Evidence for single-dose protection by the bivalent HPV vaccine-Review of the Costa Rica HPV vaccine trial and future research studies

Efficacy and immunogenicity of a single dose of human papillomavirus vaccine compared to multidose vaccination regimens or no vaccination: An updated systematic review of evidence from clinical trials

Objectives

This study systematically reviewed the published literature from clinical trials on the efficacy and immunogenicity of single-dose HPV vaccination compared to multidose schedules or no HPV vaccination.

Methods

Four databases were searched for relevant articles published from Jan-1999 to Feb-2023. Articles were assessed for eligibility for inclusion using pre-defined criteria. Relevant data were extracted from eligible articles and a descriptive quality assessment was performed for each study. A narrative data synthesis was conducted, examining HPV infection, other clinical outcomes and immunogenicity responses by dose schedule.

Results

Fifteen articles reporting data from six studies (all in healthy young females) were included. One article was included from each of three studies that prospectively randomised participants to receive a single HPV vaccine dose versus one or more comparator schedule(s). The other 12 articles reported data from three studies that randomised participants to receive multidose HPV vaccine (or control vaccine) schedules; in those studies, some participants failed to complete their allocated schedule, and evaluations were conducted to compare participants who actually received one, two or three doses. Across all efficacy studies, the incidence or prevalence of HPV16/18 infection was very low among HPV-vaccinated participants, regardless of the number of doses received; with no evidence for a difference between dose groups. In immunogenicity studies, HPV16/18 antibody seropositivity rates were high among all HPV-vaccinated participants. Antibody levels were significantly lower with one dose compared to two or three doses, but levels with one dose were stable and sustained to 11 years post-vaccination.

Conclusions

Results from this review support recent World Health Organization recommendations allowing either one- or two-dose HPV vaccination in healthy young females. Longer-term efficacy and immunogenicity data from ongoing studies are awaited. Randomised trials of single-dose HPV-vaccination are urgently needed in other populations, e.g. boys, older females and people with HIV.

Vaginal Microbiota and HPV in Latin America: A Narrative Review

With the expansion of human microbiome studies in the last 15 years, we have realized the immense implications of microbes in human health. The human holobiont is now accepted, given the commensal relationships with bacteria, fungi, parasites, viruses, and human cells. The cervicovaginal microbiota is a specific case within the human microbiome where diversity is lower to maintain a chemical barrier of protection against infections. This narrative review focuses on the vaginal microbiome. It summarizes key findings on how native bacteria protect women from disease or predispose them to damaging inflammatory processes with an emphasis on the role of HPV infections in Latin America, one of the world's regions with the highest cervical cancer prevalence.

The impact of alternate HPV vaccination and cervical screening strategies in Japan: a cost-effectiveness analysis

Background

The Japanese 2020 cervical screening guidelines recommend conventional cervical cytology screening every 2-years for women aged 20-69 years. The nonavalent human papillomavirus (HPV) vaccine has also recently been approved in Japan. We therefore evaluated the cost-effectiveness of cervical cancer screening strategies alongside universal nonavalent HPV vaccination of girls (12-16 years).

Methods

A cost-effectiveness analysis was performed using an age-specific Markov microsimulation model for Japan to evaluate total costs, quality adjusted life-years (QALYs) gained, incremental cost-effectiveness ratios (ICER), colposcopies, biopsies, precancer and cervical cancer treatments for 29 combined vaccination and screening strategies (conventional cytology, liquid-based cytology (LBC), HPV testing, and HPV self-collection). A cohort of 100,000 girls (12-16 years old) over a lifetime offered the nonavalent HPV vaccine was used (current vaccination coverage = 0.08%, current screening coverage = 43.7%). A discount rate of 3% was applied to costs and QALYs. Univariate and probabilistic sensitivity analysis was performed to assess robustness of the findings. Costs were reported in US dollars (2023).

Findings

Compared with conventional cytology, evaluated strategies would incur an additional cost of US$839,280-738,182,669 and gain 62,755-247,347 quality-adjusted-life-years. HPV testing distinguishing HPV16/18 with reflex LBC (3-yearly) would be most cost-effective (ICER = US$7511 per QALY gained). At a willingness-to-pay (WTP) of 1-times gross domestic product (GDP) per capita, the probability of it being cost-effective was 70%. At historically high vaccination coverage (70%) ICERs decreased overall but did not affect the ranking of the most cost-effective strategy. While a 5-yearly interval became more cost-effective than a 3-yearly interval. Including HPV self-collection for under-screened women made all strategies more cost-effective.

Interpretation

At current cervical screening participation (43.7%) and low vaccination coverage (<1.0%), HPV testing distinguishing HPV16/18 with reflex LBC (3-yearly) would be the most cost-effective screening strategy compared to conventional cytology (2-yearly).

Funding

Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (17H03589) and Grants of the National Cancer Center Japan (Gan Kenkyu Kaihatsuhi 31-A-20 and 2023-A-23).

Global perspectives of determinants influencing HPV vaccine introduction and scale-up in low- and middle-income countries

Achieving WHO cervical cancer elimination goals will necessitate efforts to increase HPV vaccine access and coverage in low-and-middle-income countries (LMICs). Although LMICs account for the majority of cervical cancer cases globally, scale-up of HPV vaccine programs and progress toward coverage targets in LMICs has been largely insufficient. Understanding the barriers and facilitators that stakeholders face in the introduction and scale-up of HPV vaccination programs will be pivotal in ensuring that LMICs are equipped to optimize the implementation of HPV vaccination programs. This qualitative study interviewed 13 global stakeholders categorized as either academic partners or global immunization partners to ascertain perspectives regarding factors affecting the introduction and scale-up of HPV vaccination programs in LMICs. Global stakeholders were selected as their perspectives have not been as readily highlighted within the literature despite their key role in HPV vaccination programming. The results of this investigation identified upstream (e.g., financial considerations, vaccine prioritization, global supply, capacity and delivery, and vaccine accessibility, equity, and ethics) and downstream (e.g., vaccine acceptability and hesitancy, communications, advocacy, and social mobilization) determinants that impact program introduction and scale-up and confirmed that strong political commitment and governance are significant in garnering support for HPV vaccines. As LMICs introduce HPV vaccines into their national immunization programs and develop plans for scaling up vaccination efforts, strategic approaches to communications and advocacy will also be needed to successfully meet coverage targets.

Durability of single-dose HPV vaccination in young Kenyan women: randomized controlled trial 3-year results

Cervical cancer burden is high where prophylactic vaccination and screening coverage are low. We demonstrated in a multicenter randomized, double-blind, controlled trial that single-dose human papillomavirus (HPV) vaccination had high vaccine efficacy (VE) against persistent infection at 18 months in Kenyan women. Here, we report findings of this trial through 3 years of follow-up. Overall, 2,275 healthy women aged 15-20 years were recruited and randomly assigned to receive bivalent (n = 760), nonavalent (n = 758) or control (n = 757) vaccine. The primary outcome was incident-persistent vaccine type-specific cervical HPV infection. The primary evaluation was superiority analysis in the modified intention-to-treat (mITT) HPV 16/18 and HPV 16/18/31/33/45/52/58 cohorts. The trial met its prespecified end points of vaccine type-specific persistent HPV infection. A total of 75 incident-persistent infections were detected in the HPV 16/18 mITT cohort: 2 in the bivalent group, 1 in the nonavalent group and 72 in the control group. Nonavalent VE was 98.8% (95% CI 91.3-99.8%, P < 0.0001) and bivalent VE was 97.5% (95% CI 90.0-99.4%, P < 0.0001). Overall, 89 persistent infections were detected in the HPV 16/18/31/33/45/52/58 mITT cohort: 5 in the nonavalent group and 84 in the control group; nonavalent VE was 95.5% (95% CI 89.0-98.2%, P < 0.0001). There were no vaccine-related severe adverse events. Three years after vaccination, single-dose HPV vaccination was highly efficacious, safe and conferred durable protection. ClinicalTrials.gov no. NCT03675256 .

Association of naturally acquired type-specific HPV antibodies and subsequent HPV re-detection: systematic review and meta-analysis

BACKGROUND

Understanding the role of naturally acquired (i.e., infection-induced) human papillomavirus (HPV) antibodies against reinfection is important given the high incidence of this sexually transmitted infection. However, the protective effect of naturally acquired antibodies in terms of the level of protection, duration, and differential effect by sex remains incompletely understood. We conducted a systematic review and a meta-analysis to (1) strengthen the evidence on the association between HPV antibodies acquired through past infection and subsequent type-specific HPV detection, (2) investigate the potential influence of type-specific HPV antibody levels, and (3) assess differential effects by HIV status.

