Friday, March 21, 2014

A metaphor for the anti-vaccination crowd

I'm perpetually amazed that we still have to discuss this, but the anti-vaccination movement still hasn't faded into deserved obscurity. For example, the keynote speaker for this year's National Science Teachers Association conference is Dr. Mayim Bialik - you probably know her as an actress on Big Bang Theory - who, despite a neuroscience degree, has not vaccinated her kids. She gave a very non-committal answer to a question from Ira Flatow about vaccination, arguing that it's just a personal choice for each family.

Of course, that's simply not true, if you understand epidemiology. Take, as an example, the fact that outbreaks of whooping cough (pertussis) are geographically connected to places where higher numbers of parents opt out of giving their kids the vaccine for non-medical reasons. In other words, everybody is put at higher risk of getting whooping cough in places where parents don't vaccinate, even in a state with a 91% average rate of vaccination for kindergartners. And yes, it's the unvaccinated who are at most risk, leading to the remarkable result that "with vaccine-preventable infectious diseases, the risk is higher for those higher in socioeconomic status" (Dr. Kenneth Bromberg, director of The Vaccine Research Center). After all, it's those with time on their hands who have the luxury of delving into the kinds of conspiracy theories that fuel the pseudoscience of the anti-vaccination movement. Yet the neighbors of those who do not vaccinate are put at higher risk, as are the kids who go to school with unvaccinated children, their infant siblings and grandparents, and anybody who has a compromised immune system who comes into contact with the unvaccinated kids. The primary risk is personal, but secondary risk to the community is really significant.

Yet even with all the data that show the effectiveness of vaccines (heck, the field tests of the Salk polio vaccine lay the groundwork for modern double-blind clinical trials) a public figure with a science doctorate can somehow remain equivocal and see it as a matter of personal freedom. So here's a simple analogy that may help readers understand why the rest of us don't just say "OK, don't vaccinate your kids."

If you drive at night, you can turn on the headlights (and taillights) of your car to be more visible and decrease the chances of your having a collision. "But headlights consume energy and reduce my gas mileage," you might argue. "I wonder if it's a conspiracy of the oil companies to make me consume more fuel and pad out their profits." Um, sure. "In any case, it's a personal choice. I should be able to drive at night without my headlights if I think the risk is outweighed by the fuel savings. It's not your business to tell me I have to run my lights if I have personal reasons not to use them."

Well, it is your personal risk that is greatest; if you drive without your lights, yours is the car most likely to get hit. But that's not the only risk; you put all the other users of the road at higher risk of colliding with you when you don't use your lights. Hence, we as a society require you to use your lights because it makes us all safer. Nobody complains about these laws; we all realize the communal good in requiring everybody to use their lights at night.

How exactly is refusing to vaccinate different?