​Authors analyzed contextual associations between medical care providers — pediatricians, family medical practitioners, and alternative medicine practitioners — and personal belief exemptions from mandated school entry vaccinations using California Department of Public Health records for 2010, 2011, and 2012. 

Provider data from federal sources and state records of alternative medicine providers, alongside controls for school factors, were used to estimate panel models. California Health Interview Survey (CHIS) data for 2011–2012 were used to control for two measures of child access to health care and medical service use.

Findings: The study reports each 10% increase in the relative proportion of pediatricians in a given primary care service area was associated with a statistically significant 11% decrease in personal belief exemption prevalence. The same increase in the proportion of family medical practitioners was associated with a 3.5% relative increase. 

Access to alternative medicine practitioners was also associated with a significantly higher personal belief exemptions prevalence.