Assessment of Vaccine Exemptions Among Wyoming School Children, 2009–10 and 2011–12

BACKGROUND:  

During 2010–11, varicella vaccination was an added requirement for school entrance in Wyoming. Although mandatory, state statutes allow parents to declare medical or religious exemptions to vaccination requirements. We evaluated vaccination exemption rates in Wyoming schools during 2009–10 and 2011–12 and assessed the impact of implementing a new childhood vaccine requirement.

METHODS:  

All public schools grades K-12 were required to report enrolled children’s immunization status for the 2009–10 and 2011–12 school years to the Wyoming Department of Health. Annual enrollment numbers obtained from the Wyoming Department of Education were used for denominators. Vaccination and exemption data were described by exemption category, vaccine, county, grade, sex, and rurality. For rurality, we used the U.S. Rural Urban Commuting Area (RUCA) codes four base tiers.

RESULTS:  

The proportion of children exempt for ≥1 vaccine increased from 1.2% (1,035/87,398) during 2009 to 1.9% (1,678/89,476) during 2011, with increases in all grades. Increases occurred in all four base tiers of U.S. RUCA codes, with the largest increase in the most rural areas — 1.5% exempt during 2009 to 2.6% exempt during 2011. In 2011, exemptions were lowest (1.5%) in urban areas and highest (2.6%) in the most rural areas; overall, varicella vaccine exemptions represented 67.1% (294/438) of single vaccination exemptions.  No differences existed by sex.

CONCLUSIONS:  

Implementation of a new vaccination requirement for school admission has led to an increased exemption rate across Wyoming, with the largest increase in rural areas. Continued yearly auditing and analysis of vaccine exemption data is needed for understanding long-term trends in vaccination exemption rates and for creating targeted interventions to decrease vaccination exemptions among Wyoming school-aged children.