Comparative cost-effectiveness of the quadrivalent and bivalent human papillomavirus vaccines: a transmission-dynamic modeling study

Modelling epidemiological and economics processes - the case of cervical cancer

Different types of mathematical models can be used to forecast the development of diseases as well as associated costs and analyse the cost-effectiveness of interventions. The set of models available to assess these parameters, reach from simple independent equations to highly complex agent-based simulations. For many diseases, it is simple to distinguish between infectious diseases and chronic-degenerative diseases. For infectious diseases, dynamic models are most appropriate because they allow for feedback from the number of infected to the number of new infections, while for the latter Markov models are more appropriate since this feedback is not required. However, for some diseases, the aforementioned distinction is not as clear. Cervical cancer, for instance, is caused by a sexually transmitted virus, and therefore falls under the definition of an infectious disease. However, once infected, the condition can progress to a chronic disease. Consequently, cervical cancer could be considered an infectious or a chronic-degenerative disease, depending on the stage of infection. In this paper, we will analyse the applicability of different mathematical models for epidemiological and economic processes focusing on cervical cancer. For this purpose, we will present the basic structure of different models. We will then conduct a literature analysis of the mathematical models used to predict the spread of cervical cancer. Based on these findings we will draw conclusions about which models can be used for which purpose and which disease. We conclude that each type of model has its advantages and disadvantages, but the choice of model type often seems arbitrary. In the case of cervical cancer, homogenous Markov models seem appropriate if a cohort of newly infected is followed for a shorter period, for instance, to assess the impact of screening programs. For long-term consequences, such as the impact of a vaccination program, a feedback loop from former infections to the future likelihood of infections is required. This can be done using system dynamics or inhomogeneous Markov models. Discrete event or agent-based simulations can be used in the case of cervical cancer when small cohorts or specific characteristics of individuals are required. However, these models require more effort than Markov or System Dynamics models.

Population-level impact of switching to 1-dose human papillomavirus vaccination in high-income countries: examining uncertainties using mathematical modeling

BACKGROUND

A concern in high-income countries is that switching to 1-dose human papillomavirus (HPV) vaccination could cause a rebound in HPV infection and cervical cancer if 1-dose efficacy or duration were inferior to 2 doses. Using mathematical modeling and up-to-date trial-based data, we projected the population-level effectiveness of switching from 2-dose to 1-dose vaccination under different vaccine efficacy and duration assumptions in high-income countries.

METHODS

We used HPV-ADVISE (Agent-based Dynamic model for VaccInation and Screening Evaluation), a transmission-dynamic model of HPV infection and cervical cancer, varying key model assumptions to identify those with the greatest impact on projections of HPV-16 and cervical cancer incidence over time: 1) 1-dose vaccine efficacy and vaccine duration, 2) mechanisms of vaccine efficacy and duration over time, 3) midadult (>30 years of age) sexual behavior, 4) progression to cervical cancer among midadults, and 5) vaccination coverage and programs.

RESULTS

In high-income countries, 1-dose vaccination would cause no appreciable rebound in HPV-16 infection, except for a limited rebound under the most pessimistic assumptions of vaccine duration (average, 25 years), because 1) the switch would occur when HPV prevalence is low because of high 2-dose vaccination coverage and 2) individuals would be protected during their peak ages of sexual activity (<35 to 40 years of age). Our model projects a more limited rebound in cervical cancer because of a shift to older age at infection, resulting in fewer life-years left to potentially develop cancer. Projections were robust when varying key model assumptions.

CONCLUSIONS

High protection during peak ages of sexual activity in high-income countries would likely mitigate any potential rebounds in HPV infection and cervical cancer under the most pessimistic assumptions of 1-dose efficacy and duration.

Gender-Neutral HPV Vaccine in India; Requisite for a Healthy Community: A Review

Human papillomavirus (HPV) affects approximately 80% of individuals, irrespective of gender, and is implicated in various cancers. Existing HPV vaccines, while safe and effective, do not sufficiently protect males when administered solely to females. This review, triggered by the urgent need to address this gap and reduce the associated stigma, aims to evaluate the introduction of a gender-neutral HPV vaccine, GARDASIL-9, in India. The primary objective is to assess the necessity and feasibility of incorporating the gender-neutral HPV vaccine into India's national immunization program. This integration is crucial to ensure equitable access for all children and to mitigate the substantial burden of HPV. A literature search was conducted using databases such as Google Scholar, PubMed, government websites, and relevant publications. Keywords included "gender-neutral vaccine", "HPV vaccine", and "Indian population". The central research question guiding this review is: How necessary and feasible is the inclusion of a gender-neutral HPV vaccine in India's national immunization schedule to ensure equitable access for all children and reduce the HPV burden? The review inclusion criteria comprised studies addressing the prevalence of HPV infections, HPV vaccination awareness among both genders, the cost-effectiveness of gender-neutral vaccines, current HPV vaccination status, and future perspectives specific to India. Studies not meeting these criteria were excluded. The review highlights that introducing a gender-neutral HPV vaccine in India is imperative. Including males in vaccination efforts significantly reduces the overall disease burden and helps in reducing the stigma associated with HPV. A comprehensive vaccination program, bolstered by education and awareness campaigns, and its inclusion in the national immunization schedule is essential. This approach ensures equitable access to the vaccine for all children, fostering a healthier community, preventing HPV-related cancers, and enhancing public health outcomes in India.

HPV Vaccination Adherence in Working-Age Men: A Systematic Review and Meta-Analysis

BACKGROUND

Human papillomavirus (HPV) infection is the most common sexually transmitted viral infection in the world. HPV vaccination adherence rates in men are generally lower than in women. The aim of this systematic review and meta-analysis was to assess adherence to HPV vaccination in young working-age males (18-30 years old).

METHODS

A systematic review was performed using three databases: PubMed, Scopus, and Web of Science, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

After duplicate removal, the initial search resulted in 478 eligible papers. With the exclusion of 425 papers after screening the abstracts, full texts of 53 articles were reviewed. Subsequently, 45 were excluded. Among the eight studies included, four (50%) examined the vaccination adherence in young adults through data registered in nationwide insurance or private companies' databases, three (37.5%) in young adults in different settings through data collected from surveys and questionnaires, and one (12.5%) an HPV vaccination campaign in a family medicine residency practice.

CONCLUSION

Adherence to HPV vaccination in men of working age (18-30 years) does not appear to be adequate (pooled prevalence 11%). In order to achieve a higher level of compliance, it is important to place an emphasis on vaccination campaigns in schools as well as in the workplace, after consultation with and approval from local, regional, and federal public health agencies.

Cost-effectiveness of Interventions to Increase HPV Vaccine Uptake

OBJECTIVES

We sought to prioritize interventions for increasing human papillomavirus (HPV) vaccination coverage based on cost-effectiveness from a US state perspective to inform decisions by policy makers.

METHODS

We developed a dynamic simulation model of HPV transmission and progression scaled to a medium-sized US state (5 million individuals). We modeled outcomes over 50 years comparing no intervention to a one-year implementation of centralized reminder and recall for HPV vaccination, school-located HPV vaccination, or quality improvement (QI) visits to primary care clinics. We used probabilistic sensitivity analysis to assess a range of plausible outcomes associated with each intervention. Cost-effectiveness was evaluated relative to a conservative willingness-to-pay threshold; $50 000 per quality-adjusted life-year (QALY) .

