Geographical disparities in human papillomavirus herd protection

BACKGROUND: Human papillomavirus (HPV) vaccination has occurred unequally across the United States, potentially contributing to uneven vaccine‐type HPV prevalence between regions. We examined whether emerging vaccine‐related herd protection exhibits regional differences among unvaccinated girls and women. METHODS: We evaluated the prevalence of vaginal HPV among women 14‐59 years of age from 2003 to 2014 using repeated cross‐sectional data from the National Health and Nutrition Examination Survey (NHANES). Women who provided an adequate vaginal swab sample were included. Vaginal prevalence of vaccine‐type HPV (types 6, 11, 16, 18) were examined in four regions of the United States between 2003 and 2014. We examined vaccine‐type HPV prevalence in 2007‐2014 in each US census region among younger participants (14‐34 years old) stratified by vaccination status to determine whether one or both groups contributed to uneven HPV prevalence. RESULTS: A total of 12 175 participants 14‐59 years of age met inclusion criteria. Vaccine‐type HPV prevalence decreased in all regions. Vaccine‐type HPV varied by region only among unvaccinated 14‐34 year olds, with a higher prevalence in the Midwest (13.8%, 95% confidence interval (CI): 10.7‐17.0) and South (12.5%, 95% CI: 10.2‐14.8) compared to the Northeast (8.9%, 95% CI: 6.5‐11.2). No regional variation in vaccine‐type HPV prevalence was observed among vaccinated participants. CONCLUSIONS: Higher prevalence of vaccine‐type HPV among unvaccinated women in the South and Midwest may contribute to regional disparities in HPV‐related cancer incidence, as emerging herd immunity may not be as strong in those regions.