereas ethylmercury (EtHg) is much safer. It is ethylmercury (EtHg) that is in vaccines.

Methylmercury (MeHg) has a chemical structure that is very similar to an amino acid called methionine. This means that it binds strongly to proteins in your body’s cells that carry cysteine, another amino acid fundamental to the structure of DNA. Because MeHg can bind so strongly with those proteins in your cells, it can travel easily throughout your entire body, even crossing the blood-brain barrier. That gives it access to your usually very well-protected central nervous system (i.e., your brain and spinal cord), where it can wreak all sorts of havoc. In some cases, it can cause a buildup of ions in the brain, which may lead to cell death. In other cases, it can cause your immune system to attack your own nervous system, leading to a process called demyelination, which is when the protective covering around your neurons (myelin) breaks down, and the electrical impulses being sent through them get disrupted. (It’s like a short circuit, and your brain has a harder time communicating with the rest of your body.) MeHg takes a long time, about 50 days, to fully metabolize out of your system, which gives it plenty of opportunity to build up, hang around, and do some real damage. Obviously, this type of mercury can have disastrous effects on any organism’s health, and humans are most likely to be exposed to it through foods. (This is, for example, why pregnant women are not supposed to eat fish.)

When tribalism seeps into public health discourse, we end up alienating ourselves from the solutions we all need to survive.

Ethylmercury (EtHg), however, has a completely different structure than MeHg. Although not as much is known about how the body metabolizes EtHg compared with MeHg—largely because for so many years researchers saw them as interchangeable—it is increasingly evident that the body metabolizes EtHg much more quickly than MeHg. It tends to stay in the system for about one-fifth the amount of time that MeHg does, meaning that it does not bioaccumulate, a fancy way of saying that it doesn’t build up and harm the system. The body processes EtHg so much more efficiently that it’s eliminated from your system as a waste product almost as soon as it’s put in, particularly if you don’t have prolonged exposure to it. Certainly, I’m not encouraging you to go out and chug a thermos of EtHg, but as with almost everything, the amount matters, and the amount of EtHg in thimerosal has been deemed harmless.

If you’re wondering why we have had thimerosal in our vaccines at all if it’s so controversial, the reason is simple: It’s a preservative. It keeps vaccines in multidose vials from being contaminated by harmful bacteria or fungi each time a new needle enters the vial. For childhood vaccines, thimerosal has actually been removed altogether, simply to avoid exposure to mercury of any sort in children, no matter how unlikely it is to be harmful. In these cases, the vaccines are not kept in multidose vials that might require a preservative; children’s vaccines are kept in single-dose vials that are used once and then discarded.

But here’s the kicker: If thimerosal actually were linked to the development of autism in children, we would expect to see the rates of autism decrease once we removed thimerosal from vaccines, right? That’s not the case. Children’s vaccines were no longer manufactured with thimerosal as of 2001, and the last ones containing it expired in January 2003. According to the CDC, “In the United States and other countries, the number of children diagnosed with autism has not gone down since thimerosal was removed from vaccines.” Thimerosal, then, seems to have no effect on the development of autism.

Yet we do have many kids developing autism around the time they get their shots. Doctors recommend children receive the MMR vaccine around 12-15 months of age, and it is around 18 months of age that the earliest signs of autism (such as late talking or regression of budding skills) can reliably be detected and diagnosed. I understand the urge to associate the two here; it is human instinct to link two things that occur so close together. But remember, after removing the mercury-based ingredient in childhood vaccines, the rate of autism diagnosis did not decrease; it increased. One doesn’t cause the other—they just happen at similar ages.

In fact, according to Dr. Stephen Camarata of Vanderbilt University, we should probably expect the reported autism rate to continue to increase in the coming years:

It is easy to predict that the [autism] rate will then double [in 2020] or perhaps even more because as many as 1 in 10 children talk late, as compared to the current autism data indicating a rate of 1 in 59. And, as mentioned earlier, because nearly all two year olds display some “symptoms” of autism it is likely that at least some of these children will be mistakenly included in the autism data—and raise rates astronomically.

Because of the possible overdiagnosis of children with general developmental delays rather than ASD and decreases in infant mortality rates—meaning that more children are living to the age when they could be diagnosed with autism—there is, right now, a steep upward trend in the rate of autism diagnosis. We have to keep in mind, though, that this spike in autism diagnoses doesn’t actually mean anything nefarious. Instead, it’s showing us that we now have improved health outcomes for infants and that we are getting better at identifying autism early.

AAll of this dances around another major issue at play: The public fear of autism is so potent that Wakefield successfully exploited it to turn thousands of people against accepting lifesaving preventive medicine. If our public knowledge about vaccines is weak, our understanding of ASD is atrocious. And because of its complexity, researchers have difficulty isolating what factors cause it. The current understanding of autism’s origins boils down to a combination of genetic and environmental factors that interact to influence the way a child develops.

That ambiguity alone, though, doesn’t seem to account for the intense societal stigma surrounding ASD. Fortunately, courageous people like Temple Grandin have shared their experiences of living and thriving with autism. Developmental disorders in general have gotten more representation in recent years, with works such as Out of My Mind by Sharon Draper, portraying the inner life of a perceptive, nonverbal young girl with cerebral palsy. Stories like these and others that have built a veritable community have the ability to bring ASD and other developmental disabilities into the social consciousness in a richly nuanced way that can help dispel the fear and aversion associated with them.

Ultimately, this issue comes down to communication and awareness. The vaccine issue has become polarizing and political, which leads to reductive and simplistic arguments. The victims of this rhetoric are the children who grow up unvaccinated and susceptible and the children with autism who grow up under the weight of stigma and misunderstanding. When tribalism seeps into public health discourse, we end up alienating ourselves from the solutions we all need to survive. There should be no shame in being wary or cautious nor should there be any in doing research and asking questions. In the end, we should not strive just to be right but to be informed.

So please, ask questions. And please vaccinate your kids.

Interested in lots of things, and trying to learn how to accomplish them.

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