RESULTS

All interventions were cost-effective, relative to no intervention. QI visits had the lowest cost and cost per QALY gained ($1538 versus no intervention). Statewide implementation of centralized reminder and recall cost $28 289 per QALY gained versus QI visits. School-located vaccination had the highest cost but was cost-effective at $18 337 per QALY gained versus QI visits. Scaling to the US population, interventions could avert 3000 to 14 000 future HPV cancers. When varying intervention cost and impact over feasible ranges, interventions were typically preferred to no intervention, but cost-effectiveness varied between intervention strategies.

CONCLUSIONS

Three interventions for increasing HPV vaccine coverage were cost-effective and offered substantial health benefits. Policy makers seeking to increase HPV vaccination should, at minimum, dedicate additional funding for QI visits, which are consistently effective at low cost and may additionally consider more resource-intensive interventions (reminder and recall or school-located vaccination).

Human Papillomavirus Vaccination and Physical and Mental Health Complaints Among Female Students in Secondary Education Institutions in Denmark

BACKGROUND

Previous studies have not explored the effect of HPV vaccination on health status at a longer time interval. Similarly, self-reported physical and mental health in recipients of the HPV vaccine has not been studied.

OBJECTIVE

To evaluate whether HPV vaccination was associated with physical and mental health complaints among girls in secondary education institutions.

DESIGN

Prospective cohort study.

PARTICIPANTS

This study used data from girls aged 15-20 years who participated in the Danish National Youth Study (DNYS) 2014. Data on HPV vaccination was retrieved from the Danish Vaccination Register.

MAIN MEASURES

Participants were asked whether they had experienced headaches, stomachache, neck pain, menstrual cramps, sore throat, sadness, irritation, nervousness and sleep problems in the past 6 months.

KEY RESULTS

Of 41,333 girls, 39,145 (94.7%) received at least one dose of HPV vaccine. The most prevalent health complaint among the vaccinated and not vaccinated females was "been irritable" (88.2% and 88.4%, respectively). The lowest proportion of health complaints was stomachache (49.6% in vaccinated and in 50.4% in unvaccinated girls). Regression model, adjusted for socio-demographic characteristics and health behavior, showed that HPV vaccination was associated with a lower likelihood of reporting sore throat (odd ratio [OR] 0.86, 95% confidence interval [CI] 0.78-0.95) and being sad (OR 0.86, 95%CI 0.76-0.97). Similar results were observed when HPV vaccination status was analyzed according to the number of doses received.

CONCLUSION

We conclude that HPV vaccination was not associated with physical and mental health complaints among girls in secondary education institutions in Denmark after a median of 5.3 years since HPV vaccination.

Impact of HPV vaccination and cervical screening on cervical cancer elimination: a comparative modelling analysis in 78 low-income and lower-middle-income countries

BACKGROUND

The WHO Director-General has issued a call for action to eliminate cervical cancer as a public health problem. To help inform global efforts, we modelled potential human papillomavirus (HPV) vaccination and cervical screening scenarios in low-income and lower-middle-income countries (LMICs) to examine the feasibility and timing of elimination at different thresholds, and to estimate the number of cervical cancer cases averted on the path to elimination.

METHODS

The WHO Cervical Cancer Elimination Modelling Consortium (CCEMC), which consists of three independent transmission-dynamic models identified by WHO according to predefined criteria, projected reductions in cervical cancer incidence over time in 78 LMICs for three standardised base-case scenarios: girls-only vaccination; girls-only vaccination and once-lifetime screening; and girls-only vaccination and twice-lifetime screening. Girls were vaccinated at age 9 years (with a catch-up to age 14 years), assuming 90% coverage and 100% lifetime protection against HPV types 16, 18, 31, 33, 45, 52, and 58. Cervical screening involved HPV testing once or twice per lifetime at ages 35 years and 45 years, with uptake increasing from 45% (2023) to 90% (2045 onwards). The elimination thresholds examined were an average age-standardised cervical cancer incidence of four or fewer cases per 100 000 women-years and ten or fewer cases per 100 000 women-years, and an 85% or greater reduction in incidence. Sensitivity analyses were done, varying vaccination and screening strategies and assumptions. We summarised results using the median (range) of model predictions.

FINDINGS

Girls-only HPV vaccination was predicted to reduce the median age-standardised cervical cancer incidence in LMICs from 19·8 (range 19·4-19·8) to 2·1 (2·0-2·6) cases per 100 000 women-years over the next century (89·4% [86·2-90·1] reduction), and to avert 61·0 million (60·5-63·0) cases during this period. Adding twice-lifetime screening reduced the incidence to 0·7 (0·6-1·6) cases per 100 000 women-years (96·7% [91·3-96·7] reduction) and averted an extra 12·1 million (9·5-13·7) cases. Girls-only vaccination was predicted to result in elimination in 60% (58-65) of LMICs based on the threshold of four or fewer cases per 100 000 women-years, in 99% (89-100) of LMICs based on the threshold of ten or fewer cases per 100 000 women-years, and in 87% (37-99) of LMICs based on the 85% or greater reduction threshold. When adding twice-lifetime screening, 100% (71-100) of LMICs reached elimination for all three thresholds. In regions in which all countries can achieve cervical cancer elimination with girls-only vaccination, elimination could occur between 2059 and 2102, depending on the threshold and region. Introducing twice-lifetime screening accelerated elimination by 11-31 years. Long-term vaccine protection was required for elimination.

INTERPRETATION

Predictions were consistent across our three models and suggest that high HPV vaccination coverage of girls can lead to cervical cancer elimination in most LMICs by the end of the century. Screening with high uptake will expedite reductions and will be necessary to eliminate cervical cancer in countries with the highest burden.

FUNDING

WHO, UNDP, UN Population Fund, UNICEF-WHO-World Bank Special Program of Research, Development and Research Training in Human Reproduction, Canadian Institute of Health Research, Fonds de recherche du Québec-Santé, Compute Canada, National Health and Medical Research Council Australia Centre for Research Excellence in Cervical Cancer Control.

Mortality impact of achieving WHO cervical cancer elimination targets: a comparative modelling analysis in 78 low-income and lower-middle-income countries

BACKGROUND

WHO is developing a global strategy towards eliminating cervical cancer as a public health problem, which proposes an elimination threshold of four cases per 100 000 women and includes 2030 triple-intervention coverage targets for scale-up of human papillomavirus (HPV) vaccination to 90%, twice-lifetime cervical screening to 70%, and treatment of pre-invasive lesions and invasive cancer to 90%. We assessed the impact of achieving the 90-70-90 triple-intervention targets on cervical cancer mortality and deaths averted over the next century. We also assessed the potential for the elimination initiative to support target 3.4 of the UN Sustainable Development Goals (SDGs)-a one-third reduction in premature mortality from non-communicable diseases by 2030.

