Millions of Americans believe it is perfectly all right to put other people at risk of death and misery. These people are your friends, neighbors, and fellow citizens who refuse to have themselves or their children vaccinated against preventable infectious diseases.
Aside from the issue of child neglect, there would be no argument against allowing people to refuse government-required vaccination if they and their families were the only ones who suffered the consequences of their foolhardiness. But that is not the case in the real world. Let's first take a look at how vaccines have improved health, then consider the role of the state in promoting immunization.
Vaccines are among the most effective health care innovations ever devised. A November 2013 New England Journal of Medicine article, drawing on the University of Pittsburgh's Project Tycho database of infectious disease statistics since 1888, concluded that vaccinations since 1924 have prevented 103 million cases of polio, measles, rubella, mumps, hepatitis A, diphtheria, and pertussis. They have played a substantial role in greatly reducing death and hospitalization rates, as well as the sheer unpleasantness of being hobbled by disease.
A 2007 article in the Journal of the American Medical Association compared the annual average number of cases and resulting deaths of various diseases before the advent of vaccines to those occurring in 2006. Before an effective diphtheria vaccine was developed in the 1930s, for example, the disease infected about 21,000 people in the United States each year, killing 1,800. By 2006 both numbers were zero. Polio, too, went from deadly (16,000 cases, 1,900 deaths) to non-existent after vaccines were rolled out in the 1950s and 1960s. Chickenpox used to infect 4 million kids a year, hospitalize 11,000, and kill 105; within a decade of a vaccine being rolled out in the mid-1990s, infections had dropped to 600,000, resulting in 1,276 hospitalizations and 19 deaths. Similar dramatic results can be found with whooping cough, measles, rubella, and more.
And deaths don't tell the whole story. In the case of rubella, which went from infecting 48,000 people and killing 17 per year, to infecting just 17 and killing zero, there were damaging pass-on effects that no longer exist. Some 2,160 infants born to mothers infected by others were afflicted with congenital rubella syndrome-causing deafness, cloudy corneas, damaged hearts, and stunted intellects-as late as 1965. In 2006 that number was one.
It is certainly true that much of the decline in infectious disease mortality has occurred as a result of improved sanitation and water chlorination. A 2004 study by the Harvard University economist David Cutler and the National Bureau of Economic Research economist Grant Miller estimated that the provision of clean water "was responsible for nearly half of the total mortality reduction in major cities, three-quarters of the infant mortality reduction, and nearly two-thirds of the child mortality reduction." Providing clean water and pasteurized milk resulted in a steep decline in deadly waterborne infectious diseases. Improved nutrition also reduced mortality rates, enabling infants, children, and adults to fight off diseases that would have more likely killed their malnourished ancestors. But it is a simple fact that vaccines are the most effective tool yet devised for preventing contagious airborne diseases.
Vaccines do not always produce immunity, so a percentage of those who took the responsibility to be vaccinated remain vulnerable. Other defenseless people include infants who are too young to be vaccinated and individuals whose immune systems are compromised. In America today, it is estimated that about 10 million people are immuno-compromised through no fault of their own.
This brings us to the important issue of "herd immunity." Herd immunity works when most people in a community are immunized against an illness, greatly reducing the chances that an infected person can pass his microbes along to other susceptible people.
People who refuse vaccination for themselves and their children are free riding off of herd immunity. Even while receiving this benefit, the unvaccinated inflict the negative externality of being possible vectors of disease, threatening those 10 million most vulnerable to contagion.
Vaccines are like fences. Fences keep your neighbor's livestock out of your pastures and yours out of his. Similarly, vaccines separate people's microbes. Anti-vaccination folks are taking advantage of the fact that most people around them have chosen differently, thus acting as a firewall protecting them from disease. But if enough people refuse, that firewall comes down, and innocent people get hurt.
Oliver Wendell Holmes articulated a good libertarian principle when he said, "The right to swing my fist ends where the other man's nose begins." Holmes' observation is particularly salient in the case of whooping cough shots.
Infants cannot be vaccinated against whooping cough (pertussis), so their protection against this dangerous disease depends upon the fact that most of the rest of us are immunized. Unfortunately, as immunization refusals have increased in recent years, so have whooping cough infections. The annual number of pertussis cases fell from 200,000 pre-vaccine to a low of 1,010 in 1976. Last year, the number of reported cases rose to 48,277, the highest since 1955. Eighteen infants died of the disease in 2012, up from just four in 1976.
The trend is affecting other diseases as well. In 2005, an intentionally unvaccinated 17-year-old Indiana girl brought measles back with her from a visit to Romania, and ended up infecting 34 people. Most of them were also intentionally unvaccinated, but a medical technician who had been vaccinated caught the disease as well, and was hospitalized.
Another intentionally unvaccinated 7-year-old boy in San Diego sparked an outbreak of measles in 2008. The kid, who caught the disease in Switzerland, ended up spreading his illness to 11 other children, all of whom were also unvaccinated, putting one infant in the hospital. Forty-eight other children younger than vaccination age had to be quarantined.
Some people object to applying Holmes' aphorism by arguing that aggression can only occur when someone intends to hit someone else; microbes just happen. However, being intentionally unvaccinated against highly contagious airborne diseases is, to extend the metaphor, like walking down a street randomly swinging your fists without warning. You may not hit an innocent bystander, but you've substantially increased the chances. Those harmed by the irresponsibility of the unvaccinated are not being accorded the inherent equal dignity and rights every individual possesses. The autonomy of the unvaccinated is trumping the autonomy of those they put at risk.
As central to libertarian thinking as the non-aggression principle is, there are other tenets that also inform the philosophy. One such is the harm principle, as outlined by John Stuart Mill. In On Liberty, Mill argued that "the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others." Vaccination clearly prevents harm to others.
So what are the best methods for increasing vaccination? Education and the incentives of the market have encouraged many Americans to get themselves and their children immunized, and surely those avenues of persuasion can and should be used more. Perhaps schools and daycare centers and pediatric clinics could attract clients by advertising their refusal to admit unvaccinated kids. Or social pressure might be exercised by parents who insist on assurances from other parents that their children are vaccinated before agreeing to playdates.
But it would be naive not to acknowledge the central role of government mandates in spreading immunization. By requiring that children entering school be vaccinated against many highly contagious diseases, states have greatly benefited the vast majority of Americans.
For the sake of social peace, vaccine opt-out loopholes based on religious and philosophical objections should be maintained. States should, however, amend their vaccine exemption laws to require that people who take advantage of them acknowledge in writing that they know their actions are considered by the medical community to be putting others at risk. This could potentially expose vaccine objectors to legal liability, should their decisions lead to infections that could have been prevented.
In terms of net human freedom, the tradeÂoff is clear: In exchange for punishment-free government requirements that contain opt-out loopholes, humans have freed themselves from hundreds of millions of infections from diseases that maimed and often killed people in recent memory. People who refuse vaccination are asserting that they have a right to "swing" their microbes at other people. That is wrong.