Thursday, May 9, 2013

Herd immunities -- a Carbon Based original

    Climate scientists suffer through repeated abuse by fossil fuel shills and other denialists.  But climate scientists are not the only pariahs. Denial crops up almost everywhere a country tries to base its policies on sound scientific theories.  Vaccination is an infuriating example.

    Vaccinate enough people against a contagious disease and the whole population enjoys immunity, even those who shunned the needle.  A herd thus protected contains fewer potential paths to contagion and the disease cannot spread as easily. 

    A large goal in public health is to strengthen herd immunity. A population can withstand a disease far better when the numbers of the unvaccinated are low.  Thus for decades various childhood diseases have faded into medical history.

    Until recently. 

    Anti-vaccinationists blame the measles-mumps-rubella vaccine for a supposed surge in autism.  They say that the cost of protecting against the childhood diseases is too high, that its dangers are downplayed so that pharmaceutical companies and others can flourish at the expense of their victims. The theory is that the mercury in the thimerosol-based vaccine has neurotoxicity.   Only it doesn't.  At great expense, the theory has been persistently refuted by large epidemiological studies.  Andrew Wakefield, the leading proponent of this theory, has been exposed and debunked many times, but is still a leading figure among the anti-vaxxers.

    Much as with climate change denial, the patient explanation of the facts about vaccines does little to change the minds of the zealots.   Like climate change denialists, the antivaccinationists cultivate the appearance of scientific reasoning while bypassing the content.   They refuse to accept any evidence of the safety and effectiveness of vaccines. For example, elbow wagging explainers among the anti-vax crowd are at some pains to deny the existence of herd immunity.

    If thousands of people believe in astrology, it's unfortunate and laughable, but the harm is small. At least, I hope it is!  Not so with public health. Thanks to the work of celebrity anti-vaccinationists, an entirely avoidable public health emergency is at hand.  Measles, for example, has returned in Wales, in India, in Michigan, along with more cases of Down Syndrome.  

    A long-won battle is in danger of being lost because a large number of people don't believe in science.  Similar reality distortion goes on in discussions of climate change, when scientists tell people what they don't want to hear, and a surge of denial follows.

    Some herd immunities protect against disease.  Others protect against ignorance.  When ignorance is the risk, education is the vaccine.  That's the optimistic version, because ignorance can yield to knowledge at least some of the time.

    Like a disease, ignorance can kill or injure, wreaking long-lasting damage in many fields.  But the damage dwindles if ignorant people are mixed among a population of the better informed.  If enough people behave responsibly, the benighted can shun the vaccine and the public health damage won't be too great.  But this willfully ignorant group is always too large.  This is especially true of climate change.

    In matters of climate change policy, herd immunity requires widespread public knowledge of science.  If enough people pay enough attention to scientific matters, they improve their chances of making sound policy decisions. The protection is not perfect, and their scientific understanding may be flawed or full of holes.   But if they've taken steps to overcome their ignorance, then there's a better chance of enacting sound policies, and changing course when mistakes appear.

    The climate change debate, similar to the vaccination debate, hinges on the true cost of externalities -- not just the upfront economic cost of producing the energy, but the long-range ecological and risk costs as well.   The irony in the climate change debate is that the market mechanisms that could start to price in these long-range costs is exactly what the denialists abhor.  Their free market faith leads them to reject market mechanisms that might actually work.  They give capitalism a bad name.

    Of course, more than ignorance blocks acceptance of climate change action. There are the large minority of people who profit from greenhouse gas emissions, and their short-term interests trump everything. They may be well enough informed scientifically, but ideology and self-interest trump the science.  Ignorance and self-interest are overwhelming allies. 

    In climate change, a third of Americans reject any attempt to rein in free markets, which so far has been enough to stymie meaningful global action on climate.  The free market ideology, lovingly stoked for decades by a rightwing press, has resulted in toxic policy debate in which measures that are known to work can never be mentioned.

    The costs will be crushing.  Climate economist Nicholas Stern has estimate that climate change will cost about 5 percent of global GDP each year from here on out.

    So science education matters, but it's not a sufficient condition for progress.  Every high school in America could teach a sound course on climate change, and public opinion would not budge, I fear. We have a terrible example of what can happen with the teaching of evolution.  Once the deinal is mobilized, it's almost impossible to eradicate.   

    Some herds appear determined to hurt themselves.  They expose everyone to risks, whether out of ignorance or short-term self interest.  We keep coming back to the sour cosmic observation that Albert Einstein made: "Stupidity is stronger than genius because there is so much more of it."

Photo by Brian Thomas, public domain


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