METHODS

The WHO Cervical Cancer Elimination Modelling Consortium (CCEMC) involves three independent, dynamic models of HPV infection, cervical carcinogenesis, screening, and precancer and invasive cancer treatment. Reductions in age-standardised rates of cervical cancer mortality in 78 low-income and lower-middle-income countries (LMICs) were estimated for three core scenarios: girls-only vaccination at age 9 years with catch-up for girls aged 10-14 years; girls-only vaccination plus once-lifetime screening and cancer treatment scale-up; and girls-only vaccination plus twice-lifetime screening and cancer treatment scale-up. Vaccination was assumed to provide 100% lifetime protection against infections with HPV types 16, 18, 31, 33, 45, 52, and 58, and to scale up to 90% coverage in 2020. Cervical screening involved HPV testing at age 35 years, or at ages 35 years and 45 years, with scale-up to 45% coverage by 2023, 70% by 2030, and 90% by 2045, and we assumed that 50% of women with invasive cervical cancer would receive appropriate surgery, radiotherapy, and chemotherapy by 2023, which would increase to 90% by 2030. We summarised results using the median (range) of model predictions.

FINDINGS

In 2020, the estimated cervical cancer mortality rate across all 78 LMICs was 13·2 (range 12·9-14·1) per 100 000 women. Compared to the status quo, by 2030, vaccination alone would have minimal impact on cervical cancer mortality, leading to a 0·1% (0·1-0·5) reduction, but additionally scaling up twice-lifetime screening and cancer treatment would reduce mortality by 34·2% (23·3-37·8), averting 300 000 (300 000-400 000) deaths by 2030 (with similar results for once-lifetime screening). By 2070, scaling up vaccination alone would reduce mortality by 61·7% (61·4-66·1), averting 4·8 million (4·1-4·8) deaths. By 2070, additionally scaling up screening and cancer treatment would reduce mortality by 88·9% (84·0-89·3), averting 13·3 million (13·1-13·6) deaths (with once-lifetime screening), or by 92·3% (88·4-93·0), averting 14·6 million (14·1-14·6) deaths (with twice-lifetime screening). By 2120, vaccination alone would reduce mortality by 89·5% (86·6-89·9), averting 45·8 million (44·7-46·4) deaths. By 2120, additionally scaling up screening and cancer treatment would reduce mortality by 97·9% (95·0-98·0), averting 60·8 million (60·2-61·2) deaths (with once-lifetime screening), or by 98·6% (96·5-98·6), averting 62·6 million (62·1-62·8) deaths (with twice-lifetime screening). With the WHO triple-intervention strategy, over the next 10 years, about half (48% [45-55]) of deaths averted would be in sub-Saharan Africa and almost a third (32% [29-34]) would be in South Asia; over the next 100 years, almost 90% of deaths averted would be in these regions. For premature deaths (age 30-69 years), the WHO triple-intervention strategy would result in rate reductions of 33·9% (24·4-37·9) by 2030, 96·2% (94·3-96·8) by 2070, and 98·6% (96·9-98·8) by 2120.

INTERPRETATION

These findings emphasise the importance of acting immediately on three fronts to scale up vaccination, screening, and treatment for pre-invasive and invasive cervical cancer. In the next 10 years, a one-third reduction in the rate of premature mortality from cervical cancer in LMICs is possible, contributing to the realisation of the 2030 UN SDGs. Over the next century, successful implementation of the WHO elimination strategy would reduce cervical cancer mortality by almost 99% and save more than 62 million women's lives.

FUNDING

WHO, UNDP, UN Population Fund, UNICEF-WHO-World Bank Special Program of Research, Development and Research Training in Human Reproduction, Germany Federal Ministry of Health, National Health and Medical Research Council Australia, Centre for Research Excellence in Cervical Cancer Control, Canadian Institute of Health Research, Compute Canada, and Fonds de recherche du Québec-Santé.

Effectiveness and Cost-Effectiveness of Human Papillomavirus Vaccination Through Age 45 Years in the United States

BACKGROUND

In the United States, the routine age for human papillomavirus (HPV) vaccination is 11 to 12 years, with catch-up vaccination through age 26 years for women and 21 years for men. U.S. vaccination policy on use of the 9-valent HPV vaccine in adult women and men is being reviewed.

OBJECTIVE

To evaluate the added population-level effectiveness and cost-effectiveness of extending the current U.S. HPV vaccination program to women aged 27 to 45 years and men aged 22 to 45 years.

DESIGN

The analysis used HPV-ADVISE (Agent-based Dynamic model for VaccInation and Screening Evaluation), an individual-based transmission dynamic model of HPV infection and associated diseases, calibrated to age-specific U.S. data.

DATA SOURCES

Published data.

TARGET POPULATION

Women aged 27 to 45 years and men aged 22 to 45 years in the United States.

TIME HORIZON

100 years.

PERSPECTIVE

Health care sector.

INTERVENTION

9-valent HPV vaccination.

OUTCOME MEASURES

HPV-associated outcomes prevented and cost-effectiveness ratios.

RESULTS OF BASE-CASE ANALYSIS

The model predicts that the current U.S. HPV vaccination program will reduce the number of diagnoses of anogenital warts and cervical intraepithelial neoplasia of grade 2 or 3 and cases of cervical cancer and noncervical HPV-associated cancer by 82%, 80%, 59%, and 39%, respectively, over 100 years and is cost saving (vs. no vaccination). In contrast, extending vaccination to women and men aged 45 years is predicted to reduce these outcomes by an additional 0.4, 0.4, 0.2, and 0.2 percentage points, respectively. Vaccinating women and men up to age 30, 40, and 45 years is predicted to cost $830 000, $1 843 000, and $1 471 000, respectively, per quality-adjusted life-year gained (vs. current vaccination).

RESULTS OF SENSITIVITY ANALYSIS

Results were most sensitive to assumptions about natural immunity and progression rates after infection, historical vaccination coverage, and vaccine efficacy.

LIMITATION

Uncertainty about the proportion of HPV-associated disease due to infections after age 26 years and about the level of herd effects from the current HPV vaccination program.

CONCLUSION

The current HPV vaccination program is predicted to be cost saving. Extending vaccination to older ages is predicted to produce small additional health benefits and result in substantially higher incremental cost-effectiveness ratios than the current recommendation.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.

Stopping the HPV vaccine crisis in Japan: Quantifying the benefits and risks of HPV vaccination in quality-adjusted life-years for appropriate decision-making

BACKGROUND

The human papilloma virus (HPV) vaccination coverage rate in Japan has dropped dramatically from more than 70% to less than 1% since 2013. With conflicting information and a lack of quantification of the benefits and risks of the HPV vaccine, parents have been hindered in making their decision. We quantified the benefits and risks of the HPV vaccine in terms of quality-adjusted life-years (QALYs), to help their informed decision.

METHOD

A literature search was performed to determine the incidence and burden of each outcome in a decision tree model. The benefits and the risks of the HPV vaccination were determined in QALY change with a sensitivity analysis.

RESULT

The benefits of the HPV vaccine in terms of QALYs gained were 703.72, 14.45, and 30.83/100,000 persons for cervical cancer, cervical intraepithelial neoplasm 3 (CIN 3), and genital warts, respectively. The QALY loss due to acute adverse reactions, chronic adverse reactions without assistance needs, and chronic adverse reactions with assistance needs were 0.07, 5.83, and 5.82/100,000 persons, respectively. The risk/benefit ratio in QALY change in the base case was 0.0156. In all scenarios, the benefit of the HPV vaccine was significantly greater than the risk.

