Date of Award

January 2016

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)


School of Public Health

First Advisor

Linda Niccolai


IMPORTANCE: The majority of literature related to disparities in human papillomavirus (HPV) vaccination has been focused on sociodemographic differences in vaccine uptake. Now nearly ten years after the introduction of the vaccine, and with a better understanding of disparities in uptake, a small but growing body of evidence is beginning to examine the impacts of the vaccination campaign. Monitoring disparities in the impact of the vaccine is crucial in order to better understand the full implications of the vaccine and to properly guide future programs and recommendations.

OBJECTIVE: To systematically review the literature on the impact of the human papillomavirus vaccine on HPV-related outcomes, and to assess the potential differences in impact by various sociodemographic characteristics.

EVIDENCE REVIEW: We systematically searched the global literature using keyword searches of the Medline, PubMed, and Web of Science databases between January 1, 2007 and January 31st, 2016 to identify studies that met our inclusion criteria. Using a standardized protocol, two investigators independently abstracted information on relevant study characteristics including principle outcomes, methods, sociodemographic characteristics of the study population, and the statistical methods used by the authors to account for these factors. The quality of studies (potential for bias and confounding) was assessed by review of participant selection or recruitment procedures, and potential confounders considered in the statistical analyses. A total of 3,713 records were screened and 45 published studies were included. Results were summarized by method of statistical analysis.

FINDINGS: Of the 45 included articles, 22 articles did not collect information on sociodemographic variables and 23 collected at least one sociodemographic variable. Variables collected varied between studies and countries with the most commonly assessed being race, ethnicity, education, urbanization and geographic region of residence. Of the studies that collected sociodemographic information, the statistical methods used to account for these factors included adjusting (n=15), stratifying (n=5), stratifying and then adjusting (n=1), or no further analysis (n=2). Two of the stratified analyses found differences in outcome measures based on sociodemographic characteristics such as ethnicity, screening venue, poverty, and urban versus nonurban residence. Findings indicated that HPV 16/18 prevalence decreased across all screening venues and that there was a significant decrease among white women but the decrease among black women was less marked and not significant. Further, there was a strong and significant decline in CIN2+/AIS among census tracts that had a lower proportion of the population living in poverty, in nonurban counties, and of Black and Hispanic race/ethnicity. The remaining three studies that used a stratified analysis found no differences in the outcome measures.

CONCLUSION AND RELEVANCE: In order to gain a better understanding of the impact of the HPV vaccine on related outcomes, efforts should be made to conduct stratified analyses whenever sociodemographic information is available. Further, this review indicates that a higher overall uptake of the vaccine may reduce potential disparities in impact and therefore future efforts should focus on improving vaccine coverage.


This is an Open Access Thesis.