Human papillomavirus vaccination in low- and middle-income countries: progression, barriers, and future prospective

Viral vector-based therapeutic HPV vaccines

Replication-defective viral vector vaccines have several advantages over conventional subunit vaccines, including potent antibody responses, cellular responses critical for eliminating pathogen-infected cells, and the induction of highly immunogenic and durable immune responses without adjuvants. The Human papillomavirus (HPV), a microorganism with over 200 genotypes, plays a crucial role in inducing human tumors, with the majority of HPV-related malignancies expressing HPV proteins. Tumors associated with HPV infection, most of which result from HPV16 infection, include those affecting the cervix, anus, vagina, penis, vulva, and oropharynx. In recent years, the development of therapeutic HPV vaccines utilizing viral vectors for the treatment of premalignant lesions or tumors caused by HPV infection has experienced rapid growth, with numerous research pipelines currently underway. Simultaneously, screening for optimal antigens requires more basic research and more optimized methods. In terms of preclinical research, we present the various models used to assess vaccine efficacy, highlighting their respective advantages and disadvantages. Further, we present current research status of therapeutic vaccines using HPV viral vectors, especially the indications, initial efficacy, combination drugs, etc. In general, this paper summarizes current viral vector therapeutic HPV vaccines in terms of HPV infection, antigen selection, vectors, efficacy evaluation, and progress in clinical trials.

Nanotherapy for human papillomavirus-associated cancers: breakthroughs and challenges

Human papillomaviruses (HPVs) are well-known causative agents of several cancers, yet selective therapies remain under investigation. Nanoparticles, for instance, are emerging as promising solutions to enhance the delivery and efficacy of therapeutic approaches. Despite the increasing number of nanotherapies offering advantages over current treatments, only one has advanced to clinical trials. This review highlights recent advances in nanotherapies for HPV-associated cancers, focusing on the delivery of small molecules, gene-targeted therapies, and vaccines. Some of the challenges faced in nanotherapies translation for clinical application are discussed, emphasizing the most used preclinical models that fail to accurately predict human responses, thereby hindering proper evaluation of nanotherapies. Additionally, we explore and discuss alternative promising new preclinical models that could pave the way for more effective nanotherapeutic evaluations.

Monitoring mouse papillomavirus-associated cancer development using longitudinal Pap smear screening

A substantial percentage of the population remains at risk for cervical cancer due to pre-existing human papillomavirus (HPV) infections, despite prophylactic vaccines. Early diagnosis and treatment are crucial for better disease outcomes. The development of new treatments heavily relies on suitable preclinical model systems. Recently, we established a mouse papillomavirus (MmuPV1) model that is relevant to HPV genital pathogenesis. In the current study, we validated the use of Papanicolaou (Pap) smears, a valuable early diagnostic tool for detecting HPV cervical cancer, to monitor disease progression in the MmuPV1 mouse model. Biweekly cervicovaginal swabs were collected from the MmuPV1-infected mice for viral DNA quantitation and cytology assessment. The Pap smear slides were evaluated for signs of epithelial cell abnormalities using the 2014 Bethesda system criteria. Tissues from the infected mice were harvested at various times post-viral infection for additional histological and virological assays. Over time, increased viral replication was consistent with higher levels of viral DNA, and it coincided with an uptick in epithelial cell abnormalities with higher severity scores noted as early as 10 weeks after viral infection. The cytological results also correlated with the histological evaluation of tissues harvested simultaneously. Both immunocompromised and immunocompetent mice with squamous cell carcinoma (SCC) cytology also developed vaginal SCCs. Notably, samples from the MmuPV1-infected mice exhibited similar cellular abnormalities compared to the corresponding human samples at similar disease stages. Hence, Pap smear screening proves to be an effective tool for the longitudinal monitoring of disease progression in the MmuPV1 mouse model.