METHODS

We searched Embase and Medline databases to identify studies which prospectively assessed the risk of type-specific HPV detection by baseline homologous HPV serostatus among unvaccinated individuals. Random-effect models were used to pool the measures of association of naturally acquired HPV antibodies against subsequent incident detection and persistent HPV positivity. Sources of heterogeneity for each type were assessed through subgroup analyses stratified by sex, anatomical site of infection, male sexual orientation, age group, and length of follow-up period. Evidence of a dose-response relationship of the association between levels of baseline HPV antibodies and type-specific HPV detection was assessed. Finally, we pooled estimates from publications reporting associations between HPV serostatus and type-specific HPV detection by baseline HIV status.

RESULTS

We identified 26 publications (16 independent studies, with 62,363 participants) reporting associations between baseline HPV serostatus and incident HPV detection, mainly for HPV-16 and HPV-18, the most detected HPV type. We found evidence of protective effects of baseline HPV seropositivity and subsequent detection of HPV DNA (0.70, 95% CI 0.61-0.80, NE = 11) and persistent HPV positivity (0.65, 95% CI 0.42-1.01, NE = 5) mainly for HPV-16 among females, but not among males, nor for HPV-18. Estimates from 8 studies suggested a negative dose-response relationship between HPV antibody level and subsequent detection among females. Finally, we did not observe any differential effect by baseline HIV status due to the limited number of studies available.

CONCLUSION

We did not find evidence that naturally acquired HPV antibodies protect against subsequent HPV positivity in males and provide only modest protection among females for HPV-16. One potential limitation to the interpretation of these findings is potential misclassification biases due to different causes.

Can prophylactic HPV vaccination reduce the recurrence of cervical lesions after surgery? Review and prospect

Women with HSIL typically undergo conization/LEEP to remove cervical lesions, but the risk of HSIL lesions returning after surgical treatment remains higher than in the general population. HPV vaccination is essential to prevent cervical cancer. However, the effect of prophylactic HPV vaccination on reducing the risk of recurrent cervical lesions after surgical treatment remains unclear. This review aims to analyze and summarize the latest literature on the role of prophylactic HPV vaccine in reducing the recurrence of cervical lesions after surgery in patients with HSIL, and to review and update the history, efficacy, effectiveness and safety of HPV vaccine, focusing on the current status of global HPV vaccine implementation and obstacles.

Latin American and the Caribbean Code Against Cancer 1st edition: Infections and cancer

About 13% of all cancers around the world are associated with infectious agents, particularly in low-resource settings. The main infectious agents associated with cancer are Helicobacter pylori (H. pylori), that causes gastric cancer, human papillomavirus (HPV) that causes cervical, vulvar, vaginal, penile, anal, and oropharyngeal cancer, hepatitis B and C viruses that cause liver cancer, and human immunodeficiency virus (HIV), associated with cancers of the cervix, Kaposi sarcoma (KS) and non-Hodgkin´s lymphoma. In Latin America and the Caribbean (LAC), about 150,000 cancer cases are caused annually by infections. The LAC Cancer Code Against Cancer consists of a set of 17 evidence-based and individual-level cancer prevention recommendations targeted to the general population, suited to the epidemiological, socioeconomic, and cultural conditions of the region, and tailored to the availability and accessibility of health-care systems. The recommendations with respect to infection-driven malignancies include testing and treating for H. pylori in the context of specific public health programs, vaccination against HPV and Hepatitis B Virus (HBV) and detection and treatment of chronic infections with HBV, Hepatitis C virus (HCV) and HIV, in addition to the promotion of safe sex and use of condoms to prevent sexually transmitted infections (STI). Countries, policy makers, health care systems and individuals should consider the adoption of these recommendations to help reduce the incidence and mortality of infection-related cancers in LAC, to improve quality of life of individuals and reduce the costs of cancer care in the region.

How to prevent human papillomavirus-related oropharyngeal cancer?

PURPOSE OF REVIEW

Human papillomavirus (HPV) is responsible of the increasing incidence rates of oropharyngeal squamous cell carcinoma (OPSCC) in high-income countries. This significant epidemiological change requires several and diverse prevention strategies.

RECENT FINDINGS

The cervical cancer prevention model is the paradigm of HPV-related cancer, and its success provides encouragement for the development of similar methods to prevent HPV-related OPSCC. However, there are some limitations that hinder its application in this disease. Here, we review the primary, secondary and tertiary prevention of HPV-related OPSCC and discuss some directions for future research.

SUMMARY

The development of new and targeted strategies to prevent HPV-related OPSCC is needed since they could definitely have a direct impact on the reduction of morbidity and mortality of this disease.

Living with HIV and Getting Vaccinated: A Narrative Review

After 40 years of its appearance, human immunodeficiency virus (HIV) infection remains a leading public health challenge worldwide. Since the introduction of antiretroviral treatment (ART), HIV infection has become a chronic condition, and people living with HIV could have life expectancies close to those of the general population. People with HIV often have an increased risk of infection or experience more severe morbidity following exposure to vaccine-preventable diseases. Nowadays, several vaccines are available against bacteria and viruses. However, national and international vaccination guidelines for people with HIV are heterogeneous, and not every vaccine is included. For these reasons, we aimed to perform a narrative review about the vaccinations available for adults living with HIV, reporting the most updated studies performed for each vaccine among this population. We performed a comprehensive literature search through electronic databases (Pubmed-MEDLINE and Embase) and search engines (Google Scholar). We included English peer-reviewed publications (articles and reviews) on HIV and vaccination. Despite widespread use and guideline recommendations, few vaccine trials have been conducted in people with HIV. In addition, not all vaccines are recommended for people with HIV, especially for those with low CD4 cells count. Clinicians should carefully collect the history of vaccinations and patients' acceptance and preferences and regularly check the presence of antibodies for vaccine-preventable pathogens.

Communication strategies to improve human papillomavirus (HPV) immunisation uptake among adolescents in sub-Saharan Africa: a systematic review and meta-analysis

OBJECTIVES

Developing countries face the greatest cervical cancer disease burden and mortality with suboptimal immunisation uptake. This review explores the communication strategies adopted, successes, challenges and lessons learnt in sub-Saharan countries to enhance human papillomavirus (HPV) immunisation.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Hinari, Cochrane Library, Trip database, CINAHL, Web of Science, Scopus and seven grey resources were searched through May 2022.

ELIGIBILITY CRITERIA

We included observational studies addressing communication strategies for HPV immunisation uptake.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers used standardised methods to search, screen and code included studies. Data extraction and assessment of risk of bias were done in duplicate to enhance validity of the results. Meta-analysis was conducted using the random-effects model. Findings were summarised and synthesised qualitatively.

RESULTS

Communication intervention to facilitate decision-making achieved uptake rate of 100% (95% CI 0.99% to 1.00%), followed by intervention to enable communication, which achieved 92% (95% CI 0.92% to 0.92%). Communication intervention to inform and educate achieved 90% (95% CI 0.90% to 0.90%).Targeting both healthcare workers and community leaders with the communication intervention achieved 95% (95% CI 0.91% to 0.98%), while teachers and school boards achieved 92% (95% CI 0.84% to 1.01%). Targeting policymakers achieved 86% (95% CI 0.78% to 0.93%).Based on the method of communication intervention delivery, use of training achieved an uptake rate of 85% (95% CI 0.84% to 0.87%); similarly, drama and dance achieved 85% (95% CI 0.84% to 0.86%). However, use of information, education and communication materials achieved 82% (95% CI 0.78% to 0.87%).

CONCLUSION

HPV vaccine communication is critical in ensuring that the community understands the importance of vaccination. The most effective communication strategies included those which educate the population about the HPV vaccine, facilitate decision-making on vaccine uptake and community ownership of the vaccination process immunisation.

PROSPERO REGISTRATION NUMBER

CRD42021243683.

Impact of HPV vaccination on HPV-related oral infections

BACKGROUND

Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide. Although the efficacy of the HPV vaccine in preventing the development of cervical pre-malignant lesions has been well demonstrated, the efficacy of the HPV vaccine in preventing HPV infection in the upper respiratory tract has been poorly studied.

METHODS

In the context of the IARC cohort study of two versus three doses of HPV vaccine in India, we compared the HPV type prevalence in the oral cavity of women vaccinated with three doses, two doses, or a single dose of quadrivalent HPV vaccine with that of unvaccinated women. A total of 997 oral samples, from 818 vaccinated women and 179 unvaccinated women, were collected at three study sites. All the participants were sexually active at the time of sample collection.

RESULTS

The age-standardized proportion (ASP) of HPV16/18 infections was 2.0 % (95 % CI, 1.0-3.0 %) in vaccinated women and 4.2 % (95 % CI, 1.2-7.2 %) in unvaccinated women. HPV16 was detected in 3.5 % of single-dose recipients, 1.2 % of two-dose recipients (days 1 and 180), and 1.5 % of three-dose recipients (days 1, 60, and 180), whereas 3.3 % of the unvaccinated women tested positive for HPV16. The same trend was observed for HPV18.

