Correlates of high vaccination exemption rates among kindergartens

The present study was designed to characterize Arizona schools with high rates of permanent PBE among kindergartners, and to determine the degree to which they aggregate across the state.

Data for permanent personal belief exemptions (PBE) were accessed through the 2010-2011 kindergarten Immunization Data Report (IDR) from the Arizona Department of Health Services (AZDHS), and were linked to the 2009-2010 data from the National Center of Education Statistics (NCES). Incidence rate ratios (IRR) were calculated using negative binomial regression, and hotspots were identified using Getis-Ord Gi*.

Schools with highest proportion of white students compared to the lowest had the highest exemption rates (IRR=14.11; 95% confidence interval [CI], 9.47-21.03); furthermore charter schools and those with low prevalence of free and reduced lunches had significantly higher rates of PBE. Statewide analyses of PBE identified higher rates of permanent PBE in northern vs. southern Arizona, while a more focused examination of the central Arizona region demonstrated a pattern of increased PBE from west to east.

In Arizona, the profile of a high PBE school is that of a charter school attended by predominantly white, higher-income students. The local and statewide hotspots serve as a challenge that requires a multi-faceted approach that calls upon all healthcare professionals. It is important that both local and statewide pockets be targeted by local and state officials either to improve vaccination uptake or to employ careful monitoring to identify outbreaks at their onset.