IMPORTANCE

Papanicolaou (Pap) smear has saved millions of women's lives as a valuable early screening tool for detecting human papillomavirus (HPV) cervical precancers and cancer. However, more than 200,000 women in the United States alone remain at risk for cervical cancer due to pre-existing HPV infection-induced precancers, as there are currently no effective treatments for HPV-associated precancers and cancers other than invasive procedures including a loop electrosurgical excision procedure (LEEP) to remove abnormal tissues. In the current study, we validated the use of Pap smears to monitor disease progression in our recently established mouse papillomavirus model. To the best of our knowledge, this is the first study that provides compelling evidence of applying Pap smears from cervicovaginal swabs to monitor disease progression in mice. This HPV-relevant cytology assay will enable us to develop and test novel antiviral and anti-tumor therapies using this model to eliminate HPV-associated diseases and cancers.

Public health concern-driven insights and response of low- and middle-income nations to the World health Organization call for cervical cancer risk eradication

The heart shattering impact afflicted by the notorious cervical cancer is rising rapidly as it emerges as the second most prevalent cancer among women in the developing countries. There was an anticipated 604,127 observed reports and 341,831 fatalities reported worldwide in 2020. The mortality rate was 7.2 deaths per 100,000 women-years, while the age-standardized incidence rate was 13.3 cases per 100,000 women annually. In less developed countries, the accountability was around 87-90% of mortality and roughly 84% of newly diagnosed cases. Resource limitations, inadequate public awareness, and late-stage diagnosis aggravate the complications of cancer mitigation in these regions, compared to the higher income nations. While primary and secondary interventions come off as an enticing solution, international collaborations and the integration of technology also emerge as promising avenues for enhancing cancer care accessibility. This study aims to assess the progress of developing countries in meeting the World Health Organization's mandate to eliminate cervical cancer by scrutinizing the prevalence of cervical cancer incidence and mortality rates, evaluating the impact and execution of HPV vaccination initiatives, and analyzing proposals for cervical cancer eradication within these nations, our objective is to accelerate advancements towards the ultimate goal of eradicating cervical cancer.

Improving HPV Vaccination Uptake Among Adolescents in Low Resource Settings: Sociocultural and Socioeconomic Barriers and Facilitators

Background

Lower- and middle-income countries (LMICs) are disproportionately impacted by human papillomavirus (HPV) and would benefit from implementing the HPV vaccine. In the context of competing health priorities, utilizing scarce domestic infrastructure and human resources for HPV vaccination remains challenging for many LMICs. Given the high benefits of the HPV vaccine, the World Health Organization (WHO) is now encouraging for all countries, particularly LMICs, to introduce HPV vaccines into their routine immunization programs. Understanding the barriers and facilitators to HPV adolescent vaccine programs in LMICs may help strengthen how LMICs implement HPV vaccine programs, in turn, increasing HPV vaccine acceptance, uptake, and coverage.

Objective

To identify and assess barriers and facilitators to implementing adolescent HPV vaccination programs in LMICs.

Methods

This study comprised a review of literature assessing adolescent HPV vaccination in LMICs published after 2020 from a sociocultural perspective.

Results

Overall, the findings showed that LMICs should prioritize increasing HPV vaccine availability and HPV vaccine knowledge, particularly focusing on cancer prevention, as knowledge reduces misinformation and increases vaccine acceptance. Evidence suggests that factors promoting HPV vaccine uptake include fostering low vaccine hesitancy, integrating HPV vaccination as a primary school routine vaccination, and vaccinating both genders. A one-dose HPV vaccine may enable many LMICs to increase vaccine acceptance, uptake, and coverage while controlling financial, infrastructure, and human resource costs.

Conclusion

As HPV is one of the leading causes of death in many LMICs, implementing the HPV vaccine may be highly beneficial. Cohesive national HPV vaccine buy-in and understanding the success and challenges of prior LMIC HPV vaccine implementation is crucial to developing effective, efficient, and sustainable HPV vaccination programs.