DISCUSSION

Our findings agree with those of previous studies on the efficacy of HPV vaccination in reducing oral HPV infections and provide indications that a single vaccine dose may be less efficient than two or three doses in preventing oral HPV infection.

Time trend and Age-Period-Cohort analysis of potentially HPV-related oral and pharyngeal cancer incidence in Singapore between 1968 and 2017

OBJECTIVES

To examine trends and age-period-cohort effects (APC) on oral and pharyngeal cancers incidence in Singapore between 1968 and 2017 by human papillomavirus (HPV) status.

METHODS

All diagnosed oral and pharyngeal cancers and population size were extracted from the Singapore Cancer Registry and the Department of Statistics Singapore, respectively. Anatomical subsites were used as a proxy for HPV infection. Prais-Winsten regression assessed trends of age-standardised incidence rate (ASIR) (per 100,000 person-years); Poisson regression assessed APC effects on HPV-related and HPV-unrelated cancers.

RESULTS

Over 50 years, 1,618 HPV-related and 2,977 HPV-unrelated oral and pharyngeal cancers were diagnosed, with the highest ASIR in Indians (6.93), followed by Chinese (2.81), and Malays (1.81). Overall, ASIR HPV-related cancers were stable while HPV-unrelated cancers decreased. The male-female ASIR ratio reduced from 5.82 (1968-1977) to 4.0 (2008-2017) for HPV-related cancers, and from 2.58 (1968-1977) to 1.52 (2008-2017) for HPV-unrelated cancers. HPV-unrelated ASIR in males decreased, but in females only among Indians. HPV-related ASIR decreased only among Indian females. The cohort born between 1983 and 1992 had the lowest incidence of HPV-related cancers in males but the highest in HPV-unrelated cancers. Period effect mainly contributed to HPV-related cancer among males with increased incidence after 1997. Overall, the age effect was more pronounced in males.

CONCLUSIONS

HPV-related cancers accounted for 1/3 of oral and pharyngeal cancers. A significant decline was observed only for HPV-unrelated cancers. The cohort effect was mainly attributed to HPV-unrelated cancer incidence, while the period effect largely contributed to HPV-related cancer incidence, but only among males.

Key ethical considerations to guide the adjudication of a single-dose HPV vaccine schedule

There is a high burden of human papillomavirus (HPV) associated cancers in low- and middle-income countries (LMICs). Reducing the recommended dosing schedule from two doses to one makes the vaccine schedule logistically simpler and lowers the cost. This could make the distribution of the current vaccine supply more equitable and lead to the protection of more people. However, the clinical trials studying the efficacy of a single-dose schedule have not yet delivered final results. Against this background, the question is whether a single-dose HPV vaccine recommendation is appropriate now, and if so, what are the ethical considerations of such a recommendation? We developed three ethical recommendations: (1) adopt a holistic view of evidence to justify policy decisions; (2) prioritize the reduction in global disparities in decision-making at all levels; and (3) be transparent in the reporting of how key stakeholder interests have shaped the collection and interpretation of the evidence, and ultimate decisions. The complex discussion regarding the HPV single-dose vaccine schedule highlights the need for in-depth engagement globally to improve our understanding of country-specific contexts, and how those contexts influence decisions regarding the HPV vaccine single-dose recommendation.

Therapeutic and diagnostic applications of nanoparticles in the management of COVID-19: a comprehensive overview

In December 2019, Coronavirus Disease 2019 (COVID-19) was reported in Wuhan, China. Comprehensive strategies for quick identification, prevention, control, and remedy of COVID-19 have been implemented until today. Advances in various nanoparticle-based technologies, including organic and inorganic nanoparticles, have created new perspectives in this field. These materials were extensively used to control COVID-19 because of their specific attribution to preparing antiviral face masks, various safety sensors, etc. In this review, the most current nanoparticle-based technologies, applications, and achievements against the coronavirus were summarized and highlighted. This paper also offers nanoparticle preventive, diagnostic, and treatment options to combat this pandemic.

Prophylactic Human Papillomavirus Vaccination: From the Origin to the Current State

Immunization is the most successful method in preventing and controlling infectious diseases, which has helped saving millions of lives worldwide. The discovery of the human papillomavirus (HPV) infection being associated with a variety of benign conditions and cancers has driven the development of prophylactic HPV vaccines. Currently, four HPV vaccines are available on the pharmaceutical market: Cervarix, Gardasil, Gardasil-9, and the recently developed Cecolin. Multiple studies have proven the HPV vaccines' safety and efficacy in preventing HPV-related diseases. Since 2006, when the first HPV vaccine was approved, more than 100 World Health Organization member countries reported the implementation of HPV immunization. However, HPV vaccination dread, concerns about its safety, and associated adverse outcomes have a significant impact on the HPV vaccine implementation campaigns all over the world. Many developed countries have successfully implemented HPV immunization and achieved tremendous progress in preventing HPV-related conditions. However, there are still many countries worldwide which have not created, or have not yet implemented, HPV vaccination campaigns, or have failed due to deficient realization plans associated with establishing successful HPV vaccination programs. Lack of proper HPV information campaigns, negative media reflection, and numerous myths and fake information have led to HPV vaccine rejection in many states. Thus, context-specific health educational interventions on HPV vaccination safety, effectiveness, and benefits are important to increase the vaccines' acceptance for efficacious prevention of HPV-associated conditions.

Can Adjuvant HPV Vaccination Be Helpful in the Prevention of Persistent/Recurrent Cervical Dysplasia after Surgical Treatment?—A Literature Review

Simple Summary

Primary prophylactic, early detection and the treatment of precancerous lesions are the main goals of cervical cancer screening. Despite effective surgical treatment methods, using loop electrosurgical excision procedures and conization, the overall risk of the recurrence of HSIL lesions remains at approximately 6.6%. There is increasing evidence of the potential role of HPV vaccines in the adjuvant setting and their impact on the reduction of disease recurrence. This review aims to analyze the up-to-date research concerning the use and efficacy of secondary human papilloma virus (HPV) vaccination as an adjuvant method to surgical treatment in patients diagnosed with cervical HSILs.

Abstract

Cervical cancer formation is preceded by precursor lesions, including low-grade squamous intraepithelial lesions (LSILs) and high-grade squamous intraepithelial lesions (HSILs), which are usually diagnosed in women of reproductive age. Despite the recent advanced diagnostic and treatment methods, including colposcopy, the loop electrosurgical excision procedure (LEEP), and surgical conization, the recurrence or residual disease affects as many as 6.6% of patients. The lesions are often associated with human papilloma virus (HPV) infection. As HPV persistence is the leading and only modifiable factor affecting the risk of progression of CIN lesions into high-grade cervical dysplasia and cancer, it has been proposed to conduct adjuvant vaccination in patients treated for high-grade cervical dysplasia. To date, no vaccine has been approved for therapeutic use in patients diagnosed with HSILs; however, attempts have been made to determine the use of HPV prophylactic vaccination to reduce recurrent HSILs and prevent cervical cancer. The aim of this review was to analyze the up-to-date literature concerning the possible use of secondary human papilloma virus (HPV) vaccination as an adjuvant method to surgical treatment in patients diagnosed with cervical HSILs. Adjuvant HPV vaccination after surgical treatment may reduce the risk of recurrent cervical dysplasia.

Understanding the public health value and defining preferred product characteristics for therapeutic human papillomavirus (HPV) vaccines: World Health Organization consultations, October 2021-March 2022

The World Health Organization (WHO) global strategy to eliminate cervical cancer (CxCa) could result in >62 million lives saved by 2120 if strategy targets are reached and maintained: 90% of adolescent girls receiving prophylactic human papillomavirus (HPV) vaccine, 70% of women receiving twice-lifetime cervical cancer screening, and 90% of cervical pre-cancer lesions and invasive CxCa treated. However, the cost and complexity of CxCa screening and treatment approaches has hampered scale-up, particularly in low- and middle-income countries (LMICs), and new approaches are needed. Therapeutic HPV vaccines (TxV), which could clear persistent high-risk HPV infection and/or cause regression of pre-cancerous lesions, are in early clinical development and might offer one such approach. During October 2021 to March 2022, WHO, in collaboration with the Bill and Melinda Gates Foundation, convened a series of global expert consultations to lay the groundwork for understanding the potential value of TxV in the context of current CxCa prevention efforts and for defining WHO preferred product characteristics (PPCs) for TxV. WHO PPCs describe preferences for vaccine attributes that would help optimize vaccine value and use in meeting the global public health need. This paper reports on the main discussion points and findings from the expert consultations. Experts identified several ways in which TxV might address challenges in current CxCa prevention programmes, but emphasized that the potential value of TxV will depend on their degree of efficacy and how quickly they can be developed and implemented relative to ongoing scale-up of existing interventions. Consultation participants also discussed potential use-cases for TxV, important PPC considerations (e.g., vaccine indications, target populations, and delivery strategies), and critical modelling needs for predicting TxV impact and cost-effectiveness.

