Wednesday, August 14, 2013

The difference between rate and quantity

One of the strengths of science-based medicine is that it can look at large numbers and learn from trends. I find myself frequently frustrated in conversations about vaccines and homebirth by the inability of many to recognize that no matter how many people they know who have had an adverse reaction to a vaccine or had a poor outcome at a hospital birth, they don't have a good handle on the relative safety of forgoing vaccines or choosing homebirth unless they look at the overall rates of negative events.

Rates are what should be looked at when deciding risk. Certain diseases used to kill a high percentage of people, especially children; now that we've mostly gotten rid of those diseases in the developed world, it's understandable to also want to eliminate the risk posed by vaccines (which is real, though quite small). But if you forgo a vaccine, you merely exchange one risk--that of vaccine side effects--for another--that of getting the disease. Which risk is greater? That's the real question, and it calls for an individual answer by each family. If a person is always going to be hanging out in the developed world with people who are never carriers of a communicable disease, than they don't really need vaccines. I want to see the wider world and take my children with me, but I don't expect everyone to make the same choices I do. Homeschoolers tend to interact less with the general public, and given their specific situations, the risk of vaccination to some families might outweigh that of contracting the disease. They should realize, though, that all it takes is one child in their circle of like-minded friends to have been infected at a potluck by a dish prepared by a recent traveler carrying polio, and an outbreak could happen with very sad results. On the subject of homebirth, I already discussed in a prior post that evidence out of Oregon and Colorado shows that homebirth as presently practiced in those states increases the rate of neonatal fetal demise by at least 2-3 times, so I won't discuss it more here.

Many in the homeschool community embrace holistic/alternative/complementary medicine. It's no surprise; we are people used to bucking authority. The placebo effect is real and well-documented, and I don't doubt that some people find real benefit in utilizing CAM (complementary and alternative medicine). In general, alternative medicine does no harm as long as it doesn't lead people to turn away from needed medical measures that would serve them even better than a placebo. Too many, though, who dispense anti-medical-establishment advice spread false information to bolster the alternative medicine they embrace. I have seen a promoter of essential oils claim on their website that the tetanus vaccine does no good if given after a puncture wound, conveying a completely wrong description of how tetanus attacks. What if someone believes that, doesn't get the tetanus shot for an injured child, and the child ends up with tetanus? That's risking an 11% fatality rate from a mostly preventable illness.

Today (the reason for this post) I saw someone on Facebook tell several other homeschoolers that the chicken pox vaccine causes more fatalities than chicken pox. I pointed out that a hundred people a year used to die from chicken pox and asked whether there are more fatalities than that from the chicken pox vaccine, and she had no answer to it. (I did my own brief search and found no reported fatalities from the chicken pox vaccine.) She instead linked to an unsubstantiated anti-vaccine article by an author of CAM books, and then the FB conversation turned into "the CDC is government so it is untrustworthy, some doctors told me I'm doing the right thing, we are open to education and enlightenment but let's stop talking about this now before feelings get hurt, etc." Whose feelings? Theirs? I ask for proof, and they give me answers that sound like conspiracy theories. If they feel good about avoiding vaccines for their children, that is their choice. I can understand it without agreeing or making the same choice myself. But they shouldn't spread false information to feel even more confident about the different risks that they have chosen.

Americans need better education in math and statistics, be it delivered in or out of a school building. While I'm wishing, perhaps a little more epidemiology, too.

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