Public Health and Self-Interest
One thing I have learned as an anthropologist: the world is not nearly so simple as we often seem to think.
The topic of infant vaccinations and autism has cropped up on one of the blogs I follow. (There is an association between the administration of vaccines and diagnosis of autism. The causal relationship remains unclear, because vaccinations are administered at around the same age that autism begins to manifest.) The suggestion is that vaccinations should be embargoed unless and until it is clear that they do not cause autism — although that blogger, at least, shows enough sense to distinguish (even if only implicitly) between the effective ingredient and the suspect preservative, thimerosol (a mercury compound). Still, the argument is that when you're playing with "children's lives," you shouldn't wait until there's actual proof to halt the program.
[Big disclaimer: I don't know the actual numbers underlying what I'm about to say. I ran across them some time ago, I don't remember where, and there are other things I'd rather do than track them down. Still, I think they are in the ballpark.]
Apparently, the documented incidence of autism has increased more than 10-fold in the past couple decades. This reinforces the belief of a causal relationship between autism and vaccinations. But there are several other things that need to be considered in this connection.
The major vaccinations (at least in the U.S.) are for measles, mumps, rubella, diphtheria, whooping cough, tetanus, tuberculosis, polio, and chicken pox. Until it was more-or-less eradicated, smallpox was another biggie. Many of these can be deadly: measles, tetanus, TB, and polio for sure. As a result of these things,
The topic of infant vaccinations and autism has cropped up on one of the blogs I follow. (There is an association between the administration of vaccines and diagnosis of autism. The causal relationship remains unclear, because vaccinations are administered at around the same age that autism begins to manifest.) The suggestion is that vaccinations should be embargoed unless and until it is clear that they do not cause autism — although that blogger, at least, shows enough sense to distinguish (even if only implicitly) between the effective ingredient and the suspect preservative, thimerosol (a mercury compound). Still, the argument is that when you're playing with "children's lives," you shouldn't wait until there's actual proof to halt the program.
[Big disclaimer: I don't know the actual numbers underlying what I'm about to say. I ran across them some time ago, I don't remember where, and there are other things I'd rather do than track them down. Still, I think they are in the ballpark.]
Apparently, the documented incidence of autism has increased more than 10-fold in the past couple decades. This reinforces the belief of a causal relationship between autism and vaccinations. But there are several other things that need to be considered in this connection.
The major vaccinations (at least in the U.S.) are for measles, mumps, rubella, diphtheria, whooping cough, tetanus, tuberculosis, polio, and chicken pox. Until it was more-or-less eradicated, smallpox was another biggie. Many of these can be deadly: measles, tetanus, TB, and polio for sure. As a result of these things,
- once-common serious childhood ailments don't occupy doctors' attention so much any more
- doctors can pay more attention to once-less-pressing conditions
- with reduced child mortality from those illnesses, perhaps more children are surviving to manifest autism who otherwise might not have
So it is unclear to me that the association between increased incidence of autism and vaccinations is anything more than an artifact of vaccinations' success (in which case halting them would be a major irony).
But let's play devil's advocate and say that the association actually is causal. I don't know for sure, but I doubt autism kills. Even if it does, I doubt it's nearly as deadly as the others. AND, it's not transmissible: you can't "catch" autism from someone who has it. To then say that we're playing with children's lives is hyperbole (quality of life, yes. Life itself, no). In fact, to deprive children of immunity to potentially fatal illnesses that were once endemic is playing with their lives far more seriously.
I expect the argument to be made that many parents don't vaccinate their kids, and these diseases haven't regained their former incidence. But "many" parents is only in an absolute sense: with a few million children born every year, even a few thousands who aren't vaccinated is proportionally still very few. In other words, the relatively few unvaccinated children are being protected by the immunity of the vastly more common vaccinated children, because the unvaccinated population is still too small to sustain an epidemic.
