QuickScan Reviews in Pediatrics, August 15 2009

Background: Despite school requirements, deviations from recommended immunization schedules, including vaccine refusals, continue to increase. This trend poses significant risks, both to the individual and the community. Design: Review of historic and current literature. Discussion: By the early 1980s, the U.S. legally imposed school immunization requirements, with variations by state. Medical exemptions are currently allowed in all states, religious exemptions in most, and personal (philosophical) exemptions permitted in 21 states. In recent years, the rate of non-medical exemptions has dramatically increased, particularly in states that allow exemptions due to personal beliefs. Because there is marked geographic clustering of non-medical exemptions, the accumulation of susceptible children in a given area increases the risk of disease outbreaks in that region. Geographic clustering may occur due to characteristics of the local population, opinions of health care providers/community leaders, and local media coverage. Heterogeneity of school policies and attitudes of the school officials responsible for vaccine compliance may also influence exemption rates. As a result, complexity of procedures allowing non-medical exemptions is inversely proportional to the exemption rate. Studies have demonstrated that measles risk is 22 to 35 times higher in an unvaccinated child. During recent measles outbreaks, cases have almost universally occurred in unvaccinated individuals--either those with non-medical exemptions or those too young for vaccination. A case-control study reveals that parents of exempt children are much more likely than those of vaccinated children (51% to 60% vs 15% to 18%) to believe that their children have low susceptibility to vaccine-preventable diseases, the severity of the diseases is low, and that safety and efficacy of vaccines is low. The most frequent reason for vaccine refusal (in 69%) is concern regarding harmful effects of the vaccine. Primary care providers, including those of unvaccinated children, are cited by parents as the most frequent source of vaccine information, and several studies have highlighted the significant influence of clinicians on parental decisions regarding vaccines. Providers caring for a high proportion of exempt children are less likely to show confidence in vaccine safety and are less likely to perceive vaccines as providing benefit to individuals and the community. The American Academy of Pediatrics encourages clinicians with high confidence in vaccines to continue relationships with families that refuse immunization, and to engage in ongoing respectful dialogue to address parental concerns. Reviewer's Comments: Ironically, it is precisely because vaccines are so effective at reducing the incidence, morbidity, and mortality of infectious diseases that public perception of the threat of these diseases has changed so drastically. Provisions for personal exemptions to school immunization "requirements" suggest that there is essentially no requirement after all. Without effectively enforced school policies, our ability to control disease outbreaks through the use of vaccines greatly depends on heightened efforts to educate our patients.