CONCLUSION

The benefits are much greater than the risks, even if it is assumed that all reported adverse events were due to the vaccination. The Japanese government and health care providers should immediately recommend the HPV vaccine to all adolescent girls irrespective of any causal links between the vaccine and reported adverse events.

Assessing the cost-effectiveness of HPV vaccination strategies for adolescent girls and boys in the UK

BACKGROUND

Human papillomavirus (HPV) is the most widespread sexually transmitted infection worldwide. It causes several health consequences, in particular accounting for the majority of cervical cancer cases in women. In the United Kingdom, a vaccination campaign targeting 12-year-old girls started in 2008; this campaign has been successful, with high uptake and reduced HPV prevalence observed in vaccinated cohorts. Recently, attention has focused on vaccinating both sexes, due to HPV-related diseases in males (particularly for high-risk men who have sex with men) and an equity argument over equalising levels of protection.

METHODS

We constructed an epidemiological model for HPV transmission in the UK, accounting for nine of the most common HPV strains. We complemented this with an economic model to determine the likely health outcomes (healthcare costs and quality-adjusted life years) for individuals from the epidemiological model. We then tested vaccination with the three HPV vaccines currently available, vaccinating either girls alone or both sexes. For each strategy we calculated the threshold price per vaccine dose, i.e. the maximum amount paid for the added health benefits of vaccination to be worth the cost of each vaccine dose. We calculated results at 3.5% discounting, and also 1.5%, to consider the long-term health effects of HPV infection.

RESULTS

At 3.5% discounting, continuing to vaccinate girls remains highly cost-effective compared to halting vaccination, with threshold dose prices of £56-£108. Vaccination of girls and boys is less cost-effective (£25-£53). Compared to vaccinating girls only, adding boys to the programme is not cost-effective, with negative threshold prices (-£6 to -£3) due to the costs of administration. All threshold prices increase when using 1.5% discounting, and adding boys becomes cost-effective (£36-£47). These results are contingent on the UK's high vaccine uptake; for lower uptake rates, adding boys (at the same uptake rate) becomes more cost effective.

CONCLUSIONS

Vaccinating girls is extremely cost-effective compared with no vaccination, vaccinating both sexes is less so. Adding boys to an already successful girls-only programme has a low cost-effectiveness, as males have high protection through herd immunity. If future health effects are weighted more heavily, threshold prices increase and vaccination becomes cost-effective.

Bivalent Vaccine Effectiveness Against Type-Specific HPV Positivity: Evidence for Cross-Protection Against Oncogenic Types Among Dutch STI Clinic Visitors

Background

Observational postmarketing studies are important to assess vaccine effectiveness (VE). We estimated VE from the bivalent human papillomavirus (HPV) vaccine against HPV positivity of vaccine and nonvaccine types in a high-risk population.

Methods

We included all vaccine-eligible women from the PASSYON study, a biennial cross-sectional survey in Dutch sexually transmitted infection clinics. Vaginal swabs were analyzed using a polymerase chain reaction-based assay (SPF10-LiPA25) able to detect the 12 high-risk HPV (hrHPV) types 16/18/31/33/35/39/45/51/52/56/58/59. We compared hrHPV positivity between self-reported vaccinated (≥1 dose) and unvaccinated women, and estimated VE by a logistic mixed model.

Results

We included 1087 women of which 53% were hrHPV positive and 60% reported to be vaccinated. The adjusted pooled VE against HPV-16/18 was 89.9% (81.7%-94.4%). Moreover, we calculated significant VE against nonvaccine types HPV-45 (91%), HPV-35 (57%), HPV-31 (50%), and HPV-52 (37%). Among women who were offered vaccination 5/6 years ago, we estimated similar VE against HPV-16/18 (92%) and all hrHPV types (35%) compared to women who were offered vaccination <5 years ago (83% and 33%, respectively).

Conclusion

We demonstrated high VE of the bivalent vaccine against HPV-16/18 and cross-protection against HPV-45/35/31/52. Protection against HPV-16/18 was sustained up to 6 years postvaccination.

Pricing of HPV vaccines in European tender-based settings

BACKGROUND

Vaccine price is one of the most influential parameters in economic evaluations of HPV vaccination programmes. Vaccine tendering is a cost-containment method widely used by national or regional health authorities, but information on tender-based HPV vaccine prices is scarce.

METHODS

Procurement notices and awards for the HPV vaccines, published from January 2007 until January 2018, were systematically retrieved from the online platform for public procurement in Europe. Information was collected from national or regional tenders organized for publicly funded preadolescent vaccination programmes against HPV. The influence of variables on the vaccine price was estimated by means of a mixed-effects model.

FINDINGS

Prices were collected from 178 procurements announced in 15 European countries. The average price per dose for the first-generation HPV vaccines decreased from €101.8 (95% CI 91.3-114) in 2007 to €28.4 (22.6-33.5) in 2017, whereas the average dose price of the 9-valent vaccine in 2016-2017 was €49.1 (38.0-66.8). Unit prices were, respectively, €7.5 (4.4-10.6) and €34.4 (27.4-41.4) higher for the 4-valent and 9-valent vaccines than for the 2-valent vaccine. Contract volume and duration, level of procurement (region or country), per capita GDP and number of offers received had a significant effect on vaccine price.

INTERPRETATION

HPV vaccine procurement is widely used across Europe. The fourfold decrease in the average tender-based prices compared to list prices confirms the potential of tendering as an efficient cost-containment strategy, thereby expanding the indications for cost-effective HPV vaccination to previously ineligible target groups.

Vaccination against HPV virus: a systematic review of economic evaluation studies for developed countries

INTRODUCTION

During the last years, a significant number economic evaluations of HPV vaccination has been published. Given that cost-effectiveness constitutes an essential part of decision-making with regards to the reimbursement of a health technology, the purpose of this study is to provide a supportive tool to decision-makers regarding the economic efficiency of the introduction of HPV vaccination to national immunization programs.

AREAS COVERED

The PubMed database was searched in order to identify cost-effectiveness studies for HPV vaccination. A total of 42 articles were finally retrieved. All retrieved cost-effectiveness ratios (ICERs) were converted in the same currency unit (I$) and then inflated to the same year (2015) in order to facilitate cross-country comparisons.

RESULTS

Overall, vaccination against HPV 6,11,16,18 types appears to have a ICER with mean value of I$25132/QALY, whereas the mean ICER of vaccination against oncogenic HPV 16,18 types is estimated at I$38,253/QALY.

EXPERT COMMENTARY

HPV vaccination would be a cost-effective intervention in the setting of high-income countries and could reduce the incidence of HPV-related diseases.

Cost-effectiveness of sex-neutral HPV-vaccination in Sweden, accounting for herd-immunity and sexual behaviour

INTRODUCTION

The aim was to assess cost-effectiveness of expanding the Swedish HPV-vaccination program to include preadolescent boys, by comparing health-effects and costs of HPV-related disease, with a sex-neutral vaccination program versus only vaccinating girls.

