Immunization Mandates, Vaccination Coverage, and Exemption Rates in the United States

BACKGROUND: Vaccination coverage among children entering kindergarten in the United States is high, but interstate variations exist. The relationship between state immunization laws and vaccination coverage has not been fully assessed. We evaluated associations of state laws on both measles, mumps, and rubella (MMR) and diphtheria, tetanus, and pertussis (DTaP) vaccination coverage and exemptions to school immunization requirements. METHODS: We conducted a retrospective, longitudinal analysis of the effect of state immunization laws on vaccination coverage and exemptions among US kindergarteners from SY 2008 to SY 2014. The primary outcome measures were state-level kindergarten entry vaccination coverage rates for 2-dose MMR and 4-dose DTaP vaccines. Secondary outcome measures included rates of state-level exemptions (ie, medical, religious, philosophical) to school immunization requirements. RESULTS: We found that state policies that refer to Advisory Committee on Immunization Practices recommendations were associated with 3.5% and 2.8% increases in MMR and DTaP vaccination rates. Health Department–led parental education was associated with 5.1% and 4.5% increases in vaccination rates. Permission of religious and philosophical exemptions was associated with 2.3% and 1.9% decreases in MMR and DTaP coverage, respectively, and a 1.5% increase in both total exemptions and nonmedical exemptions, respectively. CONCLUSIONS: We found higher vaccination coverage and lower nonmedical exemption rates for MMR and DTaP vaccines in states adopting Advisory Committee on Immunization Practices guidelines for school entry. Adherence to these best practices was a successful strategy to increase vaccination coverage and reduce vaccination exemptions.