Current status and future directions for the development of human papillomavirus vaccines

The development of human papillomavirus (HPV) vaccines has made substantive progress, as represented by the approval of five prophylactic vaccines since 2006. Generally, the deployment of prophylactic HPV vaccines is effective in preventing newly acquired infections and incidences of HPV-related malignancies. However, there is still a long way to go regarding the prevention of all HPV infections and the eradication of established HPV infections, as well as the subsequent progression to cancer. Optimizing prophylactic HPV vaccines by incorporating L1 proteins from more HPV subtypes, exploring adjuvants that reinforce cellular immune responses to eradicate HPV-infected cells, and developing therapeutic HPV vaccines used either alone or in combination with other cancer therapeutic modalities might bring about a new era getting closer to the vision to get rid of HPV infection and related diseases. Herein, we summarize strategies for the development of HPV vaccines, both prophylactic and therapeutic, with an emphasis on the selection of antigens and adjuvants, as well as implications for vaccine efficacy based on preclinical studies and clinical trials. Additionally, we outline current cutting-edge insights on formulation strategies, dosing schedules, and age expansion among HPV vaccine recipients, which might play important roles in addressing barriers to vaccine uptake, such as vaccine hesitancy and vaccine availability.

Human Papillomavirus Perceptions, Vaccine Uptake, and Sexual Risk Factors in Students Attending a Large Public Midwestern University

Background: It was to understand HPV vaccination patterns, uptake, perceptions, and sexual risk factors in students at a Midwest public university. Participants: Students were enrolled during the spring 2024 semester at the University of Iowa. Methods: A survey was developed and emailed to 28,095 students asking demographic, general and sexual health, and HPV-related questions. Results: The response rate was 4.9%, with 76% females and a median age of 22. The HPV vaccine uptake was 82%, with 88% recommending the vaccine. Parental preference was the main reason for being unvaccinated. The median age of sexual debut was 17 years, with a median of 2 sexual partners. Vaccination was associated with female, health science, sexually active, and COVID-19/influenza vaccinated students. Conclusions: HPV vaccine uptake at University of Iowa students is higher than the national and Iowa averages. Increased education regarding HPV vaccination is still needed, particularly in males, those not having sex, and those not receiving other vaccines.

Increased human papillomavirus viral load is correlated to higher severity of cervical disease and poorer clinical outcome: A systematic review

Cervical cancer is the fourth most common cancer in women worldwide and is caused by persistent infection with high-risk types of human papillomavirus (HPV). HPV viral load, the amount of HPV DNA in a sample, has been suggested to correlate with cervical disease severity, and with clinical outcome of cervical cancer. In this systematic review, we searched three databases (EMBASE, PubMed, Web of Science) to examine the current evidence on the association between HPV viral load in cervical samples and disease severity, as well as clinical outcome. After exclusion of articles not on HPV, cervical cancer, or containing clinical outcomes, 85 original studies involving 173 746 women were included. The vast majority (73/85 = 85.9%) reported that a higher viral load was correlated with higher disease severity or worse clinical outcome. Several studies reported either no correlation (3/85 = 3.5%), or the opposite correlation (9/85 = 10.6%); possible reasons being different categorization of HPV viral load levels, or the use of specific sampling methods. Despite variations in study design and populations, the above findings suggest that HPV viral load is correlated to clinical outcome, and may become an important biomarker for treatment selection and response monitoring for cervical cancer.

Integration of Ultrasound in Image-Guided Adaptive Brachytherapy in Cancer of the Uterine Cervix

Cervical cancer continues to be a public health concern, as it remains the second most common cancer despite screening programs. It is the third most common cause of cancer-related death for women, and the majority of cases happen in developing nations. The standard treatment for locally advanced cervical cancer involves the use of external beam radiation therapy, along with concurrent chemotherapy, followed by an image-guided adaptive brachytherapy (IGABT) boost. The five-year relative survival rate for European women diagnosed with cervical cancer was 62% between 2000 and 2007. Updated cervical cancer treatment guidelines based on IGABT have been developed by the Gynecological working group, which is composed of the Group Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology. The therapeutic strategy makes use of three-dimensional imaging, which can be tailored to the target volume and at-risk organs through the use of computed tomography or magnetic resonance imaging. Under anaesthesia, the brachytherapy implantation is carried out. Ultrasonography is utilised to assess the depth of the uterine cavity and to facilitate the dilation of the uterine canal during the application insertion. In this study, we examine data from the international literature regarding the application of ultrasound in cervical cancer brachytherapy.

