Health Disparities in the Immunoprevention of Human Papillomavirus Infection and Associated Malignancies

Novel Vaccine Strategies and Factors to Consider in Addressing Health Disparities of HPV Infection and Cervical Cancer Development among Native American Women

Cervical cancer is the 4th most common type of cancer in women world-wide. Many factors play a role in cervical cancer development/progression that include genetics, social behaviors, social determinants of health, and even the microbiome. The prevalence of HPV infections and cervical cancer is high and often understudied among Native American communities. While effective HPV vaccines exist, less than 60% of 13- to 17-year-olds in the general population are up to date on their HPV vaccination as of 2020. Vaccination rates are higher among Native American adolescents, approximately 85% for females and 60% for males in the same age group. Unfortunately, the burden of cervical cancer remains high in many Native American populations. In this paper, we will discuss HPV infection, vaccination and the cervicovaginal microbiome with a Native American perspective. We will also provide insight into new strategies for developing novel methods and therapeutics to prevent HPV infections and limit HPV persistence and progression to cervical cancer in all populations.

Assessing sociodemographic differences in human papillomavirus vaccine impact studies in the United States: a systematic review using narrative synthesis

OBJECTIVES

Sociodemographic disparities in the incidence and mortality of human papillomavirus (HPV)-associated conditions have been well documented in the pre-HPV vaccine era. It is still unknown if the introduction of routine vaccination has been effective in reducing these prevaccine era inequalities. The purpose of this review was to determine the utilization of sociodemographic variables to assess for disparities in population-level HPV vaccine impact research and to evaluate the current evidence for disparities in the reduction of HPV-associated conditions after vaccine introduction in the United States (US).

STUDY DESIGN

A systematic review of the literature from January 2007 through March 2018 was carried out to identify studies evaluating the impact HPV vaccines have had on the rates of HPV infection, genital warts, and cervical dysplasia (cervical intraepithelial neoplasia grades 1+) in the US. An in-depth review was then performed to synthesize these data and to assess the way prior studies have reported and evaluated for potential disparities in the vaccine's impact within various racial, ethnic, and/or socio-economic subgroups of the population.

METHODS

Vaccine impact studies measure the change in the population-level burden of disease prelicensure versus postlicensure of the vaccine. We systematically searched PubMed/Medline and Embase, combining search terms related to the HPV vaccine, sentinel surveillance, and HPV-associated conditions. Eligible studies were those with population-level, postvaccine introduction data that were conducted in the US. Finally, a cited reference search was conducted for all included articles using the Web of Science platform that accesses three major citation indexes: Science Citation Index, Social Sciences Citation Index, and Arts and Humanities Citation Index. This allowed us to screen not only the articles that were cited by our final collection of studies but also the articles that used our selected studies as one of their references. The study protocol is registered in PROSPERO (#CRD42018107579).

RESULTS

Overall, 23 of the 4139 references retrieved assessed the population-level impact of HPV vaccines between January 1, 2007, and March 29, 2018. Among these, 13 (57%) reported sociodemographic data. Only two articles reported stratified results by sociodemographic factors, thereby allowing assessment for potential disparate impact. One of these studies described differences in the impact of the vaccine by race, ethnicity, and income.

CONCLUSION

Although approximately half of the studies that assessed the impact of the HPV vaccine measured sociodemographic characteristics, few presented results in a way that allowed for the identification of potential differences in impact between the relevant subgroups of the population. Determining to what extent, if any, vaccines are reducing known sociodemographic disparities is an important public health priority and an essential step in developing immunization strategies that are beneficial for all.

Human Papillomavirus Prevalence Among American Indian Women of the Great Plains

BACKGROUND

High-risk human papillomavirus (hrHPV) causes cervical cancer. In the United States, approximately 40% of women aged 14-59 years from all racial and ethnic groups are infected with HPV, and prevalence typically declines with age. However, American Indian (AI) women are insufficiently sampled to permit a population-specific estimate of hrHPV prevalence.

METHODS

Vaginal swabs were self-collected by 698 AI women aged 21-65 years from a tribal community in the Great Plains. We estimated the population prevalence of hrHPV and identified predominant genotypes.

RESULTS

The combined prevalence of hrHPV genotypes 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68 was 34.8%. HPV-51 (7.6%), HPV-58 (5.3%), HPV-52 (4.3%), HPV-18 (4.3%), and HPV-16 (3.9%) were most prevalent. hrHPV prevalence declined with age, from 42.2% in women aged 21-24 years to 27.9% in women aged 50-65 years.

CONCLUSIONS

HPV-51 was the single most prevalent oncogenic genotype. The combined prevalence of hrHPV among AI women in our sample was high, particularly among women aged 50-65 years, for whom hrHPV prevalence was approximately triple that of other races. Cervical cancer screening efforts should be increased, particularly among women from the community aged 30 years and older.

Factors Associated with Human Papillomavirus Vaccination among Women in the United States

Background

Human papillomavirus (HPV) infection is the most common sexually transmitted infection (STI) in the United States (US). HPV vaccines have the ability to prevent infection with HPV. The objective of this study was to assess the factors associated with HPV vaccination among women in the US.

Methods

Data from the 2014 Behavioral Risk Factor Surveillance System were used to assess predictors of HPV vaccination. A multivariable logistic regression analysis was used to estimate adjusted odds ratios (AORs) and 95% confidence intervals (95% CIs). Analyses were conducted using SAS Version 9.4.

Results

Factors that decreased the likelihood of receiving HPV vaccination included: being between the ages of 27–50 (AOR: 0.08; 95% CI: 0.06–0.11), having some college education, and residing in the South Black Belt States (AOR: 0.49; 95% CI: 0.31–0.78), Midwest (AOR: 0.63; 95% CI: 0.44–0.90), and the West (AOR: 0.37; 95% CI: 0.15–0.95). Factors that decreased the likelihood of receiving HPV vaccination to completion included: being Non-Hispanic Black (AOR: 0.26; 95% CI: 0.11–0.64), Hispanic (AOR: 0.26; 95% CI: 0.10–0.68), between the ages of 27–50 years (AOR: 0.46; 95% CI: 0.26–0.84), and residing in the Midwest (AOR: 0.36; 95% CI: 0.18–0.73) and South Remainder (non- Black Belt) states (AOR: 0.30; 95% CI: 0.09–0.93).

Conclusion

Our results suggest that sociodemographic disparities still exist in more recent data underscoring the urgent need for additional efforts to increase HPV vaccination in populations that are least likely to receive the vaccination.