But there is a threshold, and it's a lot lower than you might think [this is where my numbers become fuzzy]. I think it's somewhere between 10% and 30% of the population that needs to be susceptible in order to sustain an endemic — not that all 10–30% would contract the disease, but that if 10–30% of children are unvaccinated, then the protection they formerly had from the much larger vaccinated population vanishes, and the diseases return to their pre-vaccination incidence within the unvaccinated population. The incidence of autism may be 1 in 166 — but if these diseases occur with a cumulative 5% frequency within the susceptible population, and the threshold population is 10% of the total, that's an incidence of 1 in 200. AND, some of those children would die. (The incidence would, of course, be greater if the threshold is higher, even though a higher threshold would take longer to reach.)
Yes, it sucks if it's your kid that develops autism. But it sucks more if it's your kid that dies. And even if they don't kill, these diseases can cripple. Not to vaccinate one's children is to exploit a safety net that only exists because so many other parents vaccinate theirs; but if enough parents do the same, that safety net vanishes, and then the unvaccinated kids really suffer.
All of that said, the continued use of thimerosol does leave me wondering. Suppose that is a causal connection between vaccinations and autism. My contact-lens soaking solution makes a big deal of being "thimerosol free!" I buy it in big bottles that take months to use up – surely longer than it takes to use up a batch of vaccine? – and even then there's usually time to spare before the expiration date. It certainly seems like it should be possible to have thimerosol-free vaccinations. And even if that doubled the cost of the vaccinations, wouldn't that be worth going from a 1:166 chance of autism back to 1:2,000?
But let's play devil's advocate and say that the association actually is causal. I don't know for sure, but I doubt autism kills. Even if it does, I doubt it's nearly as deadly as the others. AND, it's not transmissible: you can't "catch" autism from someone who has it. To then say that we're playing with children's lives is hyperbole (quality of life, yes. Life itself, no). In fact, to deprive children of immunity to potentially fatal illnesses that were once endemic is playing with their lives far more seriously.
I expect the argument to be made that many parents don't vaccinate their kids, and these diseases haven't regained their former incidence. But "many" parents is only in an absolute sense: with a few million children born every year, even a few thousands who aren't vaccinated is proportionally still very few. In other words, the relatively few unvaccinated children are being protected by the immunity of the vastly more common vaccinated children, because the unvaccinated population is still too small to sustain an epidemic.
But there is a threshold, and it's a lot lower than you might think [this is where my numbers become fuzzy]. I think it's somewhere between 10% and 30% of the population that needs to be susceptible in order to sustain an endemic — not that all 10–30% would contract the disease, but that if 10–30% of children are unvaccinated, then the protection they formerly had from the much larger vaccinated population vanishes, and the diseases return to their pre-vaccination incidence within the unvaccinated population. The incidence of autism may be 1 in 166 — but if these diseases occur with a cumulative 5% frequency within the susceptible population, and the threshold population is 10% of the total, that's an incidence of 1 in 200. AND, some of those children would die. (The incidence would, of course, be greater if the threshold is higher, even though a higher threshold would take longer to reach.)
Yes, it sucks if it's your kid that develops autism. But it sucks more if it's your kid that dies. And even if they don't kill, these diseases can cripple. Not to vaccinate one's children is to exploit a safety net that only exists because so many other parents vaccinate theirs; but if enough parents do the same, that safety net vanishes, and then the unvaccinated kids really suffer.
All of that said, the continued use of thimerosol does leave me wondering. Suppose that is a causal connection between vaccinations and autism. My contact-lens soaking solution makes a big deal of being "thimerosol free!" I buy it in big bottles that take months to use up – surely longer than it takes to use up a batch of vaccine? – and even then there's usually time to spare before the expiration date. It certainly seems like it should be possible to have thimerosol-free vaccinations. And even if that doubled the cost of the vaccinations, wouldn't that be worth going from a 1:166 chance of autism back to 1:2,000?
posted by Dr. Bubbles at 11:15
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