Evaluation of a single-dose HPV vaccine strategy for promoting vaccine, health, and gender equity

Although several countries have adopted a single-dose human papillomavirus (HPV) vaccination strategy, many other countries continue to include multiple doses in their vaccination programmes. There are ethical reasons to transition to a single-dose strategy. We discuss how a single-dose HPV vaccination strategy advances equity in three dimensions: vaccine equity, health equity, and gender equity. Adopting a single-dose strategy eases pressure on vaccine supply, lowers programme costs, and is easier to distribute. This change facilitates vaccine procurement and implementation programmes (contributing to vaccine equity) and reaching hard to reach people or populations (contributing to health equity). A lower number of cases of HPV-related diseases that stem from greater vaccine distribution reduces the burden on women, who are at a higher risk of HPV-related disease or who act as caregivers, which prevents them from accessing opportunities that contribute to their empowerment (contributing to gender equity). Thus, pursuing the single-dose HPV vaccination programme strategy is ethically desirable.

Human Papillomavirus Vaccination Acceleration and Introduction in Sub-Saharan Africa: A Multi-Country Cohort Analysis

BACKGROUND

Cervical cancer, caused by human papillomavirus (HPV) infection, is the second-largest cancer killer of women in low- and middle-income countries. The brunt of the global burden is borne predominantly in Sub-Saharan Africa. In 2020 alone, 70,000 of the 100,000 infected women in Africa died from it, thereby making up 21% of global cervical cancer mortality. The introduction of the HPV vaccine into the National Immunization Program was expected to change the trajectory. However, uptake of the vaccination has been poor, especially for the second dose. Only about half of the countries in Africa currently provide the vaccine. Without urgent intervention, the 2030 global cervical cancer elimination targets will be undermined. The study aims to understand the key challenges facing the HPV vaccine and to develop a roadmap to accelerate the uptake.

METHOD

Fourteen countries were purposively included using a cohort design methodology and the investigation spanned March-July 2023. The Africa region was stratified into three focus-group discussion cohorts (Abidjan, Nairobi and Dar es Salaam), comprising pre-selected countries that have already and those about to introduce the HPV vaccine. In each country, the EPI manager, the NITAG chair or representatives and an HPV-focal researcher were selected participants. The methods involved a collaborative and knowledge-sharing format through regional and country-specific discussions, plenary discussions, and workshop-style group missions.

RESULTS

The study reached a total of 78 key stakeholders, comprising 30 participants in cohort one, 21 in cohort two and 27 in cohort three. Key outcomes included the prevalence of declining HPV2 vaccination across all countries in the region; country-specific barriers impeding uptake were identified and strategy for accelerating vaccination demand initiated, e.g., utilizing investments from COVID-19 (e.g., electronic registry and multisector coordination); individual countries developing their respective HPV vaccination recovery and acceleration roadmaps; the identification and inclusion of a zero-dose catch-up strategy into the vaccination roadmaps; support for a transition from multiple-doses to a single-dose HPV vaccine; the incorporation of implementation science research to support the decision-making process such as vaccine choices, doses and understanding behavior.

CONCLUSION

Beyond research, the study shows the significance of scientific approaches that are not limited to understanding problems, but are also solution-oriented, e.g., development of roadmaps to overcome barriers against HPV vaccination uptake.

Monitoring HPV Prevalence and Risk Cofactors for Abnormal Cytology in the Post-Vaccination Period among Croatian Women

The incidence and mortality rate of cervical cancer in Croatia remains a health challenge despite screening efforts. Besides the persistent infection with HPV, the development of cancer is also associated with some cofactors. The goal of this study was to assess circulating HPV genotypes and risk factors for the development of cervical precancer after almost 16 years from the onset of HPV vaccination in Croatia. In this study, a total of 321 women attending gynecological care were evaluated. Relevant medical and demographic information, including cytology, were collected. HPV genotyping was performed by PCR. Comparing the HPV types found in circulation in the pre-vaccination (1999-2015) and post-vaccination periods (2020-2023), a statistically significant reduction in HPV 31 was noted, while the overall prevalence increased in the post-vaccination period. Besides the expected HPV positivity as a risk factor, the history of smoking was associated with LSIL or worse cytology at enrollment. For the first time, this population study revealed a statistically significant shift in the HPV genotype in the post-vaccination period, as well as the confirmation of risk factors for the development of abnormal cytology among Croatian women.