METHODS

We used a dynamic compartmental model to simulate the burden of HPV16/18-related disease in Sweden, accounting for indirect effects of vaccination through herd-immunity. The model accounted for sexual behaviour, such as age preferences and men who have sex with men. The main outcome was number of individuals with HPV-related cancers (cervical, genital, anal and oropharyngeal cancer) and cervical intraepithelial neoplasia (CIN). Costs included in the analysis were those incurred when treating HPV-related cancer and CIN, production losses during sick-leave, and acquisition and administration of vaccine. Health effects were measured as quality-adjusted life years (QALY). The time horizon was set to 100 years, and both effects and costs were discounted by 3% annually. Health effects and costs were accumulated over the time horizon and used to create an incremental cost-effectiveness ratio.

RESULTS

A sex-neutral vaccination program would reduce HPV-related cancer and CIN, both due to direct effects among vaccinated as well as through herd-immunity, further decreasing HPV-related cancer burden annually by around 60 cases among men and women respectively in steady-state. The cost per gained QALY was estimated to 40,000 euro. Applying the procurement price of 2017, sex-neutral vaccination was dominant.

CONCLUSION

Introducing a sex-neutral HPV-vaccination program would be good value for money also in Sweden where there this 80% coverage in the current HPV-vaccination program for preadolescent girls. The cost-effectiveness of a sex-neutral program is highly dependent on the price of the vaccine, the lower the price the more favourable it is to also vaccinate boys.

Prevalence of human papillomavirus by geographical regions, sexual orientation and HIV status in China: a systematic review and meta-analysis

OBJECTIVE

Human papillomavirus (HPV) infection causes multiple cancers in both women and men. In China, both HPV vaccination and cervical cancer screening coverages are low. We aim to investigate the temporal and geographical trends of HPV DNA prevalence in heterosexual men, women, men who have sex with men (MSM) and people living with HIV (PLHIV) in China.

METHODS

We conducted a systematic review, collecting publications in PubMed, Web of Science, China National Knowledge Infrastructure (CNKI) and Wanfang Data from January 2000 to May 2017. A total of 247 studies were selected for this meta-analysis to estimate pooled HPV prevalence, incidence of cervical cancer and risk of infection for subgroups. Meta-regression was applied to identify contributing factors to prevalence heterogeneities.

RESULTS

The national HPV prevalence was 15.6% (95% CI (14.4% to 16.9%)) in women with normal cervical cytology, and Central China had the highest prevalence (20.5% (15.2% to 25.8%)). HPV prevalence in heterosexual men (14.5% (11.3% to 17.7%)) was comparable with that of women (OR=1.09 (0.98 to 1.17)), but HPV prevalence in MSM (59.9% (52.2% to 67.6%)) was significantly higher than that in heterosexual men (OR=8.81 (8.01 to 9.69)). HIV-positive women (45.0% (38.4% to 51.6%)) and HIV-positive MSM (87.5% (82.3% to 90.9%)) had 4.67 (3.61 to 6.03) and 6.46 (5.20 to 8.02) times higher risk of HPV infection than their HIV negative counterparts.

CONCLUSION

HPV infection is prevalent in China, particularly in Central China, in comparison with the global level and neighbouring countries. Targeted HPV vaccination for women, MSM and PLHIV and scale-up of cervical screening for women are priorities in curbing the HPV epidemic in China.

Comparative Cost-Effectiveness Analysis of Two Different Two-Dose Human Papillomavirus Vaccines in Malaysia

Purpose:

To comparatively evaluate the results of a 2-dose human papillomavirus (HPV) vaccination programme with the AS04-adjuvanted HPV16/18 vaccine (AS04-HPV-16/18v) or HPV-6/11/16/18 vaccine (4vHPVv), in addition to cervical cancer (CC) screening, in Malaysia.

Methods:

A lifetime Markov model replicating the natural history of HPV in 13-year-old girls was adapted to Malaysia to assess the impact of vaccination on pre-cancerous lesions, genital warts and CC cases, CC deaths, quality-adjusted life years (QALYs), and costs from the perspective of the Malaysian Ministry of Health. Vaccine effectiveness was based on efficacy and HPV type distribution. Both vaccines were assumed to have equal efficacy against vaccine-type HPV but differed for protection against non-vaccine types. Vaccine price parity was used and health and cost outcomes were discounted at 3%/annum. Sensitivity analyses tested the robustness of the results.

Results:

The model predicted that AS04-HPV-16/18v would result in 361 fewer CC cases and 115 fewer CC deaths than 4vHPVv, whereas 4vHPVv averted 4,241 cases of genital warts over the cohort’s lifetime. Discounted total costs showed savings of 18.50 million Malaysian Ringgits and 246 QALYs in favour of AS04-HPV-16/18v. In one-way sensitivity analyses, the discount rate was the most influential variable for costs and QALYs, but AS04-HPV-16/18v remained dominant throughout. A two-way sensitivity analysis to assess the longevity of cross-protection for both vaccines confirmed the base-case.

Conclusions:

In Malaysia, the use of AS04-HPV-16/18v, in addition to screening, was modelled to be dominant over 4vHPVv, with greater estimated CC benefits and lower costs.

Inclusion of the value of herd immunity in economic evaluations of vaccines. A systematic review of methods used

OBJECTIVE

The objectives of this review were to identify vaccine economic evaluations that include herd immunity and describe the methodological approaches used.

METHODS

We used Kim and Goldie's search strategy from a systematic review (1976-2007) of modelling approaches used in vaccine economic evaluations and additionally searched PubMed/MEDLINE and Embase for 2007-2015. Studies were classified according to modelling approach used. Methods for estimating herd immunity effects were described, in particular for the static models.

RESULTS

We identified 625 economic evaluations of vaccines against human-transmissible diseases from 1976 to 2015. Of these, 172 (28%) included herd immunity. While 4% of studies included herd immunity in 2001, 53% of those published in 2015 did this. Pneumococcal, human papilloma and rotavirus vaccines represented the majority of studies (63%) considering herd immunity. Ninety-five of the 172 studies utilised a static model, 59 applied a dynamic model, eight a hybrid model and ten did not clearly state which method was used. Relatively crude methods and assumptions were used in the majority of the static model studies.

CONCLUSION

The proportion of economic evaluations using a dynamic model has increased in recent years. However, 55% of the included studies used a static model for estimating herd immunity. Values from a static model can only be considered reliable if high quality surveillance data are incorporated into the analysis. Without this, the results are questionable and they should only be included in sensitivity analysis.

Cost-effectiveness of Ovarian Cancer Prevention Strategies

Ovarian cancer remains to be the most lethal of all gynecologic malignancies. There is no effective screening test proven to reduce the mortality associated with this disease. Costs of treating ovarian cancer are substantial and among the highest of all cancer types. Therefore, it is essential to pursue strategies to prevent ovarian cancer that are cost-effective in the context of our health care system. There are 2 subgroups of women for whom ovarian cancer prevention strategies have been evaluated for effectiveness and costs: (1) general population at risk, and (2) BRCA mutation carriers with a high lifetime risk.

Lessons from a decade of individual-based models for infectious disease transmission: a systematic review (2006-2015)

Background

Individual-based models (IBMs) are useful to simulate events subject to stochasticity and/or heterogeneity, and have become well established to model the potential (re)emergence of pathogens (e.g., pandemic influenza, bioterrorism). Individual heterogeneity at the host and pathogen level is increasingly documented to influence transmission of endemic diseases and it is well understood that the final stages of elimination strategies for vaccine-preventable childhood diseases (e.g., polio, measles) are subject to stochasticity. Even so it appears IBMs for both these phenomena are not well established. We review a decade of IBM publications aiming to obtain insights in their advantages, pitfalls and rationale for use and to make recommendations facilitating knowledge transfer within and across disciplines.

