Model-based small area estimation of Human papillomavirus (HPV) vaccine coverage among young adult women in Texas

Introduction: Methods to produce local estimates using data collected for larger regions are known as small area estimation (SAE). We demonstrate the use of multilevel, unit-level SAE to estimate human papillomavirus (HPV) vaccine coverage among females aged 18-26 in Texas counties. Methods: Multilevel (3 level: individual, county, public health region) random-intercept logit models were fit to HPV vaccination data (receipt of >=1 dose Gardasil®/HPV4) from the 2008 Behavioral Risk Factor Surveillance System (outcome and level 1 covariates) and a number of secondary sources (group-level covariates). Using estimated regression coefficients and standard errors from the final model, we simulated 10,000 datasets for each regression coefficient from the normal distribution and applied them to the logit model to estimate HPV vaccine coverage in each county. Results: County level estimates ranged from 1.9-23.8%, with a weighted state average of 11.4% (95% CI: 10.3, 12.5). Coverage amongst young adult females was highest in the Northern and Southeastern counties, and lowest in the Panhandle region of the state. Discussion: Small area analyses have been used in a variety of settings to assess a variety of health outcomes, and as shown in this study, can be used to highlight geographic disparities (and opportunities for intervention) in HPV vaccine coverage. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or the National Cancer Institute.