Chronic Viral Infections and Cancer, Openings for Therapies and Vaccines

Infections are responsible for approximately one out of six cases of cancer worldwide [...].

The acceptability of HPV vaginal self-sampling for cervical cancer screening in Latin America: A systematic review

Objective

This review summarizes women's acceptability of vaginal self-sampling for cervical cancer screening in Latin America.

Study design

Systematic review.

Method

A systematic literature search was performed in PubMed, Web of Science, and Embase regarding the acceptance of HPV vaginal self-sampling by women over 18 years old. Articles were selected for research that was conducted in Latin America and published between January 1st, 1993, and December 31st, 2022.

Results

Fifteen publications were included. Eight publications reported an acceptance of HPV self-sampling as high as 80%, six papers found an acceptance rate between 50 and 80% and only one found an acceptance rate of less than 50%. Based on non-standardized questionnaires, women considered self-sampling more comfortable, easier, and less painful than conventional cytology. The procedure was associated with less embarrassment and a greater sense of privacy.

Conclusion

HPV vaginal-self sampling appears to be an acceptable screening method amongst eligible Latin American women.

Empowering Women's Health: Insights Into HPV Vaccination and the Prevention of Invasive Cervical Cancer

This review article provides a comprehensive analysis of the role of human papillomavirus (HPV) vaccination in empowering women's health by preventing invasive cervical cancer. Cervical cancer remains a significant global health concern, with HPV infection identified as a primary causative factor. The review synthesizes current research findings, epidemiological data, and clinical outcomes to offer a nuanced understanding of the impact of HPV vaccination on cervical cancer prevention. The article explores the biology of HPV, emphasizing its association with cervical carcinogenesis and the development of precancerous lesions. It delves into the epidemiology of HPV infection, highlighting the global prevalence and the burden of cervical cancer, particularly in low-resource settings. The socio-economic factors influencing HPV transmission and cervical cancer incidence are also discussed. The focus of the review is on the efficacy and safety of HPV vaccines, including an examination of vaccine types, dosages, and long-term effectiveness. Insights into the immunological responses triggered by vaccination, as well as the duration of protection against HPV infection and associated cancers, are presented. Special attention is given to addressing myths and misconceptions surrounding HPV vaccination, aiming to enhance public awareness and acceptance. Additionally, the review discusses the impact of vaccination programs on population-wide HPV prevalence and the subsequent reduction in cervical cancer rates. It explores challenges related to vaccine accessibility, affordability, and coverage, especially in underserved populations. Strategies for improving vaccine uptake and ensuring equitable distribution are considered, with a focus on empowering women through education and healthcare access. Furthermore, the article touches upon emerging trends in HPV research, such as the development of next-generation vaccines, therapeutic interventions for existing infections, and the potential for global HPV elimination. The integration of HPV vaccination into comprehensive women's health programs is advocated, emphasizing the importance of a holistic approach to cervical cancer prevention. In conclusion, this review provides a multifaceted exploration of HPV vaccination as a pivotal tool in empowering women's health by preventing invasive cervical cancer. The synthesis of current knowledge underscores the need for continued research, education, and global collaboration to ensure the widespread success of HPV vaccination initiatives, ultimately contributing to the advancement of women's health worldwide.

Dataset for vaginal human papillomavirus infection among adolescent and early adult girls in Jos, Nigeria

OBJECTIVES

To assess risk factors for HPV infection, determine knowledge about HPV vaccines, assess willingness to receive the HPV vaccine among adolescent and early adult girls in Nigeria, we administered a structured questionnaire. We also collected samples to determine the prevalence and patterns of HPV infections.

DATA DESCRIPTION

The dataset contains the responses of 205 participants from 10 randomly selected public and private secondary schools in Jos, Nigeria. The data includes information on risk factors for HPV infections such as sexual behaviours, knowledge about HPV vaccine and willingness to receive the vaccine. This is valuable information that can be compared to data from studies in other environments or to determine changes in the pattern of risk factors and HPV prevalence in this population over time.

