Morton's Demon - a hypothetical creature that a scientist named Glenn R. Morton described as an illustration of the power of confirmation bias - is like a disease. I believe the only reason it is not considered a disorder is because it is so widespread that it is considered a normal hazard of living. The true danger of living with Morton's Demon is its contagion: once a false idea takes root, it is nearly impossible to change.
Andrew Wakefield fabricated test results for money and fame, and for a while, people believed him. When Wakefield was exposed as a fraud, the newspapers that had proclaimed in large, friendly letters on their front pages that "vaccines cause autism!" published retractions in print too small to read on page 31C, if at all. As the body of evidence against Wakefield's lies builds up, the people who refuse to believe differently get shriller and shriller, and they are spreading the demon even further, and more and more people are dying from diseases that eleven years ago were close to being eradicated.
Now that Oprah Winfrey has given Jenny McCarthy, a Playboy model who became one such "concerned parent" after her son was diagnosed as autistic, an even larger platform from which to spew material for the demons, I wonder how much lower vaccination rates will go. I wonder how many children will have to die for McCarthy to realize how many people she has helped to kill.
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Morton's demon is just as strong on the other side. There are large groups that believe that all vaccines are inherently beneficial, regardless of the risks or benefits. There is no purpose in vaccinating against malaria in countries where malaria is not prevalent.
Vaccines for bacterial diseases tend to not always be effective, but for certain people, the benefits outweigh the risks. This is why the meningitis vaccine is not commonly used for children, but often given to college students: living in a dormitory is a risk factor for meningococcal meningitis.
Rabies is another vaccine whose risks obviously outweigh the benefits of giving it to the general public. Veterinarians should be vaccinated, of course, as well as anyone whose job exposes them to rabies. In most cases, the vaccine would be painful, dangerous and useless. In the case of a person who has just been bitten by a strange dog, the vaccine could be a lifesaver.
Nobody vaccinates against smallpox anymore because the smallpox vaccine worked. Of course the risk of vaccinating against a disease that exists in two heavily guarded labs outweighs the benefit.
The people who advocate vaccines for everything to be distributed to everyone concede these points easily enough. The problem is that they advocate a one-size-fits-all schedule, when one size clearly does not fit all. Too much strain on the immune system is harmful. The ideal, as it is with introducing solid food to babies, is one vaccine at a time. Not only does it allow the immune system to do its job most effectively, but it helps to narrow down the cause of any adverse reactions.
The anti-vaccine camp has made one or two good points. It is a shame that we have lost those points by disregarding everything they say.
Vaccines work. They are perhaps the greatest invention in public health. But they are not perfect, and we need to constantly strive to improve them. It is the best way to make the leechers who depend on herd immunity see reason.
(Images courtesy birdfarm and xkcd, made available through Creative Commons licenses)
