Impacts of human papillomavirus vaccination for different populations: A modeling study

Scientific approaches toward improving cervical cancer elimination strategies

At the 2023 EUROGIN workshop scientific basis for strategies to accelerate the elimination of cervical cancer and its causative agent, human papillomavirus (HPV) were reviewed. Although some countries have reached key performance indicators toward elimination (>90% of girls HPV vaccinated and >70% of women HPV screened), most are yet to reach these targets, implying a need for improved strategies. Gender-neutral vaccination, even with moderate vaccination coverage was highlighted as a strategy to achieve elimination more rapidly. It is more resilient against major disturbances in vaccination delivery, such as what happened during the coronavirus pandemic. Further, an analysis of ethical/legal issues indicated that female-restricted vaccination is problematic. Extended catch-up of vaccination with concomitant screening, and outreach to vulnerable groups were highlighted. Although birth cohorts with high coverage of HPV vaccination at school are protected against HPV, and HPVs have a very low reproductive rate in women above age 35, adult women below age 30 have inadequate direct protection. In addition to herd protection from gender-neutral vaccination, this group can be protected by offering concomitant catch-up HPV vaccination and HPV screening. Furthermore, hepatitis B vaccination experiences indicate that elimination cannot be achieved without prioritizing vulnerable/migrant populations. The long-lasting durability of vaccination-induced antibody responses suggests prolonged protection with HPV vaccines when adequately administrated. Finally, cost-effectiveness modelling suggests that high-coverage HPV vaccination in multiple population segments will be resource-saving due to reduced need for screening. In summary, the workshop found that strategically optimal deployment of vaccination will accelerate elimination of HPV and cervical cancer.

Building resilient cervical cancer prevention through gender-neutral HPV vaccination

The COVID-19 pandemic has disrupted HPV vaccination programmes worldwide. Using an agent-based model, EpiMetHeos, recently calibrated to Indian data, we illustrate how shifting from a girls-only (GO) to a gender-neutral (GN) vaccination strategy could improve the resilience of cervical cancer prevention against disruption of HPV vaccination. In the base case of 5-year disruption with no coverage, shifting from GO to GN strategy under 60% coverage (before disruption) would increase the resilience, in terms of cervical cancer cases still prevented in the disrupted birth cohorts per 100,000 girls born, by 2.8-fold from 107 to 302 cases, and by 2.2-fold from 209 to 464 cases under 90% coverage. Furthermore, shifting to GN vaccination helped in reaching the World Health Organization (WHO) elimination threshold. Under GO vaccination with 60% coverage, the age-standardised incidence rate of cervical cancer in India in the long term with vaccination decreased from 11.0 to 4.7 cases per 100,000 woman-years (above threshold), as compared to 2.8 cases (below threshold) under GN with 60% coverage and 2.4 cases (below threshold) under GN with 90% coverage. In conclusion, GN HPV vaccination is an effective strategy to improve the resilience to disruption of cancer prevention programmes and to enhance the progress towards cervical cancer elimination.

Population Impact of Girls-Only Human Papillomavirus 16/18 Vaccination in The Netherlands: Cross-Protective and Second-Order Herd Effects

Background

Human papillomavirus (HPV) vaccination programs achieve substantial population-level impact, with effects extending beyond protection of vaccinated individuals. We assessed trends in HPV prevalence up to 8 years postvaccination among men and women in the Netherlands, where bivalent HPV vaccination, targeting HPV types 16/18, has been offered to (pre)adolescent girls since 2009 with moderate vaccination coverage.

Methods

We used data from the PASSYON study, a survey initiated in 2009 (prevaccination) and repeated biennially among 16- to 24-year-old visitors of sexual health centers. We studied genital HPV positivity from 2009 to 2017 among women, heterosexual men, and unvaccinated women using Poisson generalized estimating equation models, adjusted for individual- and population-level confounders. Trends were studied for 25 HPV types detected by the SPF10-LiPA25 platform.

Results

A total of 6354 women (64.7% self-reported unvaccinated) and 2414 heterosexual men were included. Percentual declines in vaccine types HPV-16/18 were observed for all women (12.6% per year [95% confidence interval {CI}, 10.6–14.5]), heterosexual men (13.0% per year [95% CI, 8.3–17.5]), and unvaccinated women (5.4% per year [95% CI, 2.9–7.8]). We observed significant declines in HPV-31 (all women and heterosexual men), HPV-45 (all women), and in all high-risk HPV types pooled (all women and heterosexual men). Significant increases were observed for HPV-56 (all women) and HPV-52 (unvaccinated women).