Methods

We systematically identified publications in Web of Science and PubMed from 2006-2015 based on title/abstract/keywords screening (and full-text if necessary) to retrieve topics, modeling purposes and general specifications. We extracted detailed modeling features from papers on established vaccine-preventable childhood diseases based on full-text screening.

Results

We identified 698 papers, which applied an IBM for infectious disease transmission, and listed these in a reference database, describing their general characteristics. The diversity of disease-topics and overall publication frequency have increased over time (38 to 115 annual publications from 2006 to 2015). The inclusion of intervention strategies (8 to 52) and economic consequences (1 to 20) are increasing, to the detriment of purely theoretical explorations. Unfortunately, terminology used to describe IBMs is inconsistent and ambiguous. We retrieved 24 studies on a vaccine-preventable childhood disease (covering 7 different diseases), with publication frequency increasing from the first such study published in 2008. IBMs have been useful to explore heterogeneous between- and within-host interactions, but combined applications are still sparse. The amount of missing information on model characteristics and study design is remarkable.

Conclusions

IBMs are suited to combine heterogeneous within- and between-host interactions, which offers many opportunities, especially to analyze targeted interventions for endemic infections. We advocate the exchange of (open-source) platforms and stress the need for consistent “branding”. Using (existing) conventions and reporting protocols would stimulate cross-fertilization between research groups and fields, and ultimately policy making in decades to come.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2699-8) contains supplementary material, which is available to authorized users.

Cost-effectiveness of HPV vaccination in the context of high cervical cancer incidence and low screening coverage

BACKGROUND

Estonia has high cervical cancer incidence and low screening coverage. We modelled the impact of population-based bivalent, quadrivalent or nonavalent HPV vaccination alongside cervical cancer screening.

METHODS

A Markov cohort model of the natural history of HPV infection was used to assess the cost-effectiveness of vaccinating a cohort of 12-year-old girls with bivalent, quadrivalent or nonavalent vaccine in two doses in a national, school-based vaccination programme. The model followed the natural progression of HPV infection into subsequent genital warts (GW); premalignant lesions (CIN1-3); cervical, oropharyngeal, vulvar, vaginal and anal cancer. Vaccine coverage was assumed to be 70%. A time horizon of 88years (up to 100years of age) was used to capture all lifetime vaccination costs and benefits. Costs and utilities were discounted using an annual discount rate of 5%.

RESULTS

Vaccination of 12-year-old girls alongside screening compared to screening alone had an incremental cost-effectiveness ratio (ICER) of €14,007 (bivalent), €14,067 (quadrivalent) and €11,633 (nonavalent) per quality-adjusted life-year (QALY) in the base-case scenario and ranged between €5367-21,711, €5142-21,800 and €4563-18,142, respectively, in sensitivity analysis. The results were most sensitive to changes in discount rate, vaccination regimen, vaccine prices and cervical cancer screening coverage.

CONCLUSION

Vaccination of 12-year-old girls alongside current cervical cancer screening can be considered a cost-effective intervention in Estonia. Adding HPV vaccination to the national immunisation schedule is expected to prevent a considerable number of HPV infections, genital warts, premalignant lesions, HPV related cancers and deaths. Although in our model ICERs varied slightly depending on the vaccine used, they generally fell within the same range. Cost-effectiveness of HPV vaccination was found to be most dependent on vaccine cost and duration of vaccine immunity, but not on the type of vaccine used.

Modelling multi-site transmission of the human papillomavirus and its impact on vaccination effectiveness

OBJECTIVE

Previous HPV models have only included genital transmission, when evidence suggests that transmission between several anatomical sites occurs. We compared model predictions of population-level HPV vaccination effectiveness against genital HPV16 infection in women, using a 1) uni-site (genital site), and a 2) multi-site model (genital and one extragenital site).

METHODS

We developed a uni-site and a multi-site deterministic HPV transmission model, assuming natural immunity was either site-specific or systemic. Both models were calibrated to genital HPV16 prevalence (5%-7.5%), whilst the multi-site model was calibrated to HPV16 prevalence representative of oral (0%-1%) and anal (1%-7.5%) sites. For each model, we identified 2500 parameter sets that fit endemic genital and extragenital prevalences within pre-specified target ranges. In the Base-case analysis, vaccination was girls-only with 40% coverage. Vaccine efficacy was 100% for all sites with lifetime protection. The outcome was the relative reduction in genital HPV16 prevalence among women at post-vaccination equilibrium (RRprev). RRprev was stratified by extragenital prevalence pre-vaccination.

RESULTS

Under assumptions of site-specific immunity, RRprev with the multi-site model was generally greater than with the uni-site model. Differences between the uni-site and multi-site models were greater when transmission from the extragenital site to the genital site was high. Under assumptions of systemic immunity, the multi-site and uni-site models yielded similar RRprev in the scenario without immunity after extragenital infection. In the scenario with systemic immunity after extragenital infection, the multi-site model yielded lower predictions of RRprev than the uni-site model.

CONCLUSIONS

Modelling genital-site only transmission may overestimate vaccination impact if extragenital infections contribute to systemic natural immunity or underestimate vaccination impact if a high proportion of genital infections originate from extragenital infections. Under current understanding of heterosexual HPV transmission and immunity, a substantial bias from using uni-site models in predicting vaccination effectiveness against genital HPV infection is unlikely to occur.

The health-economic studies of HPV vaccination in Southeast Asian countries: a systematic review

INTRODUCTION

The cervical cancer-related burden is an important problem in Southeast Asian (SEA) countries. However, only 3 out of 11 countries implement the comprehensive prevention program. Areas covered: This is a retrospective review from all relevant studies until 2015 from two main databases, MEDLINE/Pubmed and Embase in order to provide an evidence on the health economics of HPV vaccination in the region. Expert commentary: The implementation of HPV vaccination will generate substantial health and economic benefit in SEA countries since the number of cervical cancer cases in this region are generally high. Therefore, a clear recommendation on how HPV vaccination should be implemented in a country, for example on how many doses will be used, how much cost is required or is it a school based- or clinical based-delivery, is critically required.

Economic evaluations of vaccines in Canada: a scoping review

BACKGROUND

This study aims to summarise and describe the evolution of published economic evaluations of vaccines in Canada, thereby outlining the current state of this expanding and meaningful research.

METHODS

Using Arksey and O'Malley's scoping review framework we assembled relevant research from both academic and grey literature. Following abstract and full-text review we identified 60 articles to be included in the final analysis.

RESULTS

We found that since 1988 there has been a steady increase in the number of economic evaluations on vaccines in Canada. Many of these studies focus on the more recently licensed vaccines, such as influenza (16.7%), human papillomavirus (15.0%) and pneumococcal disease (15.0%). Since 2010 economic evaluations of vaccines have shown increased adherence to economic evaluation guidelines (OR = 4.6, CI 1.33, 18.7), suggesting there has been improvement in the consistency and transparency of these studies. However, there remains room for improvement, for instance, we found evidence that studies who stated a conflict of interest are more likely to assert the vaccine of interest was cost-effective (OR = 7.4; CI 1.04, 17.8). Furthermore, most reports use static models that do not consider herd immunity, and only a few evaluate vaccines post-implementation (ex-post) and traveller's vaccinations.

