Who Take Advantage of Personal Belief Exemption Laws? A Multivariate Analysis of California Schools and Communities

Increasing vaccine exemption rates signal possible setbacks in public health, as children with a nonmedical exemption have been shown to be at increased risk of acquiring and transmitting measles and pertussis. However, who take advantage of such rules is not well-understood. This study aims to advance our understanding of the factors that drive personal belief exemption (PBE) rates in California schools and communities and ascertain how social-demographical forces have shaped these rates from 2007 to 2013. 

We employed spatial regression models to analyze 2007 and 2013 PBE data from California Department of Public Health. Key explanatory variables included income, education, race/ethnicity, school enrollment, school type, and past PBE rate.  To examine the robustness of the observed statistical relationships, we evaluated both school- and regional-level models at 3 distinct geographic scales of analysis.

We found that areas with higher household income and proportion of White population have higher overall rates of PBE and higher increases in PBE rates from 2007 to 2013 in California. Overall rates of PBE use doubled from 2007 to 2013 and schools with lower PBE in 2007 had higher rates of change than schools with high PBE in 2007. Private school type was associated with higher rates of change in PBEs. 

Our results suggest that health officials should focus on affluent neighborhoods and examine how to engage these parents to increase vaccine coverage.