Conclusions

Our results provide evidence for first-order herd effects among heterosexual men against HPV-16/18 and cross-protective types. Additionally, we show second-order herd effects against vaccine types among unvaccinated women. These results are promising regarding population-level and clinical impact of girls-only bivalent HPV vaccination in a country with moderate vaccine uptake.

Surveillance systems for monitoring cervical cancer elimination efforts: Focus on HPV infection, cervical dysplasia, cervical screening and treatment

In order to achieve the global elimination of cervical cancer as a public health problem, close surveillance of progress in public health and clinical activities and outcomes across the three pillars of vaccination, screening and treatment will be required. Surveillance should ideally occur within an integrated system that is planned, funded, and regularly evaluated to ensure it is providing timely, accurate and relevant feedback for action. In this paper, we conceptualise the main public health surveillance objectives as process and outcome measures in each of the three pillars. Process measures include coverage/participation measures for vaccination, screening and treatment alongside the ongoing assessment of the quality and reach of these programs and activities. Outcome measures related to the natural history of human papillomavirus (HPV) infection include HPV infection prevalence, precursor cervical lesions and cervical cancers (including stage at diagnosis, cancer incidence and mortality). These outcome measures can be used for monitoring the effectiveness of the three core activities in the short, medium and long term to assess whether these interventions are effectively reducing their occurrence. We discuss possible methods for the surveillance of these measures in the context of country capacity, drawing from examples in Australia, the USA and in low and middle income countries.

Vaccination against HPV: boosting coverage and tackling misinformation

The availability of human papillomavirus (HPV) vaccines and screening tests has raised the possibility of globally eliminating cervical cancer, which is caused by HPV. Cervical cancer is a very common malignancy worldwide, especially among deprived women. High vaccination coverage is key to the containment and eventual elimination of the infection. Public HPV vaccination programmes in Italy and Denmark were swiftly established and are among the most successful worldwide. Still, in both countries, it has been challenging to achieve and maintain the recommended coverage of > 80% in girls. In a well-studied Italian region, vaccination coverage in girls at age 15 years (World Health Organization's gold standard) reached 76% in 2015 but decreased to 69% in 2018, likely due to work overload in public immunization centres. In Denmark, doubts about safety and efficacy of the HPV vaccine generated a decline in coverage among girls age 12-17, from 80% in 2013 down to 37% in 2015, when remedial actions made it rise again. Insights from these two countries are shared to illustrate the importance of monitoring coverage in a digital vaccine registry and promptly reacting to misinformation about vaccination.

Ambulatory anal self-sampling in MSM living with HIV, an acceptable and reliable screening method

Objectives

Anal cancer, usually driven by an oncogenic Human Papillomavirus, remains a leading cause of morbidity in men who have sex with men (MSM) living with HIV, despite combined antiretroviral therapy. Various recommendations advocate to perform regular examination and proctologist-performed samples to anticipate this risk and treat locally before cancer occurrence, an efficient strategy which has the drawback of requiring the proctologist’s availability. This study evaluates the acceptability, feasibility, and efficiency of self-performed samples to screen for HPV-infection and HPV-related anal dysplasia among MSM living with HIV followed in Hôtel-Dieu Hospital.

Methods

Between February 2015 and June 2015, MSM living with HIV and referred to the day-care hospital were offered to perform an anal self-sampling for cytologic and virologic evaluation. A self-sampling kit was provided, and a tutorial video was shown. A subset of participants had a proctology appointment after they did the self-sampling, and thus had a clinical examination and an anal swab sampling performed by the proctologist, using the same sampling material.

Results

Anal self-sampling was offered to 103 patients, and 100 accepted. Sixty-three samples were interpretable, of which 36 (57%) were normal and 27 (43%) showed abnormal results. Virologic analysis was performed for 60 (95%) interpretable samples: 50/60 (83%) of them were positive for HPV. Among HPV-carrier patients, 42/50 (84%) were infected with at least one HR-HPV. Twenty patients had a proctologist consultation. All clinician-performed samples were interpretable and 14 (70%) self-samples were interpretable.

Conclusions

This study highlights the acceptable accuracy of self-sampling screening method among MSM living with HIV and try out its acceptability and feasibility as a secondary prevention device. Although it cannot replace a proctologist consultation for high risk patients, self-sampling should be studied further as one of the ways of screening for anal cancer among low-risk outpatients.

