Health Affairs - At the Intersection of Health, Health Care and Policy

Health officials attest that immunizations are among the most successful interventions in public health. However, there remains a substantial unvaccinated population in the United States. We analyzed how state-level vaccination exemption laws affect immunization rates and the incidence of preventable disease. We measured the association between each component of state kindergarten vaccination exemption laws and state vaccination exemption rates from 2002 to 2012, using the Centers for Disease Control and Prevention’s annual school assessment reports. We found that policies such as requiring health department approval of nonmedical exemptions, requiring a physician to sign an exemption application, and having criminal or civil punishments for noncompliance with immunization requirements had a significant effect in reducing vaccine exemptions. Our exemption law effectiveness index identified eighteen states with the most effective laws and nine states with the least effective ones. The most effective states had lower incidences of pertussis, compared to other states. For policy makers interested in decreasing the number of vaccine exemptions in their state, our findings are of particular interest. I n recent years preventable diseases such as pertussis (whooping cough), measles, and mumps have been on the rise. Measles had largely been eliminated in the United States by 2000, but lately there has been a resurgence. On January 13, 2015, health officials warned that a Disneyland visitor was linked to at least seven cases of measles in California and two cases in Utah; six of those patients had not been vaccinated. By March 2015, California had 133 confirmed measles cases, and four other stateshad cases linking back to the Disneyland visitor. Among the measles patients in California for whom vaccination documentation was available, 57 were unvaccinated. Because vaccines rely in part on herd immunity for their effectiveness, this surge in disease has been popularly attributed to falling vaccination rates, particularly within local clusters such as those involved in the spread of measles in California from the infected Disneyland visitor. The United States does not have a national vaccination requirement. One way state policy makers incentivize people to vaccinate their children is through the educational system. Before a child can enter kindergarten in any state, she or he must either be vaccinated or have a vaccination exemption. In most states, kindergarten vaccination exemptions can be granted for medical reasons (the child has some physical ailment that prevents vaccination), religious reasons (vaccinations violate the parents’ religious beliefs), or philosophical reasons (for example, vaccinations are not in accordance with the parents’ philosophical beliefs). doi: 10.1377/hlthaff.2014.1428