Trend of HPV Molecular Epidemiology in the Post-Vaccine Era: A 10-Year Study

Cervical cancer, a major health concern among women worldwide, is closely linked to human papillomavirus (HPV) infection. This study explores the evolving landscape of HPV molecular epidemiology in Taiwan over a decade (2010-2020), where prophylactic HPV vaccination has been implemented since 2007. Analyzing data from 40,561 vaginal swab samples, with 42.0% testing positive for HPV, we reveal shifting trends in HPV genotype distribution and infection patterns. The 12 high-risk genotypes, in order of decreasing percentage, were HPV 52, 58, 16, 18, 51, 56, 39, 59, 33, 31, 45, and 35. The predominant genotypes were HPV 52, 58, and 16, accounting for over 70% of cases annually. The proportions of high-risk and non-high-risk HPV infections varied across age groups. High-risk infections predominated in sexually active individuals aged 30-50 and were mixed-type infections. The composition of high-risk HPV genotypes was generally stable over time; however, HPV31, 33, 39, and 51 significantly decreased over the decade. Of the strains, HPV31 and 33 are shielded by the nonavalent HPV vaccine. However, no reduction was noted for the other seven genotypes. This study offers valuable insights into the post-vaccine HPV epidemiology. Future investigations should delve into HPV vaccines' effects and their implications for cervical cancer prevention strategies. These findings underscore the need for continued surveillance and research to guide effective public health interventions targeting HPV-associated diseases.

Acceptability and readiness to promote human papillomavirus vaccination at ages 9-10 years: a feasibility study among North Carolina clinics

While 9-valent human papillomavirus (HPV) vaccination is approved by the US Food and Drug Administration for use in adolescents as young as age 9, providers typically recommend it at ages 11-12. Studies suggest that recommending HPV vaccination at 9 or 10 years of age could increase up-to-date vaccination by age 13, which could especially benefit rural populations with reduced access to primary health care and lower HPV vaccination coverage than urban areas. This study aimed to assess the feasibility of the age-9 recommendation of HPV vaccination in rural clinics. We conducted in-depth interviews with providers and staff from two primary care clinics in central North Carolina to understand attitudes toward recommending HPV vaccination to 9- and 10-year-olds. All interviewees agreed that HPV vaccination was important for cancer prevention and should be recommended before the onset of sexual activity, agreeing that HPV vaccination could be initiated before age 11 to improve timeliness and completion of the vaccination series. However, opinions were mixed on whether HPV vaccination should be initiated as young as 9 years old. Two key informants recruited from two university-affiliated clinics described their experiences recommending HPV vaccination to 9- and 10-year-olds, including a modified vaccination schedule that promotes HPV vaccination during routine well-child visits, prior to pubertal onset, and alongside other recommended adolescent vaccines. Age-9 recommendation and administration of HPV vaccination is possible with minimal changes to current clinical practices and could increase the convenience and acceptability of HPV vaccination in under-vaccinated settings.

HPV16 E6/E7 -based mRNA vaccine is therapeutic in mice bearing aggressive HPV-positive lesions

HPV (Human papillomavirus) affects 600,000 people worldwide each year. Almost all cervical cancers are associated with a past HPV infection. In particular, the positivity to the high-risk type HPV16 is detected in most of the invasive cervical cancers. FDA has approved prophylactic vaccines that protect against new HPV16 infections, but do not induce immunity in those patients with established infections or neoplasms. To date, no therapeutic vaccine targeting HPV16-associated lesions has been authorized. We have developed an mRNA-based vaccine against the HPV16 late oncoproteins E6 and E7, which are abundantly and exclusively expressed in high-grade squamous intraepithelial lesions (HSILs), a stage of the cervical disease that precedes the progression to carcinoma. Our in vitro and in vivo studies demonstrated that the translated mRNA is functional and elicits an antigen-specific adaptive immune response. Upon immunization with the vaccine, mice with HPV16+ lesions exhibited tumor growth inhibition, extension of lifespan, and development of a protective immune memory. In light of these results and the remarkable clinical success of mRNA vaccines against SARS-CoV2, we believe that our mRNA-based therapeutic vaccine has the potential to offer a non-invasive treatment alternative to the current standard of care for HPV16+ HSILs.