FACTORS ASSOCIATED WITH ADOLESCENT COMPLIANCE WITH HUMAN PAPILLOMAVIRUS VACCINE: A CROSS-SECTIONAL STUDY

ABSTRACT Objective: to identify the factors associated with adolescent compliance with the human papillomavirus vaccine. Method: this is a cross-sectional study, developed through a school survey, in Teresina, Piauí, Brazil, whose data collection occurred in 2018. A scale was used to assess decision-making, attitudes, feelings and knowledge about the human papillomavirus, in addition to a questionnaire to collect sociodemographic, economic and vaccination status data. The variables were submitted to the multivariate model of logistic regression to explain factors associated with vaccination adeforemen. Results: the study sample consisted of 624 adolescents, 15 years old, attending the first year of high school, of which 22.8% received the human papillomavirus vaccine. Being male decreases the chance of complying with the vaccine by 50% (aOR=0.05). Moreover, disagreeing or disagreeing with or disagreeing with parents to make the decision to vaccinate their children also reduced the chances of vaccination by 66% (aOR=0.34), respectively, as well as disagreeing with or disagreeing that men do not take human papillomavirus, minimized the chances of vaccination complying with vaccination by 66% (aOR=0.34), when compared to those who disagreed with this statement. Conclusion: low adolescent compliance with human papillomavirus vaccine was identified. Adolescents remain susceptible to diseases related to the human papillomavirus. Therefore, vaccination strategies need to be rethought, with the offer of vaccination in schools, mediated by educational campaigns.

Assessing the Long-Term Role of Vaccination against HPV after Loop Electrosurgical Excision Procedure (LEEP): A Propensity-Score Matched Comparison

Background: Primary prevention through vaccination is a prophylactic approach aiming to reduce the risk of developing human papillomavirus (HPV)-related lesions. No mature and long-term data supported the adoption of vaccination in women undergoing conization. Methods: This is a retrospective multi-institutional study. Charts of consecutive patients undergoing conization between 2010 and 2014 were collected. All patients included had at least 5 years of follow-up. We compared outcomes of patients undergoing conization plus vaccination and conization alone. A propensity-score matching algorithm was applied in order to reduce allocation biases. The risk of developing recurrence was estimated using Kaplan-Meir and Cox hazard models. Results: Overall, charts of 1914 women were analyzed. The study group included 116 (6.1%) and 1798 (93.9%) women undergoing conization plus vaccination and conization alone, respectively. Five-year recurrence rate was 1.7% (n = 2) and 5.7% (n = 102) after conization plus vaccination and conization alone, respectively (p = 0.068). After the application of a propensity-score matching, we selected 100 patients undergoing conization plus vaccination and 200 patients undergoing conization alone. The crude number of recurrences was 2 (2%) and 11 (5.5%) for patients undergoing conization plus vaccination and conization alone, respectively (p = 0.231). Vaccination had no impact on persistent lesions (no negative examination between conization and new cervical dysplasia; p = 0.603), but reduced the risk of recurrent disease (patients who had at least one negative examination between conization and the diagnosis of recurrent cervical dysplasia; p = 0.031). Conclusions: Patients having vaccination experience a slightly lower risk of recurrence than women who had not, although not statistically significantly different. Further evidence is needed to assess the cost effectiveness of adopting vaccination in this setting.

Universal Human Papillomavirus Vaccination and its Impact on the Southern Italian Region

HPV is still the most common sexually transmitted infection, leading to the onset of many disorders while causing an increase in direct and indirect health costs. High Risk (HR) HPV is the primary cause of invasive cervical cancer and contributes significantly to the development of anogenital and oropharyngeal cancers. The introduction of universal HPV vaccination has led to a significant reduction in vaccine-targeted HPV infections, cross-protective genotypes, precancerous lesions and anogenital warts. Despite the several limitations of HPV vaccination programs, including vaccine type specificity, different schedules, target age-groups and poor communication, the impact has become increasingly evident, especially in countries with high vaccine uptake. We carried out a review of the most recent literature to evaluate the effects of HPV vaccination on vaccinetargeted HPV genotypes and to assess the level of cross-protection provided against non-vaccine HPV types. Subsequently, to assess the rates of HPV infection in a southeast Italian region, we performed an epidemiological investigation on the impact of vaccination on genotypes and on the prevalence and distribution of HPV infection during the twelve-year period 2006-2017 in the Local Health Unit (LHU) of Lecce. The vaccination coverage of about 70% among girls in the LHU led to an initial reduction in vaccine-targeted HPV types and cross-protective genotypes. However, the results on this population should be interpreted cautiously because the period since the start of vaccination is too short and the coverage rate is not yet optimal to evaluate the efficacy of vaccination in lowering the prevalence of non-vaccine HR HPV types in the vaccinated cohort and in older subjects. Nevertheless, it is expected that direct effects will increase further and that herd immunity will begin to emerge as vaccination coverage increases.