A nanoparticle-based COVID-19 vaccine candidate elicits broad neutralizing antibodies and protects against SARS-CoV-2 infection

A vaccine candidate to SARS-CoV-2 was constructed by coupling the viral receptor binding domain (RBD) to the surface of the papaya mosaic virus (PapMV) nanoparticle (nano) to generate the RBD-PapMV vaccine. Immunization of mice with the coupled RBD-PapMV vaccine enhanced the antibody titers and the T-cell mediated immune response directed to the RBD antigen as compared to immunization with the non-coupled vaccine formulation (RBD + PapMV nano). Anti-RBD antibodies, generated in vaccinated animals, neutralized SARS-CoV-2 infection in vitro against the ancestral, Delta and the Omicron variants. At last, immunization of mice susceptible to the infection by SARS-CoV-2 (K18-hACE2 transgenic mice) with the RBD-PapMV vaccine induced protection to the ancestral SARS-CoV-2 infectious challenge. The induction of the broad neutralization against SARS-CoV-2 variants induced by the RBD-PapMV vaccine demonstrate the potential of the PapMV vaccine platform in the development of efficient vaccines against viral respiratory infections.

Modeling the health and economic implications of adopting a 1-dose 9-valent human papillomavirus vaccination regimen in a high-income country setting: An analysis in the United Kingdom

Although no human papillomavirus (HPV) vaccine is indicated for single-dose administration, some observational evidence suggests that a 1-dose regimen might reduce HPV infection risk to that achieved with 2 doses. This study estimated the potential health and economic outcomes associated with switching from a 2-dose HPV vaccination program for girls and boys aged 13-14 years to an off-label 9-valent (9vHPV), 1-dose regimen, accounting for the uncertainty of the effectiveness and durability of a single dose. A dynamic HPV transmission infection and disease model was adapted to the United Kingdom and included a probabilistic sensitivity analysis using estimated distributions for duration of protection of 1-dose and degree of protection of 1 relative to 2 doses. One-way sensitivity analyses of key inputs were performed. Outcomes included additional cancer and disease cases and the difference in net monetary benefit (NMB). The 1-dose program was predicted to result in 81,738 additional HPV-related cancer cases in males and females over 100 years compared to the 2-dose program, ranging from 36,673 to 134,347 additional cases (2.5% and 97.5% quantiles, respectively), and had a 7.8% probability of being cost-effective at the £20,000/quality-adjusted life years willingness-to-pay (WTP) threshold. In one-way sensitivity analyses, the number of additional cancer cases was sensitive to the median of the duration of protection distribution and coverage rates. The differences in NMBs were sensitive to the median of the duration of protection distribution, dose price and discount rate, but not coverage variations. Across sensitivity analyses, the probability of 1 dose being cost-effective vs 2 doses was < 50% at the standard WTP threshold. Adoption of a 1-dose 9vHPV vaccination program resulted in more vaccine-preventable HPV-related cancer and disease cases in males and females, introduced substantial uncertainty in health and economic outcomes, and had a low probability of being cost-effective compared to the 2-dose program.

Impact of one and two human papillomavirus (HPV) vaccine doses on community-level HPV prevalence in South African adolescent girls: study protocol and rationale for a pragmatic before-after design

INTRODUCTION

Vaccines against human papillomavirus (HPV) are the key to controlling cervical cancer in low/middle-income countries (LMICs) where incidence is highest, but there have been limited data from these settings on programme impact on HPV prevalence, and none in a population with endemic HIV infection. Furthermore, for many LMICs, the currently recommended two-dose schedule is difficult to deliver at scale, so there is mounting interest in a single-dose schedule.

METHODS AND ANALYSIS

The Human Papillomavirus One and Two-Dose Population Effectiveness Study is a hybrid impact evaluation of the national South African HPV vaccination programme, which has targeted grade 4 girls aged at least 9 years in public schools with two doses of vaccine since 2014, and a single-dose vaccine 'catch-up' programme delivered in one district in 2019. Impacts of both schedules on the prevalence of type-specific HPV infection will be measured using repeat cross-sectional surveys in adolescent girls and young women aged 17-18 years recruited at primary healthcare clinics in the four provinces. A baseline survey in 2019 measured HPV prevalence in the cohort who were ineligible for vaccination because they were already above the target age or grade under either the national programme or the single-dose programme in the selected district. HPV prevalence surveys are repeated in 2021 in the selected district, and in 2023 in all four provinces. We will calculate prevalence ratios to compare the prevalence of HPV types 16 and 18 in the single-dose (2021) and two-dose (2023) cohorts, with the vaccine-ineligible (2019) cohort.

ETHICS AND DISSEMINATION

The project was approved by the University of the Witwatersrand Human Research Ethics Committee (HREC #181005), and the University of New South Wales HREC (#181-005). Findings will be disseminated through peer-reviewed journals, scientific meetings, reports and community forums.

Human papillomavirus infection and seroprevalence among female university students in Mexico

Human papillomavirus (HPV) is one of the most common causes of sexually transmitted diseases, and the main etiology of cervical cancer. This study was aimed to assess type-specific cervical HPV prevalence and their association with HPV-specific antibodies in a cohort of female university students. HPV genotyping was performed by amplifying and sequencing a fragment of the L1 protein. A BLAST search was performed to identify HPV types. HPV-specific IgG antibodies were measured by ELISA in serum samples. A total of 129 women participated, with an average age of 21.75 years. The prevalence of vaginal HPV infection was 74.42%. The most predominant high-risk HPV types were 18 (13.95%), 31 (10.85%), and 16 (9.3%). We found that early age at coitarche and a higher number of sexual partners were significantly associated with a high prevalence of HPV infection. In addition to sexual behavior, we observed that the presence of serum-specific IgG antibodies against HPV can impact the prevalence of the virus. Seropositivity to HPV-16 and HPV-18 was associated with a lower prevalence of HPV-16, but not for other HPV types. Of note, there was a lower proportion of HPV-specific seropositivity in women who had the presence of the same HPV type in a cervical specimen, suggesting an immunoregulatory mechanism associated with the viral infection. In conclusion, the prevalence of HPV in university women was higher than expected and it was associated with early age of sexual debut, an increasing number of sexual partners, and a low proportion of HPV seropositivity.

Vaccine Strategies for Human Papillomavirus-Associated Head and Neck Cancers

Simple Summary

Human papillomavirus (HPV) is recognized as a significant risk factor for head and neck cancers worldwide, and it is the most common cause of oropharyngeal cancers in the United States. Here, we review the incidence and pathogenesis of HPV-related cancers, the development and approval of HPV prophylactic vaccines, and the use and effectiveness of HPV vaccines around the world. Furthermore, we discuss advances in the development of HPV therapeutic vaccines as well as its associated challenges.

Abstract

The rising incidence of oropharyngeal squamous cell cancers (OPSCC) in the United States is largely attributed to HPV. Prophylactic HPV vaccines have demonstrated effectiveness against oral infection of HPV 16 and HPV 18. We review the global epidemiology and biology of HPV-related cancers as well as the development of HPV vaccines and their use worldwide. We also review the various strategies and challenges in development of therapeutic HPV vaccines.

The effects of the national HPV vaccination programme in England, UK, on cervical cancer and grade 3 cervical intraepithelial neoplasia incidence: a register-based observational study

BACKGROUND

Human papillomavirus (HPV) immunisation with a bivalent vaccine (Cervarix) was introduced in England, UK, in Sept 1, 2008: routine vaccination was offered to girls aged 12-13 years with a catch-up programme for females aged 14-18 years in 2008-10. We quantified the early effect of this immunisation programme on cervical cancer and cervical carcinoma in situ, namely grade 3 cervical intraepithelial neoplasia (CIN3), registrations.

METHODS

In this observational study, we used an extension of the age-period-cohort Poisson model to estimate the relative risk of cervical cancer in three vaccinated cohorts compared with earlier cohorts that were not eligible for HPV vaccination. Data from a population-based cancer registry were extracted on Jan 26, 2021, and were assessed for diagnoses of cervical cancer and CIN3 from Jan 1, 2006 to June 30, 2019 in women aged 20-64 years and who were a resident in England. We used three vaccinated cohorts to account for differences in the school year in which the vaccine was offered and its national coverage. Adjustment for confounding was made using information on changes in cervical screening policy and historical events that affected cervical cancer incidence. Results were compared across models with different adjustments for confounders.