CONCLUSION

Researchers should examine identified research gaps and continue to improve standardization and transparency when reporting to ensure economic evaluations of vaccines best meet the needs of policy-makers, other researchers and the public.

The whole story: a systematic review of economic evaluations of HPV vaccination including non-cervical HPV-associated diseases

INTRODUCTION

Many economic evaluations of HPV vaccination have been published, but most have focused on the prevention of cervical disease as a primary health outcome. The cost-effectiveness of vaccination is likely to be underestimated if not all HPV-associated diseases are taken into account. In this review, we assess the influence of non-cervical HPV-associated diseases on the incremental cost-effectiveness ratio (ICER) of preadolescent HPV vaccination. Areas covered: We systematically searched the literature and identified 18 studies that included non-cervical diseases in the estimates of cost-effectiveness of HPV-vaccination. When taking other HPV-related diseases into account compared to not including such other diseases, the mean ICERs were 2.85 times more favorable for girls only vaccination and 3.89 times for gender neutral vaccination. Expert commentary: Including non-cervical diseases in economic evaluations of HPV vaccination programs makes it more likely that the ICER falls beneath accepted cost-effectiveness thresholds and therefore increases the scope for gender neutral vaccination.

Impact and Cost-effectiveness of 3 Doses of 9-Valent Human Papillomavirus (HPV) Vaccine Among US Females Previously Vaccinated With 4-Valent HPV Vaccine

BACKGROUND

We estimated the potential impact and cost-effectiveness of providing 3-doses of nonavalent human papillomavirus (HPV) vaccine (9vHPV) to females aged 13-18 years who had previously completed a series of quadrivalent HPV vaccine (4vHPV), a strategy we refer to as "additional 9vHPV vaccination."

METHODS

We used 2 distinct models: (1) the simplified model, which is among the most basic of the published dynamic HPV models, and (2) the US HPV-ADVISE model, a complex, stochastic, individual-based transmission-dynamic model.

RESULTS

When assuming no 4vHPV cross-protection, the incremental cost per quality-adjusted life-year (QALY) gained by additional 9vHPV vaccination was $146 200 in the simplified model and $108 200 in the US HPV-ADVISE model ($191 800 when assuming 4vHPV cross-protection). In 1-way sensitivity analyses in the scenario of no 4vHPV cross-protection, the simplified model results ranged from $70 300 to $182 000, and the US HPV-ADVISE model results ranged from $97 600 to $118 900.

CONCLUSIONS

The average cost per QALY gained by additional 9vHPV vaccination exceeded $100 000 in both models. However, the results varied considerably in sensitivity and uncertainty analyses. Additional 9vHPV vaccination is likely not as efficient as many other potential HPV vaccination strategies, such as increasing primary 9vHPV vaccine coverage.

Health and Economic Impact of Switching from a 4-Valent to a 9-Valent HPV Vaccination Program in the United States

BACKGROUND

Randomized clinical trials have shown the 9-valent human papillomavirus (HPV) vaccine to be highly effective against types 31/33/45/52/58 compared with the 4-valent. Evidence on the added health and economic benefit of the 9-valent is required for policy decisions. We compare population-level effectiveness and cost-effectiveness of 9- and 4-valent HPV vaccination in the United States.

METHODS

We used a multitype individual-based transmission-dynamic model of HPV infection and disease (anogenital warts and cervical, anogenital, and oropharyngeal cancers), 3% discount rate, and societal perspective. The model was calibrated to sexual behavior and epidemiologic data from the United States. In our base-case, we assumed 95% vaccine-type efficacy, lifelong protection, and a cost/dose of $145 and $158 for the 4- and 9-valent vaccine, respectively. Predictions are presented using the mean (80% uncertainty interval [UI] = 10(th)-90(th) percentiles) of simulations.

RESULTS

Under base-case assumptions, the 4-valent gender-neutral vaccination program is estimated to cost $5500 (80% UI = 2400-9400) and $7300 (80% UI = 4300-11 000)/quality-adjusted life-year (QALY) gained with and without cross-protection, respectively. Switching to a 9-valent gender-neutral program is estimated to be cost-saving irrespective of cross-protection assumptions. Finally, the incremental cost/QALY gained of switching to a 9-valent gender-neutral program (vs 9-valent girls/4-valent boys) is estimated to be $140 200 (80% UI = 4200->1 million) and $31 100 (80% UI = 2100->1 million) with and without cross-protection, respectively. Results are robust to assumptions about HPV natural history, screening methods, duration of protection, and healthcare costs.

CONCLUSIONS

Switching to a 9-valent gender-neutral HPV vaccination program is likely to be cost-saving if the additional cost/dose of the 9-valent is less than $13. Giving females the 9-valent vaccine provides the majority of benefits of a gender-neutral strategy.

Evaluation of the immunogenicity of the quadrivalent HPV vaccine using 2 versus 3 doses at month 21: An epidemiological surveillance mechanism for alternate vaccination schemes

The cost of HPV vaccines and the need for 3 doses remains a barrier for their inclusion in routine vaccination schedules for girls in low and middle income countries. In a non-inferiority study, we aimed to compare the immunogenicity of a standard 3 doses and a 2 doses schedule. We enrolled 450 participants in an open-label non-randomized clinical trial to evaluate the immunogenicity induced at different ages by the licensed HPV6/11/16/18 quadrivalent vaccine in a 2 doses schedule (0-6 months, n = 150 girls aged 9-10 y) and 3 doses schedule (0, 2, and 6 months; n = 150 girls aged 9-10 y and n=150 women aged 18 to 24 years). To assess the antibody response, blood samples were obtained at Month 7 and 21 after the first vaccination from participants in all study groups. cLIA testing was performed at Merck Research Laboratories. Antibody levels were expressed as milli-Merck units (mMU) per ml. Primary outcome was non-inferiority (95% CI, lower bound >0.5) of the geometric mean titers (GMT) ratios for HPV6, HPV11, HPV16 and HPV18 antibodies 7 and 21 months after the first dose among girls receiving 2 doses compared with young women and girls receiving 3 doses. All vaccinees were seropositive for both HPV16 and HPV18 antibodies at month 7. At month 21, 98.5 and 56.6% of women 18-24 y old were seropositive for HPV16 and 18, respectively. For girls in the three doses group, seropositivity rates were 99.3 and 86.3% for HPV16 and 18, respectively. For girls in the two doses group rates were 99.3 and 70.2% for HPV16 and 18, respectively. The two doses schedule was non-inferior compared to the 3 doses schedule in same-age girls and to the group of adult women after 21 months of the first vaccine dose. Our results are in agreement with similar trials evaluating the immune response of a 2 doses schedule of both HPV vaccines, supporting the recent WHO recommendation as well as the Mexican policy to incorporate the 2 doses schedule for girls aged 9-11 y.

