Closing The Gap: Catch-up HPV Vaccination Among Young Adults

Abstract

BACKGROUND: Human papillomavirus (HPV) is a common sexually transmitted viral infection worldwide. HPV causes approximately 91% of cervical cancers, 91% of anal cancers, 75% of vaginal cancers, 70% of oropharyngeal cancers, 69% of vulvar cancers, and 63% of penile cancers. Most HPV infections are asymptomatic and resolve spontaneously within 1-2 years. However, chronic infection from high-risk oncogenic HPV types may lead to precancerous lesions, which, if left untreated, may progress to cancer. HPV vaccines are an effective prophylaxis against HPV-related diseases. Routine HPV vaccination is recommended for individuals aged 9 to 26. Despite the proven safety and effectiveness of the HPV vaccine, the adolescent HPV vaccine coverage rates are dissatisfactory and leave many young adults at increased risk for developing vaccine-preventable HPV-related cancers. OBJECTIVES: This dissertation is comprised of three projects: (1) a qualitative evidence synthesis (QES) and systematic review, (2) a qualitative institutional assessment, and (3) a mixed-methods concept mapping study. The projects sought to address the following three aims: 1. Synthesize the literature to assess the barriers and facilitators of HPV vaccination in young adults. 2. Assess the institutional factors and processes influencing HPV vaccination on a college campus. 3. Identify and evaluate factors and strategies to increase HPV vaccination among unvaccinated young adults. METHODS: PRISMA and Cochrane guided a qualitative evidence synthesis (QES). In October 2023, seven databases were comprehensively searched to identify studies on HPV vaccination among young adults aged 18-26 years using qualitative study methods or analysis techniques. Studies were screened in a two-stage process guided by the eligibility criteria. Purposeful sampling of the eligible articles was performed to manage the qualitative data. The final included articles were evaluated for methodological strengths and limitations using the CASP quality assessment tool for qualitative studies. The GRADE-CERQual was applied to assess the confidence in synthesized qualitative findings. Key informant interviews were conducted as part of the institutional assessment, which was informed by the Consolidated Framework for Implementation Research (CFIR). Semi-structured interviews were conducted between February and March 2025 with personnel employed at the University of Arizona Campus Health Services (UACHS), a collegiate health clinic of a university in the southwestern United States. Eligible participants where those aged 18-26, enrolled as a student at a southwestern university and had not received the HPV vaccine or do not know if they received the HPV vaccine. Participants completed a concept mapping exercise. Participants generated qualitative statements in response to a topic prompt, organized and grouped the statements by perceived similarity, and rated each statement on a scale of perceived effectiveness. Multidimensional scaling (MDS) and hierarchical cluster analysis were conducted in GroupwisdomTM to develop a conceptual map of the data. Parallel coordinate plots were also generated for stratification analysis of participant demographics. RESULTS: Forty-two studies from 14 countries were included in the QES review, yielding 29 findings across 10 thematic areas. Some vaccine-eligible young adults believe they were ineligible for the vaccine because they were "too old" or were already having sex. Some participants also felt that using condoms or regularly getting screened negated the need for the HPV vaccine. Interestingly, parents continued to have a significant influence on whether young adults received the vaccine. Lastly, some challenges associated with getting vaccinated included the costs involved, the multiple appointments required to complete the series, and the accessibility of vaccination sites. Fourteen respondents from 6 UACHS departments were interviewed for the institutional assessment. Twenty-four findings were identified, comprising nine facilitators and 15 challenges. Facilitators of HPV vaccination included the engagement of multiple stakeholders across the organization, the availability of the HPV vaccine in various clinics, screening for HPV vaccination at every clinical encounter, and multi-modal communication and engagement efforts for vaccine information and education. Challenges included electronic medical record (EMR) querying and notification limitations, inconsistent follow-up and reminder procedures, and the social and political discourse about vaccines that hindered public trust. Twenty-four participants engaged in the concept mapping process. There were 41 statements generated, organized into five concept clusters: Media and Messaging, Information and Education, Promotion, Legal, and Accessibility. Accessibility was the highest-rated cluster for effectiveness, followed by Information and Education. Legal was rated the least effective cluster overall but was perceived to have a greater impact among Asian and Hispanic participants (compared to White participants), as well as moderate and liberal participants (compared to conservative participants). CONCLUSION: This dissertation highlights the complexity of factors across multiple ecological levels that may either aid or impede vaccination uptake among young adults. HPV vaccines remain the most effective form of prevention against HPV infections and HPV-associated cancers. The findings from this work present key considerations for designing and implementing interventions, programs, and policies aimed at increasing HPV vaccine coverage and reducing HPV-related health disparities.