Sen. Rand Paul of Kentucky confirmed his membership in the “doctors who shouldn’t have gone into politics” club with his comments last week supporting the right of parents who don’t want their kids to be immunized. While acknowledging vaccines to be “one of the greatest medical breakthroughs that we have,” Paul asserted that they should be

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. He talked of “walking, talking, normal kids” who had been left with

” after getting several vaccines at once, and admitted that he had used an alternative schedule for his own children.

There is a lot of misinformation to unpack here. Yes, babies get more vaccines than they used to, but the vaccines themselves are far more purified. There is no support for the widely held belief that vaccines cause autism.  At the end of the day, however, I suspect that many parents will sympathize with Paul's assertion that "the state doesn't own your children; parents own their children."

It is a message that appeals not just to libertarians but to the broader principles of consumer choice and individual freedom.  Paul professes he can't see what the fuss is about. But vaccines don't fit with the libertarian model, and the history of measles—including the outbreak now spreading across the country from Disneyland—offers the perfect example why.

Paul is still enough of a doctor to assert that he is not anti-vaccine; he just thinks vaccines should be promoted by education rather than by compulsion. And he suggests that this is exactly how Americans have handled vaccines for most of their history. This is only a partial truth. Smallpox vaccination was mandatory in many states a century ago.  The heavy-handed enforcement of these laws did indeed provoke a lot of opposition. By the 1920s, most public health leaders concluded that compulsory vaccination was more trouble that it was worth. Starting with diphtheria immunization in the 1920s, they chose to rely on the methods of Madison Avenue—billboards, posters, and publicity campaigns—to promote vaccines. The same was true for polio vaccine in the 1950s, where the March of Dimes recruited the likes of Elvis Presley and Richard Nixon (not at the same time) to encourage the immunization. And when measles vaccine was licensed in the early 1960s, it became the centerpiece of massive eradication campaigns across the nation, a war on disease that paralleled the war on poverty.

But there was a problem. Though mass education campaigns initially had great success, as the awareness of the diseases they prevented declined, so did vaccination rates. This was especially true for measles. Before the vaccine, measles was almost a rite of passage of childhood. That did not make it benign. Children had high fevers for several days, developed a sunburn-like rash, and could be severely ill for two weeks. Though death was uncommon, complications could be severe. In the early 1960s, measles hospitalized about 48,000 Americans a year, about 4,000 of whom developed encephalitis that often left victims with long-term brain damage so devastating as to require institutional care.

Measles rates plummeted in response to the vaccine, but the virus was not defeated. Instead of being eradicated, measles continued to erupt in periodic outbreaks in the 1970s and 80s. Understanding why this happened illustrates how vaccines control disease.

Vaccines work at the level of populations rather than individuals. Two doses of measles vaccine, for example, induces immunity in about 97% of children. The remainder – including most babies less than 1 year old – are protected by those around them. When vaccination levels reach a certain threshold (94% in this case), measles stops circulating. While immunization rates in much of the country, on average, are close to that level, they are far lower in some communities, and it is those pockets that have been linked to most recent outbreaks.

Thus, the decision not to vaccinate your child is not just a personal decision. It has implications for others around you. The consumer model of medicine does not apply; we are all connected.

That is why the failure of educational campaigns led public health officials to return to mandatory vaccination, but with a new emphasis. They linked childhood vaccination to participation in the community – attending school or daycare.  This strategy has been spectacularly effective, and by 2000 home-grown measles had been eliminated from the United States; the only cases were imported by travelers from other countries.

At least that was true until the new wave of vaccine skepticism came along. I am a pediatrician as well as vaccine historian, and I'll remind parents who are hesitant about vaccines that no child is an island; their decision has implications for others.  I remember one father told me he understood this, but that, frankly, it "really is just about us."

I couldn't have said it better.  Libertarianism isn't good for kids.  And Rand Paul, a doctor, ought to know better.

Jeffrey P. Baker teaches history of medicine at  Duke University School of Medicine.  He is a vaccine historian who has written about vaccine controversies and the history of autism.

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