Dissecting the indirect effects caused by vaccines into the basic elements

Vaccination directly protects vaccinated individuals, but it also has the potential for indirectly protecting the unvaccinated in a population (herd protection). Unintended negative consequences such as the re-manifestation of infection, mainly expressed as age shifts, result from vaccination programs as well. We discuss the necessary conditions for achieving optimal herd protection (i.e., high quality vaccine-induced immunity, substantial effect on the force of infection, and appropriate vaccine coverage and distribution), as well as the conditions under which age shifts are likely to occur. We show examples to illustrate these effects. Substantial ambiguity in observing and quantifying these indirect vaccine effects makes accurate evaluation troublesome even though the nature of these outcomes may be critical for accurate assessment of the economic value when decision makers are evaluating a novel vaccine for introduction into a particular region or population group. More investigation is needed to identify and develop successful assessment methodologies for precisely analyzing these outcomes.

Quadrivalent human papillomavirus (types 6, 11, 16, 18) recombinant vaccine (gardasil(®)): a review of its use in the prevention of premalignant anogenital lesions, cervical and anal cancers, and genital warts

Quadrivalent human papillomavirus (HPV) [types 6, 11, 16, 18] recombinant vaccine (Gardasil(®); Silgard(®)) is composed of virus-like particles formed by self-assembly of recombinant L1 capsid protein from each of HPV types 6, 11, 16 and 18. It is indicated for use from the age of 9 years as a two- or three-dose vaccination course over 6 months for the prevention of premalignant anogenital lesions, cervical and anal cancers, and genital warts caused by the vaccine HPV types. In placebo-controlled trials, quadrivalent HPV vaccine provided high-level protection against infection or disease caused by the vaccine HPV types over 2-4 years in females aged 15-45 years who were negative for the vaccine HPV types, and provided a degree of cross-protection against certain non-vaccine HPV types. The vaccine also provided high-level protection against persistent infection, anogenital precancerous lesions and genital warts caused by the vaccine HPV types over 3 years in susceptible males aged 16-26 years. Protection has been demonstrated for up to 8 years. In subjects who were negative for the vaccine HPV types, high seroconversion rates and high levels of anti-HPV antibodies were observed in females of all age ranges from 9 to 45 years and in males aged 9-26 years. The vaccine was generally well tolerated and was usually predicted to be cost effective in girls and young women. Therefore, quadrivalent HPV vaccine offers an effective means to substantially reduce the burden of HPV-related anogenital disease in females and males, particularly cervical cancer and genital warts.

Trends in head and neck cancers in England from 1995 to 2011 and projections up to 2025

BACKGROUND

The magnitude of the growing burden of oropharyngeal cancers (OPC), a sub-set of head and neck cancers (HNC), is unknown in England.

METHODS

Data were extracted from population-based cancer registries in England. The burden of HNC overall and by anatomic site was described from 1995 to 2011. Projections of future rates up to 2025 were estimated using flexible age-period-cohort modelling.

RESULTS

HNC increased by 59% between 1995 and 2011 in England. Projections indicate that the number of HNC cases will increase by 55% from 2011, totalling 11,748 new cases in 2025, ranking HNC as the sixth most common cancer. Of the anatomic sites, OPC is projected to account for 35% of HNC with the largest rate increase (annual percentage change, +7.3% for men and +6.2% for women between 2011 and 2025), predominantly affecting males <60years. This projected burden is equivalent to a 239% increase in number of OPC cases. Incidence of the oral cavity, salivary glands and palate are projected to rise at lower rates, whereas rates of the nasopharynx, hypopharynx and larynx remain relatively stable or decreasing.

CONCLUSION

The substantial recent and predicted future significant increase in OPC highlights the need for prioritising the provision of cancer services for the considerable burden of OPC patients and survivors and cancer control strategies.

Comparison of two dose and three dose human papillomavirus vaccine schedules: cost effectiveness analysis based on transmission model

OBJECTIVE

To investigate the incremental cost effectiveness of two dose human papillomavirus vaccination and of additionally giving a third dose.

DESIGN

Cost effectiveness study based on a transmission dynamic model of human papillomavirus vaccination. Two dose schedules for bivalent or quadrivalent human papillomavirus vaccines were assumed to provide 10, 20, or 30 years' vaccine type protection and cross protection or lifelong vaccine type protection without cross protection. Three dose schedules were assumed to give lifelong vaccine type and cross protection.

SETTING

United Kingdom.

POPULATION

Males and females aged 12-74 years.

INTERVENTIONS

No, two, or three doses of human papillomavirus vaccine given routinely to 12 year old girls, with an initial catch-up campaign to 18 years.

MAIN OUTCOME MEASURE

Costs (from the healthcare provider's perspective), health related utilities, and incremental cost effectiveness ratios.

RESULTS

Giving at least two doses of vaccine seems to be highly cost effective across the entire range of scenarios considered at the quadrivalent vaccine list price of £86.50 (€109.23; $136.00) per dose. If two doses give only 10 years' protection but adding a third dose extends this to lifetime protection, then the third dose also seems to be cost effective at £86.50 per dose (median incremental cost effectiveness ratio £17,000, interquartile range £11,700-£25,800). If two doses protect for more than 20 years, then the third dose will have to be priced substantially lower (median threshold price £31, interquartile range £28-£35) to be cost effective. Results are similar for a bivalent vaccine priced at £80.50 per dose and when the same scenarios are explored by parameterising a Canadian model (HPV-ADVISE) with economic data from the United Kingdom.

CONCLUSIONS

Two dose human papillomavirus vaccine schedules are likely to be the most cost effective option provided protection lasts for at least 20 years. As the precise duration of two dose schedules may not be known for decades, cohorts given two doses should be closely monitored.

Human papillomavirus vaccines: key factors in planning cost-effective vaccination programs

Prophylactic HPV vaccines hold tremendous potential for reducing cervical and non-cervical HPV-related disease burden worldwide. To maximize on this potential, policy officials will need to carefully consider available evidence, existing uncertainties and the cost-effectiveness of mass HPV vaccination programs in the context of their respective nations and/or regions. Proper harmonization of primary prevention strategies with secondary prevention efforts will also be important. Decisions following such considerations may ultimately depend on programmatic objectives, infrastructure and available resources. Continued research and surveillance surrounding HPV vaccination will be essential for filling current knowledge gaps, and forcing ongoing reconsiderations of selected immunization strategies.

Two-dose strategies for human papillomavirus vaccination: how well do they need to protect?

BACKGROUND

Two-dose human papillomavirus (HPV) vaccine schedules may provide short-term protection but their long-term population impact is unknown.

METHODS

Two models of HPV transmission and associated cervical disease (squamous and glandular, neoplasia and cancer) were fitted to data from England and Canada on HPV epidemiology, sexual behaviour, cervical screening outcomes and cervical cancer incidence.

RESULTS

Models suggest that at 40-80% coverage, if two-dose schedules protect vaccinees for 20 years, then the benefits of the third dose are small. If two doses protect for 10 years, then the third dose may prevent as many cancers as the first two. At 80% coverage, numbers needed to receive a third dose to prevent an additional cancer are 5900-110,000 (England), 3000-5100 (Canada) with 20 years two-dose protection, and 2000-5300 (England), 760-950 (Canada) with 10 years two-dose protection.

CONCLUSION

Results enable decision makers to quantify risks associated with two-dose schedules despite remaining uncertainties in vaccine duration and cross-protection.