FINDINGS

We used data from a total of 13·7 million-years of follow-up of women aged 20 years to younger than 30 years. The estimated relative reduction in cervical cancer rates by age at vaccine offer were 34% (95% CI 25-41) for age 16-18 years (school year 12-13), 62% (52-71) for age 14-16 years (school year 10-11), and 87% (72-94) for age 12-13 years (school year 8), compared with the reference unvaccinated cohort. The corresponding risk reductions for CIN3 were 39% (95% CI 36-41) for those offered at age 16-18 years, 75% (72-77) for age 14-16 years, and 97% (96-98) for age 12-13 years. These results remained similar across models. We estimated that by June 30, 2019 there had been 448 (339-556) fewer than expected cervical cancers and 17 235 (15 919-18 552) fewer than expected cases of CIN3 in vaccinated cohorts in England.

INTERPRETATION

We observed a substantial reduction in cervical cancer and incidence of CIN3 in young women after the introduction of the HPV immunisation programme in England, especially in individuals who were offered the vaccine at age 12-13 years. The HPV immunisation programme has successfully almost eliminated cervical cancer in women born since Sept 1, 1995.

FUNDING

Cancer Research UK.

Human papillomavirus vaccination in the European Union/European Economic Area and globally: a moral dilemma

While many European Union/European Economic Area (EU/EEA) countries recently expanded human papillomavirus (HPV) vaccination to boys, HPV vaccine supply is currently limited for girls in low- and middle-income countries (LMIC) that are severely affected by HPV.Globally, about 50% of countries have introduced HPV vaccination. Some LMIC with high burden of cervical cancer have not yet introduced HPV vaccination, or are reaching suboptimal vaccination coverage. While WHO issued a call for cervical cancer elimination in 2018, a global shortage of HPV vaccines is currently predicted to last at least until 2024.We reviewed national policies of EU/EEA countries and recommendations of the World Health Organization (WHO) Strategic Advisory Group of Experts on immunisation to discuss current challenges and dose-sparing options. Several EU/EEA countries have extended HPV vaccination to boys and the European Cancer Organisation has issued a resolution for elimination of all HPV-associated cancers in both sexes. The European Centre for Disease Prevention and Control concluded in its 2020 guidance that cost-effectiveness of extending routine vaccination to boys depends on several context-specific factors. The extension of HPV vaccination to boys in EU/EEA countries may affect global availability of vaccines. Temporary dose-sparing options could be considered during the COVID-19 post-pandemic period.

Single-Dose Human Papillomavirus Vaccination in Low- and Middle-Income Countries-Time for Implementation?

Although cervical cancer is becoming a rare disease in high income regions, it is still a major health issue in low- and middle-income countries (LMICs). Cervical cancer develops after infection with a high-risk human papilloma virus (hrHPV), an infection against which vaccination has been possible since 2006. Large population immunization programs have been organized in many higher income countries, and yet they have not been implemented in most of the lower and middle-income nations. The cost of the vaccine, as well as the need for two doses impedes coverage in the most vulnerable groups. Studies are suggesting the efficacy of single dose vaccination, but so far only observational data are available while large, randomized, double-blind studies are still ongoing. In order to prevent and combat this disease, it is essential to inform the population of vaccination benefits and offer accessible programs in higher as well as low-and middle-income countries. In this commentary, we wish to focus our attention on the case for implementing single dose vaccination in lower- and middle-income nations.

Single-dose HPV vaccination efficacy among adolescent girls and young women in Kenya (the KEN SHE Study): study protocol for a randomized controlled trial

BACKGROUND

HPV infection is the primary cause of cervical cancer, a leading cause of cancer among women in Kenya and many sub-Saharan African countries. High coverage of HPV vaccination is a World Health Organization priority to eliminate cervical cancer globally, but vaccine supply and logistics limit widespread implementation of the current two or three dose HPV vaccine schedule.

METHODS

We are conducting an individual randomized controlled trial to evaluate whether a single dose of the bivalent (HPV 16/18) or nonavalent (HPV 16/18/31/33/45/52/58/6/11) HPV vaccine prevents persistent HPV infection, a surrogate marker for precancerous lesions and cervical cancer. The primary objective is to compare the efficacy of immediate, single-dose bivalent or nonavalent vaccination with delayed HPV vaccination. Kenyan women age 15-20 years old are randomized to immediate bivalent HPV and delayed meningococcal vaccine (group 1), immediate nonavalent HPV vaccine and delayed meningococcal vaccine (group 2), or immediate meningococcal vaccine and delayed HPV vaccine (group 3) with 36 months of follow-up. The primary outcome is persistent vaccine-type HPV infection by month 18 and by month 36 for the final durability outcome. The secondary objectives include to (1) evaluate non-inferiority of antibody titers among girls and adolescents (age 9 to 14 years) from another Tanzanian study, the DoRIS Study (NCT02834637), compared to KEN SHE Study participants; (2) assess the memory B cell immune response at months 36 and 37; and (3) estimate cost-effectiveness using the trial results and health economic models.

DISCUSSION

This study will evaluate single-dose HPV vaccine efficacy in Africa and has the potential to guide public health policy and increase HPV vaccine coverage. The secondary aims will assess generalizability of the trial results by evaluating immunobridging from younger ages, durability of the immune response, and the long-term health benefits and cost of single-dose HPV vaccine delivery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03675256 . Registered on September 18, 2018.

Australia's Role in Pneumococcal and Human Papillomavirus Vaccine Evaluation in Asia-Pacific

Australian researchers have made substantial contributions to the field of vaccinology over many decades. Two examples of this contribution relate to pneumococcal vaccines and the human papillomavirus (HPV) vaccine, with a focus on improving access to these vaccines in low- and lower-middle-income countries (LLMICs). Many LLMICs considering introducing one or both of these vaccines into their National Immunisation Programs face significant barriers such as cost, logistics associated with vaccine delivery. These countries also often lack the resources and expertise to undertake the necessary studies to evaluate vaccine performance. This review summarizes the role of Australia in the development and/or evaluation of pneumococcal vaccines and the HPV vaccine, including the use of alternative vaccine strategies among countries situated in the Asia-Pacific region. The outcomes of these research programs have had significant global health impacts, highlighting the importance of these vaccines in preventing pneumococcal disease as well as HPV-associated diseases.

Significant decline of HPV 6 infection and genital warts despite low HPV vaccination coverage in young women in Germany: a long-term prospective, cohort data analysis

BACKGROUND

The introduction of human papillomavirus (HPV) vaccination has resulted in a remarkable decline of genital warts in women and men, but in Germany historical rates of vaccination are relatively low. We report long-term surveillance data on changes in HPV 6 and HPV 11 infection and the prevalence of genital warts in young women in the Wolfsburg HPV epidemiological study (WOLVES).

METHODS

Women born in 1983/84, 1988/89, and 1993/94 participated in four cohorts between 2009/10 and 2014/15. Quadrivalent vaccination coverage and prevalence of HPV 6/11 infection and genital warts are reported for participants aged 19-22 years and 24-27 years at the time of sample collection. Statistical analyses were done to compare similarly aged participants using 2 × 2 contingency tables (Röhmel-Mansmann unconditional exact test; two-side alpha of 0.05).

RESULTS

A total of 2456 women were recruited. Between 2010 and 2015, there was a statistically significant decrease in the prevalence of HPV 6 infection among women aged 24-27 years (2.1% versus 0.0%; P < 0.0001) and women aged 19-22 years (2.0% versus 0.0%; P = 0.0056). There was no significant decline in HPV 11 infection. In total, 52 of 2341 participants were diagnosed with genital warts. There was a statistically significant drop in the risk of developing genital warts in women aged 24-27 years between 2010 and 2015 (4.7% versus 1.7%, respectively; P = 0.0018). The overall risk of developing genital warts in women aged 19-27 years decreased from 3.1% in 2010 to 1.2% in 2015 (P = 0.0022).

CONCLUSIONS

An increase in vaccination coverage was associated with a decreased prevalence of genital warts in young women. A protective effect greater than herd immunity alone was seen despite low vaccination rates. Quadrivalent vaccine had a protective effect on genital HPV 6 infection and an almost fully protective effect on the development of genital warts in the youngest population.

