In the last year, scientific journals such as Nature and Science have been reporting that the number of families opting out of having their children vaccinated for diphtheria-tetanus-pertussis (DTP) and measles-mumps-rubella (MMP) are increasing. While overall statistics show that somewhat more than 90 percent of children in the U.S. are vaccinated, which is the level considered necessary to provide population immunity, the trend has been steadily downward. Between 2008 and 2009, immunization for MMP dropped 3 percent.
More troublesome, as The Economist reported May 12, when the national statistics are disaggregated the numbers show the holdouts are congregating in pockets. Many counties and towns in Washington state, Oregon, Vermont and California are now well below the population immunity level. Unvaccinated children in pockets are more dangerous than if they are randomly spread around the country. In a more random distribution the people most vulnerable to disease outbreaks from the unvaccinated are newborn babies and children who cannot be vaccinated for medical reasons. In pockets, not only are those youngsters vulnerable but also all the other unprotected kids that are now living close together, making an epidemic more likely.
Adding to the proximity danger is that the types of families in these pockets are not fence-sitters who might be swayed by better information, but those who have ideological convictions that predispose them to ignore empirical evidence if it is counter to their belief system. And the ideologies make strange bedfellows.
One grouping can be found in the rural foothills of Californias Sierra Nevada, and in parts of Idaho and Vermont. These people belong to the conservative dont-tread-on-me persuasion and distrust all government recommendations simply because they come from the government.
In other pockets, such as some along the coast of California, Oregon and Washington state, the families are committed to the liberal organic-food-and-yoga lifestyle. Their distrust of anything unnatural disposes them to believe rumors that vaccinations are dangerous despite all scientific evidence to the contrary. They are also among the first parents in history with no memory of the maiming and killing caused by polio, tetanus, diphtheria or measles that occurred before vaccinations were available.
Another discouraging aspect of these ideological congregations is that education level seems to make little difference in their ability to better understand the danger they are brewing. Most in the anti-government groups have a high school or less education, but college degrees are prevalent in the natural food pockets. In fact, those with the most education seem more prone to be selectively fearful of certain technologies and infuriatingly inconsistent. They forswear vaccines but drive their kids around in cars, often talking on a cellphone.
The belief in both lifestyles that only things natural are safe leaves them vulnerable to another danger; alternative and Asian health practitioners who tell them their kids dont need vaccinations. They advise parents to improve their childrens immune system by having them consume the various herbs and supplemental concoctions the practitioners prescribe. None of these treatments have been shown in controlled clinical trials to be effective, and several times a year the Centers for Disease Control and Prevention publishes an alert list of herbal treatments that have caused serious illnesses. But part of these lifestyles is to ignore scientific findings.
The common advice suggested to reverse the holdout trend is for health workers and media health reporters to be more aggressive. The belief is that these professionals have been too complacent and need to take a stronger stand telling people both about the falseness of vaccination scare stories and the truthfulness concerning the real dangers when vaccination is avoided.
The May 26 edition of the magazine Nature reported that some studies, however, show that such aggressiveness does not always sway the ideologically motivated, and may even increase their resolve to not immunize.
Julie Leask the author of the Nature article, believes that the only way to make holdouts understand the danger is to let them experience it. That is already happening in California where an outbreak of whooping cough in 2010 put 455 children in the hospital and killed 10 of them. Leask believes that when the information about such disease outbreaks spread through Facebook and Twitter it will convince more holdouts to change their minds. At least the teenage unprotected may realize the danger they are in.
Unfortunately, Leask is probably right. Let us hope that it will take only a small number of outbreaks to provide the persuasion before any large epidemic occurs.
Garth Buchanan holds a doctorate in applied science and has 35 years of experience in operations research. Reach him at firstname.lastname@example.org.