Vaccination Coverage Rates and Factors Associated With Incomplete Vaccination or Exemption Among School-age Children Based in Public Schools in New York State

Gaps in intentional and unintentional vaccination coverage persist and appear to be associated with socioeconomic factors that often drive social and geographic clustering.^1-3 Nonmedical exemptions to school vaccination requirements are rising nationally and in New York State (NYS).⁴ In states, including NYS, that only allow religious and medical exemptions, the association between socioeconomic characteristics and vaccination coverage and exemptions is unknown. The objective of this study was to assess vaccination coverage rates and factors associated with either incomplete vaccination or exemptions among school-age children in NYS public schools outside of New York City.

Children entering kindergarten through 12th grade in NYS between the academic years 2010-2011 and 2013-2014 were required to have at least 3 doses of diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine, 3 doses of poliovirus vaccine, 2 doses of measles-mumps-rubella (MMR) vaccine, 3 doses of hepatitis B vaccine, and a single dose of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) booster for 6th grade.⁵ The primary outcome measures were annual vaccination coverage and religious exemptions among children in grades K through 12. School immunization assessment survey results were obtained via the Freedom of Information Act from the NYS Department of Health. School district–level vaccination coverage and exemption data among public schoolchildren for 4 academic years (2010-2011 to 2013-2014) were matched to sociodemographic information obtained from the American Community Survey. The analyses were restricted to the 95% of school districts with matched data available from the survey. For each school district, the median percentage vaccination coverage and exemptions (medical or religious) were calculated. The 1% to 99% ranges were calculated to remove the effect of a few outliers. The Wilcoxon rank sum test was used to assess for trend across academic years. Poisson regression with robust error estimates was used to determine the association between rates of exemptions and underimmunization with districts’ income, education, and race distributions. The study met the criteria for exempt research. Therefore, State University of New York Upstate Medical University Institutional Review Board approval and informed consent were not required.

The number of reporting districts and schools ranged from 699 districts (2978 schools) in 2010-2011 to 695 districts (2878 schools) in 2013-2014. The median coverage for each mandated vaccine and the complete immunization series remained above 99% for the reported period overall. Most districts and individual schools maintained greater than 95% coverage for individual vaccines and the complete immunization series, while only 2.7% (18 of 661) of districts reported less than 95% coverage (Table 1). Among schools with less than 95% coverage, 85.5% (5089 of 5951) of missed vaccines were unintentional and unrelated to exemptions. Exemptions are uncommon in NYS public schools. From the 2010-2011 to 2013-2014 academic years, the median religious and medical exemption rates increased from 0.26% to 0.39% (P < .05) and 0.08% to 0.12% (P > .05), respectively. Children in districts with lower socioeconomic status were less likely to have received the complete series of required vaccines. While religious exemptions are rare, districts with larger income, more education, and greater percentage of residents of white race had significantly higher rates of religious exemptions (Table 2).

Public schools in NYS have high vaccination coverage, with current state immunization policies permitting only religious or medical exemptions. While religious exemptions are associated with higher socioeconomic status, the effect of these exemptions is small compared with unintended underimmunization, which disproportionately occurs in the economically challenged districts. The primary study limitation is the dependence on school immunization reports due in the fall semester, thus excluding immunizations completed after October. Public health practitioners should continue to enforce effective vaccination exemption policies and carefully examine barriers to vaccination among children in poorer school districts.

Corresponding Author: Jana Shaw, MD, MPH, MS, Department of Pediatrics, State University of New York Upstate Medical University, Golisano Children’s Hospital, 750 E Adams St, Syracuse, NY 13210 (shawja@upstate.edu).

Published Online: September 6, 2016. doi:10.1001/jamapediatrics.2016.1347

Author Contributions: Dr Nadeau had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Nadeau, Shaw.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Nadeau, McNutt.

Critical revision of the manuscript for important intellectual content: McNutt, Shaw.

Conflict of Interest Disclosures: Dr Shaw reported serving on a postapproval advisory board for Pfizer Inc. No other disclosures were reported.

Additional Contributions: Ellen Darabaner, MLS (Samaritan Medical Center, Watertown, New York), provided librarian assistance and expertise. Allison Krug, MPH (Artemis Biomedical Communications LLC, Bainbridge Island, Washington), contributed editorially to the manuscript, for which she received hourly compensation.