A Framework for Cervical Cancer Elimination in Low-and-Middle-Income Countries: A Scoping Review and Roadmap for Interventions and Research Priorities

The World Health Organization announced an ambitious call for cervical cancer elimination worldwide. With existing prevention and treatment modalities, cervical cancer elimination is now within reach for high-income countries. Despite limited financing and capacity constraints in low-and-middle-income countries (LMICs), prevention and control efforts can be supported through integrated services and new technologies. We conducted this scoping review to outline a roadmap toward cervical cancer elimination in LMICs and highlight evidence-based interventions and research priorities to accelerate cervical cancer elimination. We reviewed and synthesized literature from 2010 to 2020 on primary and secondary cervical cancer prevention strategies. In addition, we conducted expert interviews with gynecologic and infectious disease providers, researchers, and LMIC health officials. Using these data, we developed a logic model to summarize the current state of science and identified evidence gaps and priority research questions for each prevention strategy. The logic model for cervical cancer elimination maps the needs for improved collaboration between policy makers, production and supply, healthcare systems, providers, health workers, and communities. The model articulates responsibilities for stakeholders and visualizes processes to increase access to and coverage of prevention methods. We discuss the challenges of contextual factors and highlight innovation needs. Effective prevention methods include HPV vaccination, screening using visual inspection and HPV testing, and thermocoagulation. However, vaccine coverage remains low in LMICs. New strategies, including single-dose vaccination could enhance impact. Loss to follow-up and treatment delays could be addressed by improved same-day screen-and-treat technologies. We provide a practical framework to guide cervical cancer elimination in LMICs. The scoping review highlights existing and innovative strategies, unmet needs, and collaborations required to achieve elimination across implementation contexts.

Building Capacity for Global Cancer Research: Existing Opportunities and Future Directions

Cancer incidence and mortality are increasing in low- and middle-income countries (LMICs), where more than 75% of global cancer burden will occur by the year 2040. The primary drivers of cancer morbidity and mortality in LMICs are environmental and behavioral risk factors, inadequate prevention and early detection services, presence of comorbidities, and poor access to treatment and palliation. These same drivers also contribute to marked cancer health disparities in high-income countries. Studying cancer in LMICs provides opportunities to better understand and address these drivers to benefit populations worldwide, and reflecting this, global oncology as an academic discipline has grown substantially in recent years. However, sustaining this growth requires a uniquely trained workforce with the skills to pursue relevant, rigorous, and equitable global oncology research. Despite this need, dedicated global cancer research training programs remain somewhat nascent and uncoordinated. In this paper, we discuss efforts to address these gaps in global cancer research training at the US National Institutes of Health.

Does the number of doses matter? A qualitative study of HPV vaccination acceptability nested in a dose reduction trial in Tanzania

Background

The multi-dose regimen is a known barrier to successful human papillomavirus (HPV) vaccination. Emerging evidence suggests that one vaccine dose could protect against HPV. While there are clear advantages to a single dose schedule, beliefs about vaccine dosage in low and middle income countries (LMICs) are poorly understood. We investigated acceptability of dose-reduction among girls, and parents/guardians of girls, randomised to receive one, two or three doses in an HPV vaccine dose-reduction and immunobridging study (DoRIS trial) in Tanzania.

Methods

Semi-structured interviews with girls (n = 19), and parents/guardians of girls (n = 18), enrolled in the study and completing their vaccine course.

Results

Most participants said they entrusted decisions about the number of HPV vaccine doses to experts. Random allocation to the different dose groups did not feature highly in the decision to participate in the trial. Given a hypothetical choice, girls generally said they would prefer fewer doses in order to avoid the pain of injections. Parental views were mixed, with most wanting whichever dose was most efficacious. Nonetheless, a few parents equated a higher number of doses with greater protection.

Conclusion

Vaccine trials and programmes will need to employ careful messaging to explain that one dose offers sufficient protection against HPV should emerging evidence from ongoing dose-reduction clinical trials support this.

•

We interviewed girls, and parents/carers of girls, enrolled in an HPV Vaccine dose reduction trial.

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We found that enrolling in the trial in the context of community rumours required trust in the trial scientists.

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Scientists were trusted to decide on dosage; thus randomisation by dosage was not an acceptability issue.

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Girls preferred fewer vaccine doses in order to avoid injection-related pain.

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Parents/guardians generally wanted whichever dose regimen was most efficacious.

Head-to-Head Comparison of Modular Vaccines Developed Using Different Capsid Virus-Like Particle Backbones and Antigen Conjugation Systems

Capsid virus-like particles (cVLPs) are used as molecular scaffolds to increase the immunogenicity of displayed antigens. Modular platforms have been developed whereby antigens are attached to the surface of pre-assembled cVLPs. However, it remains unknown to what extent the employed cVLP backbone and conjugation system may influence the immune response elicited against the displayed antigen. Here, we performed a head-to-head comparison of antigen-specific IgG responses elicited by modular cVLP-vaccines differing by their employed cVLP backbone or conjugation system, respectively. Covalent antigen conjugation (i.e., employing the SpyTag/SpyCatcher system) resulted in significantly higher antigen-specific IgG titers compared to when using affinity-based conjugation (i.e., using biotin/streptavidin). The cVLP backbone also influenced the antigen-specific IgG response. Specifically, vaccines based on the bacteriophage AP205 cVLP elicited significantly higher antigen-specific IgG compared to corresponding vaccines using the human papillomavirus major capsid protein (HPV L1) cVLP. In addition, the AP205 cVLP platform mediated induction of antigen-specific IgG with a different subclass profile (i.e., higher IgG2a and IgG2b) compared to HPV L1 cVLP. These results demonstrate that the cVLP backbone and conjugation system can individually affect the IgG response elicited against a displayed antigen. These data will aid the understanding and process of tailoring modular cVLP vaccines to achieve improved immune responses.

Design of a Phase III immunogenicity and safety study evaluating two-dose regimens of 9-valent human papillomavirus (9vHPV) vaccine with extended dosing intervals

HPV vaccines are widely licensed as two-dose regimens, 6-12 months apart, for adolescents. Extended intervals between doses may be necessary due to resource constraints or vaccination program disruption. This international, multicenter, open-label study (NCT04708041) will evaluate the safety and immunogenicity of two-dose 9vHPV vaccine regimens with extended intervals of 1-5 years between doses in boys/girls compared with a standard three-dose regimen in women. Participants (planned N = 700) will be enrolled into six cohorts; Cohort 0: boys/girls aged 10-15 years who received one 9vHPV vaccine dose ≥1 year before enrollment without completing the series will receive one study dose of 9vHPV vaccine at day 1; Cohorts 1-4: HPV vaccination-naïve boys/girls aged 9-14 years will receive two doses (day 1 and month 12, 24, 36, or 60); Cohort 5: HPV vaccination-naïve women aged 16-26 years will receive three doses (day 1, months 2 and 6). Primary analyses will be based on serological responses 1 month after final vaccine dose. Co-primary objectives will (1) evaluate non-inferiority of geometric mean titers in each of Cohorts 1-4 versus Cohort 5, and (2) characterize antibody responses in Cohort 0, accounting for the interval between commercial and study vaccine dose. Injection-site and systemic adverse events (AEs) will be collected for 15 days and serious AEs for 12 months post-vaccination; vaccine-related serious AEs and deaths will be collected throughout the study. Results will inform completion of vaccination in individuals who did not complete the recommended series and guide implementation of vaccination programs in resource-limited settings.

Human Papillomavirus Vaccination After COVID-19

The current global novel coronavirus disease 2019 (COVID-19) pandemic threatens to derail the uptake of human papillomavirus (HPV) vaccination in low- and lower-middle income countries with major disruptions to routine immunization and the introduction of new vaccines delayed. This has a major impact on the World Health Organization cervical cancer elimination strategy, where it is dependent on HPV vaccination as well as cervical cancer screening and treatment. We discuss current opportunities and barriers to achieve high uptake of HPV vaccination in low- and lower-middle income countries as well as the impact of COVID-19. Implementation of 4 key recommendations for HPV vaccination in low- and lower-middle income countries is needed: increased global financial investment; improved vaccine supply and accelerated use of a single-dose schedule; education and social marketing; and adoption of universal school-based delivery. With the commitment of the global health community, the adoption of these strategies would underpin the effective elimination of cervical cancer.

Current and future vaccine clinical research with the licensed 2-, 4-, and 9-valent VLP HPV vaccines: What's ongoing, what's needed?

Prophylactic HPV vaccination has been a great public health success. For >20 years, clinical trials were conducted with the 2-, 4-, and/or 9-valent vaccines in young-adult females, mid-adult women, males, and adolescents. In all studies, the vaccines were highly efficacious, immunogenic, and well tolerated. Following vaccine licensure and utilization in national vaccine programs globally (real-world settings primarily in high income countries), numerous studies demonstrated that the vaccines continue to have an excellent safety profile and have dramatically reduced the incidence of genital warts, HPV vaccine-type prevalence, and precancerous lesions. Thirty-eight clinical trials with the currently licensed HPV vaccines are ongoing. Key questions being addressed in new trials include: efficacy against persistent infection and immunogenicity of a 1-dose regimen; efficacy of 3 doses in 20-45-year-old females; use in postpartum women and immunocompromised individuals (HIV, liver and kidney transplants); dose sparing via intradermal administration; use in combination with a PD1 monoclonal antibody in patients with cervical cancer; impact on recurrent disease in women undergoing cervical conization; persistence of protection; and use to prevent oropharyngeal cancer. Additional clinical research that should be conducted includes: long-term follow-up, particularly of 1- and 2-dose regimens; further evaluation of flexible 2-dose regimens; immunogenicity of 1- or 2-dose regimens in persons ≥15 years old and immunocompromised populations; safety and immunogenicity of 1 or 2 doses in children <9 years old; assessment of the vaccine in the prevention of transmission; interchangeability with newer HPV vaccines; additional concomitant use studies; and prevention of penile cancer and recurrent respiratory papillomatosis.

