A study of California kindergarteners’ exposure to personal belief exemptions (PBEs) from vaccinations at school found that PBE exposure increased from 2008 to 2010, indicating that more children are exposed to the risk of disease.
The author looked at California Department of Public Health data on kindergarteners to calculate measures of PBE exposure, for the whole state from 2008 to 2010 and by county for 2010. They measured prevalence, clustering and vulnerability to exposure to PBEs.
PBE exposure increased in every state-level measure. There was a greater prevalence of PBEs, greater clustering of kindergartners with PBEs, and more kindergarteners enrolled at schools with a high rate of PBEs. From 2008 to 2010, the PBE rate increased from 1.9 to 2.3, while the percentage of schools with more than 20 PBEs in the kindergarten cohort increased from 0.4 percent to 0.5 percent. The 2010 PBE rate in California was 2.3 per 100, and the school rate was 15.6 per 100. Over 7,000 kindergarteners went to schools with PBE rates over 20 per 100, including 2,700 kindergarteners with a PBE.
The author argues that her analysis can indicate high-risk areas so that health and education officials can target vaccine promotion intervention