Human papillomavirus vaccine coverage in Rwanda: A population-level analysis by birth cohort

BACKGROUND

In 2011, Rwanda became the first African nation to implement a national human papillomavirus (HPV) vaccination program, conceived to protect girls aged <15 years (i.e. born ≥1997). After an initial school-grade-targeted catch-up campaign, there was a transition to routine vaccination of 12 year-olds only. We aimed to produce population-level vaccine coverage estimates.

METHODS

The Rwandan Expanded Program on Immunization (EPI) collected data on number of eligible girls and HPV vaccines delivered, stratified by calendar year (2011-2018), girl's age, district and vaccination round. HPV vaccine coverage was estimated by birth cohort (reconstituted using calendar year and age), as a proportion of (1) eligible target, and (2) the 2012 Rwandan census population.

RESULTS

1,156,863 girls received first dose of HPV vaccine between 2011 and 2018, corresponding to 98% of the eligible target. Median vaccination age was 15 years (interquartile range [IQR] 13-16) in 2011-2013 (school grade-targeted catch-up), 13 years (IQR 12-14) in 2014 (transition) and 12 years in 2015-2018 (routine). Population-level coverage versus the census increased from 10 to 40% for girls born in 1993-1995 (median vaccination age = 17 years) to 50-65% for 1996-2000 birth cohorts (14 years), and 80-90% for 2001-2006 birth cohorts (12 years). Coverage trends were similar across provinces and in the capital, Kigali. Second and third round coverage suggested most vaccinated girls completed their recommended dosing regimen (which reduced from 3 to 2 doses in 2015).

CONCLUSIONS

Birth cohorts provide a clear picture of population-level HPV vaccine coverage after a pragmatic catch-up campaign, particularly in Rwanda where eligible school grades included wide age ranges. Whilst the catch-up campaign resulted in some coverage gaps in out-of-school teenagers, coverage remains high in cohorts routinely targeted as 12 year-olds.

Current status of human papillomavirus vaccination in India's cervical cancer prevention efforts

Efforts are being made to scale up human papillomavirus (HPV) vaccination for adolescent girls in India. Bivalent and quadrivalent HPV vaccines were licensed in the country in 2008, and a nonavalent vaccine was licensed in 2018. Demonstration projects initiated in Andhra Pradesh and Gujarat in 2009 introduced HPV vaccination in public health services in India. Following a few deaths in these projects, although subsequently deemed unrelated to vaccination, HPV vaccination in research projects was suspended. This suspension by default resulted in some participants in a trial evaluating two versus three doses receiving only one dose. Since 2016, the successful introduction of HPV vaccination in immunisation programmes in Punjab and Sikkim (with high coverage and safety), government-sponsored opportunistic vaccination in Delhi, prospects of a single dose providing protection, and future availability of an affordable Indian vaccine shows promise for future widespread implementation and evaluation of HPV vaccination in India.

Prevalence of HPV Genotypes in South Europe: Comparisons between an Italian and a Turkish Unvaccinated Population

The human papilloma virus (HPV) is a DNA virus associated with benign and malignant lesions of skin and mucous membranes and is the most common sexually transmitted viral infection worldwide. We investigated the prevalence of HPV infection and associated risk factors in Italian and Turkish women population attending the gynecology outpatients clinic in Naples (Italy) and Pamukkale (Turkey). Women were enrolled from the Department of Obstetrics and Gynecology of the University of Campania “Luigi Vanvitelli” in Naples (Italy) and of “Pamukkale University” in Denizli (Turkey) between January 2014 and June 2015. A questionnaire that included sociodemographic and sexual behavior characteristics, questions about HPV awareness, vaccine status, and reasons for not wanting to get vaccinated, and HPV-related knowledge was completed for each participant, and cervical cytology samples were collected. The prevalence of HPV infection was higher in the Italian group (52.6% vs 32.6%, p < 0.001), while the distribution of genotypes is similar (p=0.325). Moreover, the differences in cytological alterations in these patients are significant (p < 0.001). The analysis showed a higher prevalence of sexual behavioral characteristics (p < 0.001) and better attention to the execution of the screening test in the Italian population (p < 0.001). Italian women showed more knowledge and propensity to vaccination compared to Turkish women (p < 0.001). Our data highlighted three relevant aspects: the different prevalence of cytological abnormalities, the different distribution of risk factors and, above all, the different attitude of women towards the primary prevention of cervical cancer between an Italian and a Turkish population group.

Eradication of human papillomavirus and elimination of HPV-related diseases - scientific basis for global public health policies

INTRODUCTION

Infections with oncogenic human papillomaviruses (HPV) globally cause about 9% of cancers in females and 1% of cancers in males. HPV disease burden can be effectively controlled by prophylactic HPV-vaccination provided it has high impact.