Screening for the prevention and early detection of cervical cancer: protocol for systematic reviews to inform Canadian recommendations

PURPOSE

To inform recommendations by the Canadian Task Force on Preventive Health Care on screening in primary care for the prevention and early detection of cervical cancer by systematically reviewing evidence of (a) effectiveness; (b) test accuracy; (c) individuals' values and preferences; and (d) strategies aimed at improving screening rates.

METHODS

De novo reviews will be conducted to evaluate effectiveness and to assess values and preferences. For test accuracy and strategies to improve screening rates, we will integrate studies from existing systematic reviews with search updates to the present. Two Cochrane reviews will provide evidence of adverse pregnancy outcomes from the conservative management of cervical intraepithelial neoplasia. We will search Medline, Embase, and Cochrane Central (except for individuals' values and preferences, where Medline, Scopus, and EconLit will be searched) via peer-reviewed search strategies and the reference lists of included studies and reviews. We will search ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. Two reviewers will screen potentially eligible studies and agree on those to include. Data will be extracted by one reviewer with verification by another. Two reviewers will independently assess risk of bias and reach consensus. Where possible and suitable, we will pool studies via meta-analysis. We will compare accuracy data per outcome and per comparison using the Rutter and Gatsonis hierarchical summary receiver operating characteristic model and report relative sensitivities and specificities. Findings on values and preferences will be synthesized using a narrative synthesis approach and thematic analysis, depending on study designs. Two reviewers will appraise the certainty of evidence for all outcomes using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and come to consensus.

DISCUSSION

The publication of guidance on screening in primary care for the prevention and early detection of cervical cancer by the Task Force in 2013 focused on cytology. Since 2013, new studies using human papillomavirus tests for cervical screening have been published that will improve our understanding of screening in primary care settings. This review will inform updated recommendations based on currently available studies and address key evidence gaps noted in our previous review.

Three-Year Follow-up of 2-Dose Versus 3-Dose HPV Vaccine

BACKGROUND AND OBJECTIVES

Human papillomavirus (HPV) antibody responses to the 9-valent human papillomavirus (9vHPV) vaccine among girls and boys (aged 9-14 years) receiving 2-dose regimens (months 0, 6 or 0, 12) were noninferior to a 3-dose regimen (months 0, 2, 6) in young women (aged 16-26 years) 4 weeks after last vaccination in an international, randomized, open-label trial (NCT01984697). We assessed response durability through month 36.

METHODS

Girls received 2 (months 0 and 6 [0, 6]: n = 301; months 0 and 12 [0, 12]: n = 151) or 3 doses (months 0,2, and 6 [0, 2, 6]: n = 301); boys received 2 doses ([0, 6]: n = 301; [0, 12]: n = 150); and young women received 3 doses ([0, 2, 6]: n = 314) of 9vHPV vaccine. Anti-HPV geometric mean titers (GMTs) were assessed by competitive Luminex immunoassay (cLIA) and immunoglobulin G-Luminex immunoassay (IgG-LIA) through month 36.

RESULTS

Anti-HPV GMTs were highest 1 month after the last 9vHPV vaccine regimen dose, decreased sharply during the subsequent 12 months, and then decreased more slowly. GMTs 2 to 2.5 years after the last regimen dose in girls and boys given 2 doses were generally similar to or greater than GMTs in young women given 3 doses. Across HPV types, most boys and girls who received 2 doses (cLIA: 81%-100%; IgG-LIA: 91%-100%) and young women who received 3 doses (cLIA: 78%-98%; IgG-LIA: 91%-100%) remained seropositive 2 to 2.5 years after the last regimen dose.

CONCLUSIONS

Antibody responses persisted through 2 to 2.5 years after the last dose of a 2-dose 9vHPV vaccine regimen in girls and boys. In girls and boys, antibody responses generated by 2 doses administered 6 to 12 months apart may be sufficient to induce high-level protective efficacy through at least 2 years after the second dose.

Current Status and Future Perspectives of Molecular Prevention Strategies for Cervical Cancers

Cervical cancer continues to be a global health problem; despite the potential for prevention through organised screening programmes that can detect and treat pre-cancerous lesions and also more recently, the availability of HPV (Human Papilloma Virus) vaccines. While routine screening with Pap smear testing has reduced the burden of cervical cancer in the high-income countries, the implementation of organised Pap-based screening programmes has not been found feasible in low-resource settings due to a lack of health care delivery infrastructure and limited health budgets. The well-established causal relationship between cervical cancer development and high-risk-HPV (HR-HPV) infection and the subsequent appreciation of the greater sensitivity of HPV testing over Pap smear cytology eventually lead to HPV testing being incorporated in the primary cervical cancer prevention programmes. An organised cervical cancer screening programme incorporating HR-HPV testing and HPV vaccine administration are currently considered to be the two major interventions for a comprehensive cervical cancer control programme worldwide. However, there are concerns that the requirement of a sophisticated infrastructure with its associated costs may make cervical cancer screening using molecular prevention by HPV testing impracticable to be implemented, especially in resource-poor, low-income countries. Visual Inspection with Acetic acid (VIA) represents one of the alternative methods for cervical cancer screening proposed for the countries with low- to middle-income resources and has gained popularity in India following the successful completion of two randomised controlled trials, but this method but has low sensitivity to detect cervical pre-cancers. More recently, the cost-effectiveness analysis of many studies including randomised controlled trials, even from the low-resource settings, has found that HPV testing is followed by treatment for HPV-positive women to be an effective and cost-effective screening strategy as compared to other screening methods including VIA. The incorporation of self-sampling and HPV testing by partial genotyping has the potential to significantly add to the effectiveness and the cost-effectiveness. The current status and future perspectives of molecular prevention strategies for cervical cancer prevention is further discussed.

Elicitation of Potent Neutralizing Antibody Responses by Designed Protein Nanoparticle Vaccines for SARS-CoV-2

A safe, effective, and scalable vaccine is needed to halt the ongoing SARS-CoV-2 pandemic. We describe the structure-based design of self-assembling protein nanoparticle immunogens that elicit potent and protective antibody responses against SARS-CoV-2 in mice. The nanoparticle vaccines display 60 SARS-CoV-2 spike receptor-binding domains (RBDs) in a highly immunogenic array and induce neutralizing antibody titers 10-fold higher than the prefusion-stabilized spike despite a 5-fold lower dose. Antibodies elicited by the RBD nanoparticles target multiple distinct epitopes, suggesting they may not be easily susceptible to escape mutations, and exhibit a lower binding:neutralizing ratio than convalescent human sera, which may minimize the risk of vaccine-associated enhanced respiratory disease. The high yield and stability of the assembled nanoparticles suggest that manufacture of the nanoparticle vaccines will be highly scalable. These results highlight the utility of robust antigen display platforms and have launched cGMP manufacturing efforts to advance the SARS-CoV-2-RBD nanoparticle vaccine into the clinic.

Elicitation of Potent Neutralizing Antibody Responses by Designed Protein Nanoparticle Vaccines for SARS-CoV-2

A safe, effective, and scalable vaccine is needed to halt the ongoing SARS-CoV-2 pandemic. We describe the structure-based design of self-assembling protein nanoparticle immunogens that elicit potent and protective antibody responses against SARS-CoV-2 in mice. The nanoparticle vaccines display 60 SARS-CoV-2 spike receptor-binding domains (RBDs) in a highly immunogenic array and induce neutralizing antibody titers 10-fold higher than the prefusion-stabilized spike despite a 5-fold lower dose. Antibodies elicited by the RBD nanoparticles target multiple distinct epitopes, suggesting they may not be easily susceptible to escape mutations, and exhibit a lower binding:neutralizing ratio than convalescent human sera, which may minimize the risk of vaccine-associated enhanced respiratory disease. The high yield and stability of the assembled nanoparticles suggest that manufacture of the nanoparticle vaccines will be highly scalable. These results highlight the utility of robust antigen display platforms and have launched cGMP manufacturing efforts to advance the SARS-CoV-2-RBD nanoparticle vaccine into the clinic.

