Geospatial patterns in human papillomavirus vaccination uptake: evidence from uninsured and publicly insured children in North Carolina.

BACKGROUND: Human papillomavirus (HPV) vaccination coverage is far below the national objective set by Healthy People 2020. This paper explores spatial patterns in HPV vaccination uptake.
METHODS: Secondary data for publicly funded HPV vaccinations among age-eligible children from 2008 through 2013 from the North Carolina Immunization Registry (NCIR) were used in 2014 in an ecological analysis at the ZIP code tabulation area (ZCTA) level. We tested for spatial autocorrelation in unadjusted HPV vaccination rates using choropleth maps and Moran's I. We estimated nonspatial and spatial negative binomial models with spatially correlated random effects adjusted for demographic, economic, and healthcare variables drawn from the 2010 U.S. Census Bureau, 2008-2012 American Community Survey, 2010 ZIP Business Patterns, and the 2012-2013 Area Resource File.
RESULTS: The NCIR revealed areas of especially low rates in publicly funded HPV vaccinations among uninsured and means-tested, publicly insured children. For boys, but not girls, ZCTAs tended to have HPV vaccination rates that were similar to their neighbors. This result was partially explained by included ZCTA characteristics, but not wholly.
CONCLUSIONS: To the extent that the geospatial clustering of vaccination rates is due to causal influences from one ZCTA to another (e.g., through information networks), targeting interventions to increase HPV vaccination in one area could also lead to increases in neighboring areas. IMPACT: Spatial targeting of HPV vaccination, especially in clusters of low vaccination areas, could be an effective strategy to reduce the spread of HPV and related cancers. Cancer Epidemiol Biomarkers Prev; 24(3); 595-602. ©2015 AACR. ©2015 American Association for Cancer Research.