AREAS COVERED

A unique series of biobank-based and health registry-based studies that exploit randomized intervention cohorts has provided data on population-level safety of HPV vaccination, duration of vaccine-induced protection and impact of gender-neutral HPV vaccination, providing a scientific basis for policies to eradicate oncogenic HPV types and associated diseases worldwide.

EXPERT COMMENTARY

The ultimate goal of HPV vaccination is the eradication of high-risk (hr) HPVs. Seventy-five percent coverage gender-neutral vaccination of early adolescents will rapidly eradicate also HPV16 from the general population.

Assessment of herd effects among women and heterosexual men after girls-only HPV16/18 vaccination in the Netherlands: A repeated cross-sectional study

Data on the impact of human papillomavirus (HPV) vaccination on the population HPV prevalence are largely obtained from women. We assessed the impact of the girls‐only HPV16/18 vaccination program in the Netherlands that started in 2009, on trends in HPV prevalence among women and heterosexual men, using data from the PASSYON study. In this cross‐sectional study, the HPV prevalence among 16‐ to 24‐year‐old visitors to sexually transmitted infection clinics was assessed in 2009, 2011, 2013, and 2015. We compared the genital postvaccination HPV prevalence with the prevaccination prevalence (2009) using Poisson GEE models. In total, we included 4,996 women and 1,901 heterosexual men. The percentage of women who reported to be vaccinated increased from 2.3% in 2009 to 37% in 2015. Among all women, the HPV16/18 prevalence decreased from 23% prevaccination to 15% in 2015 (adjusted prevalence ratio [aPR] 0.62, p_trend < 0.01). Among heterosexual men, the HPV16/18 prevalence decreased from 17% prevaccination to 11% in 2015 (aPR 0.52, p_trend < 0.01). Of the heterosexual men with a steady partner, HPV16/18 prevalence was lower among those whose steady partner had been vaccine‐eligible in the national immunization program (aPR 0.13). Among unvaccinated women, the HPV16/18 prevalence in 2015 was not different from prevaccination. The decreasing HPV16/18 prevalence among heterosexual men and the reduced HPV16/18 prevalence among heterosexual men with a vaccine‐eligible steady partner strongly suggests herd protection from girls‐only vaccination. Absence of notable herd effects among unvaccinated women 6 years postvaccination may be due to the moderate vaccine uptake among girls in the Netherlands.

What's new?

Human papillomavirus (HPV) is a sexually transmitted virus that plays a causal role in the development of anogenital and oropharyngeal cancers in both men and women. The population‐level impact of HPV vaccination programs on the HPV prevalence has however mainly been studied in women. This study shows decreasing trends in the HPV16 and HPV18 prevalence among both women and heterosexual men after the introduction of a girls‐only HPV16/18 vaccination program in the Netherlands. The findings provide compelling evidence for herd protection in men. Because HPV16/18 are the most oncogenic types, HPV‐related cancers are expected to decline in both sexes after girls‐only HPV vaccination.

HPV vaccination coverage in the federal state of Belgium according to regions and their impact

Long-term results of the HPV vaccination programs in Australia and Scotland have shown a tremendous impact on the reduction of HPV infection rates and precancerous diseases. Both countries started mass vaccination ten years (Australia) and eight years (Scotland) ago and achieved a vaccination coverage of more than 80 %. Within 20 to 30 years a reduction in cervical cancer by more than 75 % is expected. Furthermore, there will be a reduction in other HPV related cancers like vaginal, vulva, perineal, anal and oropharyngeal cancers. In order to be successful, a high vaccination coverage is needed. In Belgium, the vaccination was introduced in 2010 in the Flemish community and in 2011 in the French community. In the first vaccinated cohorts the coverage in Flemish and French Communities was respectively 84% (2010) and 29% (2012-2013). The latest data suggest that the Flemish Community (Flanders Region) attained a coverage of 91 % while the French Community (Walloon Region) attained a coverage of around 36 %. The regional difference in coverage offers a real-life case. The worst-case scenario could end up with proportionally one half of country having more HPV related cancers than the other half. Currently efforts are performed to increase the coverage rates in both regions and consequently decreasing this difference. Additionally, the updated recommendations regarding the HPV vaccination by the Belgian NITAG (National Immunization Technical Advisory Group) stated that the HPV vaccination should be gender neutral. This could stimulate the vaccination program and increase the coverage. The coverage rate in Flanders is among the highest in the world and the rate in the French Community is increasing. Efforts should be continued in order to maintain trust and increase the coverage rate.