Measurement of Human Papillomavirus-Specific Antibodies Using a Pseudovirion-Based ELISA Method

Human papillomavirus (HPV) vaccines are safe and effective in preventing HPV infection and cervical precancers. Neutralizing antibodies are thought to be the primary mechanism of protection for HPV vaccines, although the exact level required for protection has not been identified. Three common serological assays used in clinical trials to measure HPV antibodies are HPV pseudovirion-based neutralization assay (PBNA), competitive or total Luminex immunoassays (cLIA or LIA) and VLP-based enzyme linked immunosorbent assays (ELISA). While PBNA is the gold-standard for measuring neutralizing antibodies (NAb), it is labor intensive. Luminex immunoassay and VLP-ELISA are rapid and high throughput, but their reagents and equipment can be difficult to source. Nevertheless, data generated from these assays generally correlate well with PBNA. Here, we described a simplified high-throughput PsV-based ELISA for HPV antibody measurement, to circumvent some of the limitations of existing assays. Using this assay, we were able to differentiate HPV-specific IgG and IgM, and found a strong correlation between HPV-specific IgG and NAb levels, as previously determined by PBNA. This assay platform is simpler and less time-consuming than PBNA. In addition, the materials can be readily produced and obtained commercially. This assay can be used as an alternative method to measure HPV antibodies.

One-Dose Human Papillomavirus Vaccination and the Risk of Genital Warts: A Danish Nationwide Population-based Study

BACKGROUND

Increasing evidence suggests that 1-dose human papillomavirus (HPV) vaccination may protect significantly against HPV-related disease. We provide nationwide, real-world data on the risk of genital warts (GWs) after <3 vaccine doses.

METHODS

All Danish women born in 1985-2003 were identified, and individual-level vaccination data were retrieved. The cohort was followed up for first occurrence of GWs until 31 December 2016. Using Poisson regression, we calculated incidence rates (IRs) of GWs per 100 000 person-years and IR ratios (IRRs) with corresponding 95% confidence intervals (CIs) for GWs, according to vaccination status, age at first dose, and calendar time.

RESULTS

The cohort comprised 1 076 945 girls and women, of whom 485 408 were vaccinated. For girls initiating vaccination at age 12-14 years and 15-16 years, 1-dose vaccine effectiveness (VE) was 71% (IRR = 0.29; 95% CI, .22-.38) and 62% (0.38; .29-.49), respectively, compared with unvaccinated girls. In the same age groups, 2-dose VE was 78% (IRR, 0.22; 95% CI, .18-.26) and 68% (0.32; .26-.38), respectively. After 2009, the IRRs for 3 versus 1 dose and 2 versus 1 dose increased towards unity over calendar time, being 0.69 (95% CI, .57-.84) and 0.86 (.68-1.08) in 2016, respectively.

CONCLUSIONS

In this study, 1 or 2 doses of quadrivalent HPV vaccine was associated with substantial protection against GWs in girls vaccinated at age ≤16 years. The 1-dose VE approached that of 3 or 2 doses over calendar time, probably reflecting the impact of herd protection.

Evaluation of Durability of a Single Dose of the Bivalent HPV Vaccine: The CVT Trial

BACKGROUND

The authors investigated the durability of vaccine efficacy (VE) against human papillomavirus (HPV)16 or 18 infections and antibody response among nonrandomly assigned women who received a single dose of the bivalent HPV vaccine compared with women who received multiple doses and unvaccinated women.

METHODS

HPV infections were compared between HPV16 or 18-vaccinated women aged 18 to 25 years who received one (N = 112), two (N = 62), or three (N = 1365) doses, and age- and geography-matched unvaccinated women (N = 1783) in the long-term follow-up of the Costa Rica HPV Vaccine Trial. Cervical HPV infections were measured at two study visits, approximately 9 and 11 years after initial HPV vaccination, using National Cancer Institute next-generation sequencing TypeSeq1 assay. VE and 95% confidence intervals (CIs) were estimated. HPV16 or 18 antibody levels were measured in all one- and two-dose women, and a subset of three-dose women, using a virus-like particle-based enzyme-linked immunosorbent assay (n = 448).

RESULTS

Median follow-up for the HPV-vaccinated group was 11.3 years (interquartile range = 10.9-11.7 years) and did not vary by dose group. VE against prevalent HPV16 or 18 infection was 80.2% (95% CI = 70.7% to 87.0%) among three-dose, 83.8% (95% CI = 19.5% to 99.2%) among two-dose, and 82.1% (95% CI = 40.2% to 97.0%) among single-dose women. HPV16 or 18 antibody levels did not qualitatively decline between years four and 11 regardless of the number of doses given, although one-dose titers continue to be statistically significantly lower compared with two- and three-dose titers.

CONCLUSION

More than a decade after HPV vaccination, single-dose VE against HPV16 or 18 infection remained high and HPV16 or 18 antibodies remained stable. A single dose of bivalent HPV vaccine may induce sufficiently durable protection that obviates the need for more doses.

Single-dose nonavalent HPV vaccine: Need of the hour

Human Papilloma Virus (HPV) vaccination of the preadolescent (9-14 years) females is the potential solution to eradicate carcinoma cervix. Nonavalent vaccine provides wider coverage than the quadrivalent vaccine. On long-term follow-up, even after single-dose HPV vaccination, the antibody titer remains good. Herd immunity can also be achieved by HPV vaccination. Hence, mass single-dose nonavalent HPV vaccination for sexually naive preadolescent girls can provide almost 100% protections and a cost-effective approach for the developing countries.

Evaluation of serological assays to monitor antibody responses to single-dose HPV vaccines

INTRODUCTION

Whether existing serological assays are sufficiently robust to measure the lower antibody levels expected following single-dose HPV vaccination is unknown.

METHODS

We evaluated seven assays measuring HPV-16/18 immunological responses overall and by number of doses in 530 serum samples from participants receiving varying doses of Cervarix or Gardasil up to 36-months post-vaccination. Serum was evaluated by simplex (HPV-16 ELISA, HPV-18 ELISA), multiplex (LIA-4, VLP-MIA, M9ELISA, GST-L1), and high-throughput pseudovirion-based neutralization assays (HT-PBNA), and results were compared to the gold standard HPV-16/18 secreted alkaline phosphatase neutralization assay (SEAP-NA). Reproducibility was assessed by the coefficient of variation (CV) and intraclass correlation coefficient (ICC). Percent agreement, Pearson correlation, and weighted-kappa were used to assess validity. Determinants of seronegativity were evaluated by chi-squared test.

RESULTS

HPV-16: Seropositivity range was 97.1-99.5% for single dose and 98.8-99.8% overall. CV range was 4.0-18.0% for single dose and 2.9-19.5% overall. ICC range was 0.77-0.99 for single dose and 0.74-0.99 overall. Correlation with SEAP-NA range was 0.43-0.85 for single dose and 0.51-0.90 overall. Weighted-kappa range was 0.34-0.82 for single dose and 0.45-0.84 overall. HPV-18: Seropositivity range was 63.9-94.7% for single dose and 86.2-97.9% overall. CV range was 8.1-18.2% for single dose and 4.6-18.6% overall. ICC range was 0.75-0.99 for single dose and 0.83-0.99 overall. Correlation with SEAP-NA range was 0.31-0.99 for single dose and 0.27-0.96 overall. Weighted-kappa range was 0.35-0.83 for single dose and 0.45-0.84 overall. HPV-16 seronegativity was <5% for all assays. HPV-18 seronegativity range was 5.5-17.3%. For LIA-4 and GST-L1 where the proportion of seronegativity was >10%, the strongest correlates of seronegativity were receiving a single vaccine dose and receiving Gardasil.

CONCLUSIONS

These results support the utility of existing serological assays to monitor antibody responses following single-dose HPV vaccination.

Elicitation of potent neutralizing antibody responses by designed protein nanoparticle vaccines for SARS-CoV-2

A safe, effective, and scalable vaccine is urgently needed to halt the ongoing SARS-CoV-2 pandemic. Here, we describe the structure-based design of self-assembling protein nanoparticle immunogens that elicit potent and protective antibody responses against SARS-CoV-2 in mice. The nanoparticle vaccines display 60 copies of the SARS-CoV-2 spike (S) glycoprotein receptor-binding domain (RBD) in a highly immunogenic array and induce neutralizing antibody titers roughly ten-fold higher than the prefusion-stabilized S ectodomain trimer despite a more than five-fold lower dose. Antibodies elicited by the nanoparticle immunogens target multiple distinct epitopes on the RBD, suggesting that they may not be easily susceptible to escape mutations, and exhibit a significantly lower binding:neutralizing ratio than convalescent human sera, which may minimize the risk of vaccine-associated enhanced respiratory disease. The high yield and stability of the protein components and assembled nanoparticles, especially compared to the SARS-CoV-2 prefusion-stabilized S trimer, suggest that manufacture of the nanoparticle vaccines will be highly scalable. These results highlight the utility of robust antigen display platforms for inducing potent neutralizing antibody responses and have launched cGMP manufacturing efforts to advance the lead RBD nanoparticle vaccine into the clinic.