Vaccinations save an estimated 2.5 million lives worldwide each and every year.
But a growing number of people are opting not to vaccinate themselves or their children—putting their lives, and the lives of others, at risk. Rates of X, Y, and Z are now on the rise.
What’s behind the growing trend of anti-vaccination? Why do people avoid vaccines that the scientific community has deemed effective and relatively safe?
There are five key reasons.
1. Those who know the least get the worst information
Many people turn to the internet first when they need medical information. Overall, this isn’t such a bad thing—one study found that sources turned up by an internet search offer correct information about 75 percent of the time for everyday, uncontroversial health questions[6,7].
But for vaccination-related searches, the first 100 results were accurate only half the time[6,7]. Accuracy was even worse for common search terms (e.g., “vaccination”) that someone who is less informed on the subject might use. To get the good information, you need to search for technical terms, like “immunization” or “MMR vaccine”[6-9].
2. Some people are less trusting
Some people are more receptive to anti-vaccination messages simply because of their personality. In particular, some people naturally mistrust conventional authority figures.
So when governments, large public health organizations, academic institutions, and pharmaceutical companies promote vaccines, they tend to be skeptical—and then turn to less conventional sources of information[10,11].
3. Some people fear contamination
Another personality trait that matters is sensitivity to disgust—essentially, how easily you are grossed out[11-13]. If you are disgusted by the idea of being poked or injected with a foreign substance, you’re going to think twice before getting vaccinated[13,14].
The irony is that vaccines prevent the spread of disease, and all the disgusting things that go with it. But those who are sensitive to disgust see vaccines themselves as more contaminating than the diseases they protect against[11,13].
4. We tend to inflate small risks
Vaccines can have serious side effects in rare cases. But when we hear there’s a 1-in-a-million chance of a severe allergic reaction to a vaccine, we don’t process this information in a cool, rational way.
Partly, this is because the brain can’t fully comprehend just how rare 1-in-a-million is. And partly it’s because we see emotionally vivid events—like having a severe allergic reaction—as being much more likely to happen than they actually are[17,18].
5. We’re wired to find connections and create stories
It’s no coincidence that many anti-vaccination beliefs are about the supposed connection between childhood immunization and developmental disabilities.
Conditions like autism often become apparent around the same age as children are being vaccinated. When a loved one is diagnosed with a medical condition, often our first reaction is to find some way to create a meaningful story to explain it[16,19]. And if our child is diagnosed with autism soon after getting a vaccine that carries “some risk of serious side-effects,” it’s natural to suspect that the vaccine had something to do with it.
But it doesn’t even have to be our child. When we hear about a child “developing” autism after getting vaccinated, this sticks in our mind. What doesn’t stick are all the times that children are vaccinated but do not develop any health conditions[16,20-23].
Interestingly, anti-vaccination sources take advantage of these tendencies. While pro-vaccination sources provide statistics describing the small risks, anti-vaccination sources tend to provide emotional stories that shine a bright light on those risks[8,16]. It’s easy to see how the anti-vaccination side could be more persuasive.
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