It’s time to stop trying to prove that autism and vaccines aren’t linked. Why? Because parents who believe in the link, and believe that Big Pharma is covering it up, have much more in common with Big Pharma than they think.

To clarify: I don’t mean that doctors who are interested in the technical aspects of vaccines should stop studying vaccines. And I don’t mean that lawmakers shouldn’t keep piling on the legal burdens for those who don’t vaccinate their kids. I mean that it’s time to stop organizing studies meant to convince anyone of the fact that vaccines don’t cause autism.


To begin with, as we’ve seen, there’s never going to be a better argument than a measles outbreak. The California bill banning personal or religious exemptions from vaccination for children attending public school got a lot of flak. People are concerned about whether the state is heading towards mandatory vaccination and the erosion of personal liberties. It’s a good academic discussion, but the point is moot. The bill was prompted by the measles outbreak at Disneyland, but the outbreak inspired more than just legislation. As soon as news of the outbreak got out, there was a run on measles vaccinations. People who had previously seemed to be anti-vax began insisting that they vaccinated their kids. This is what happens when there is real danger. If there’s ever an outbreak serious enough to prompt debate about mandatory vaccinations for everyone, unvaccinated people with unvaccinated kids will be beating down the doors of health clinics demanding vaccinations.

There’s also the fact that trying to convince people to vaccinate via scientific studies seems to tap into a deep vein of contrarianism. “The Backfire Effect,” as we’ve seen, isn’t limited to vaccines. It can pop up whenever a person’s beliefs are challenged. Conflicting information reinforces the belief rather than dispelling it. In a study done on vaccine skeptics, the effects went even further. Although people who read over a CDC statement dispelling some of the myths about the flu shot giving them the flu were less likely to fear the effects of the flu shot, they were also less likely to get the flu shot. It seems trying to argue with people is even more useless in changing their behavior than it is in changing their beliefs.


Mostly, though, there’s the fact that for every study showing no link between vaccines and autism, there are studies that show a link between vaccines and autism. Do a few searches on “link between vaccines and autism,” sometimes with a “no” attached and sometimes not, and you’ll get an arms race of results.

The studies listed are not the same quality. Some studies that show links between vaccines and autism are simply studies that show that environmental factors could have an impact on autism rates. And of course, there’s no real comparison between the infamous Wakefield study, which had eight participants and indicated a link, and a later Canadian study that had 27,000 participants and indicated no link. Still, you have a study? Anti-vaxxers have a study. You have 10? So do they. You have 45? No problem.

The reason the study/study arms race won’t work is, without knowing it, anti-vaccination advocates have picked up a trick from their most hated enemy—Big Pharma.We know about publication bias. Studies that show a result, any result at all, are more likely to get published than studies that show no result. For some time, the same thing would happen during the testing phase of any drug. If a drug didn’t show positive (or positive enough), results in a test, it was always possible to keep testing until the tests returned the result that a company wanted. There are legitimate reasons to repeat or modify a test, but repetition is also a way to make a drug look effective when it’s not. To put a stop to this, in 2007 Congress passed a law requiring drug companies to register every test of a medical drug or device, and to make the results available to the public.

Some physicians complain that unregistered tests are still being done, and that even when a company discloses all its test results, journals and articles (some sponsored by drug companies) will publicize tests that get good results and quietly let conflicting evidence languish out of sight. No one said drug companies are angelic.

But, in this case, political groups pull the same trick. It sounds reasonable to insist that everyone keep testing, keep testing, keep testing, until you realize that only one result is going to be acceptable. And if that result comes up, none of the other tests are going to matter.