Evolution of the health economics of cervical cancer vaccination

[Comparative study of factors influencing cytological screening for cervical cancer attendance in Hungary among Roma and non-Roma population, in relation to Slovak and Romanian results]

INTRODUCTION

To the present day, the prevalence and incidence of cervical cancer remains very significant. For disadvantaged groups such as the Roma, screening for the disease should be given increased attention, as members of this minority have lower access to health care and lower average health literacy.

OBJECTIVE

The aim of our study was to assess the prevalence of cytological screening for cervical cancer among Hungarian-speaking Roma and non-Roma populations in Hungary, Romania and Slovakia, in relation to the possible influencing factors. We also investigated respondents' perceptions of the importance of cervical cancer screening and HPV vaccination. In this paper, we focus on presenting the data from Hungary in relation to the results from the other two countries. The study sample size was 1366.

METHOD

Data were presented as mean ± SD and proportion. To compare Roma and non-Roma samples, the independent samples t-test was used. Cross tabulation with Pearson's chi-square test with calculating phi/Cramér's V effect size (p<0.05) was used to reveal association between ethnicity and studied variables.

RESULTS

In Hungary, a higher proportion of Roma women (p = 0.004) did not attend cytological screening for cervical cancer compared to non-Roma women, a difference confirmed in the other two countries. Non-Roma women attached greater importance to attendance at cervical cancer screening (p = 0.022). The Roma population aged 18-65 years had lower rates of annual cytological screening for cervical cancer compared to non-Roma in all age groups, while the annual screening rate decreased with age, regardless of ethnicity.

CONCLUSION

Further health promotion to prevent cervical cancer in the Roma and non-Roma population would be necessary, regardless of national borders, specifically to address risk factors in all age groups, with a focus on young people, who are less aware of the risk, and older age groups, who mostly believe that the disease does not affect them due to their age. Orv Hetil. 2023; 164(36): 1416-1425.

Transmission reduction and prevention with HPV vaccination (TRAP-HPV) study protocol: a randomised controlled trial of the efficacy of HPV vaccination in preventing transmission of HPV infection in heterosexual couples

INTRODUCTION

Human papillomavirus (HPV) is a causal agent of malignancies including cervical, vulvar, vaginal, penile, anal and oropharyngeal cancer, as well as benign conditions such as anogenital warts. HPV vaccination protects individuals against infections with the target HPV types and their clinical outcomes. However, little is known about the protection an immunised individual confers to their sexual partner or its impact on HPV transmission dynamics. In this context, the Transmission Reduction and Prevention with HPV vaccination (TRAP-HPV) study was designed to determine the efficacy of an HPV vaccine in reducing transmission of genital and oral HPV infection in sexual partners of vaccinated individuals.

METHODS AND ANALYSIS

The TRAP-HPV study is an ongoing randomised controlled trial among heterosexual couples living in Montreal, Canada. Sexually active couples, aged between 18 and 45 years, who have been in a relationship no longer than 6 months are considered eligible. Participants are independently randomised to receive either the intervention HPV vaccine, Gardasil 9, or a placebo hepatitis A vaccine, Avaxim, creating four vaccination groups among couples: intervention-intervention, intervention-placebo, placebo-intervention and the placebo-placebo. Participants provide genital (vaginal/penile) and oral samples at baseline and five follow-up visits over a 1-year duration. Linear Array HPV genotyping is used to detect 36 HPV types. Cox proportional hazard regression models will be used to estimate the effect of vaccination on HPV transmission.

ETHICS AND DISSEMINATION

The TRAP-HPV study received ethical approval by institutional review boards McGill University, Concordia University and Centre Hospitalier de l'Université de Montréal. Before enrolment, all participants provide informed written consent. Results will be published in peer-reviewed journals and presented at national and international conferences. The generated empirical evidence could be used in mathematical models of vaccination to inform policymakers in Canada and elsewhere.

TRIAL REGISTRATION NUMBER

NCT01824537.

How to assess for the full economic value of vaccines? From past to present, drawing lessons for the future

Background:Cost-effectiveness analysis (CEA) is the economic analysis method most commonly applied today in the context of replacing one treatment with a new one in a developed healthcare system to improve efficiency. CEA is often requested by local healthcare decision-makers to grant reimbursement. New preventative interventions, such as new vaccines, may however have much wider benefits inside and outside healthcare, when compared with treatment. These additional benefits include externalities on indirect clinical impact, reallocation of specific healthcare resources, improved quality of care, better productivity, better disease control, better fiscal revenues, and others. But these effects are sometimes difficult to integrate into a meaningful CEA result. They may appear as specific benefits for specific stakeholders, other than the stakeholders in healthcare. Objective: Based on a historical view about the application of economic assessments for vaccines our objective has been to make the inventory of who was/is interested in knowing the economic value of vaccines, in what those different stakeholders are likely to see the benefit from their perspective and how  were/are we able to measure those benefits and to report them well. Results: The historical view disclosed a limited interest in the economic assessment of vaccines at start, more than 50 years ago, that was comparable to the assessment of looking for more efficiency in new industries through optimization exercises. Today, we are exposed to a very rich panoply of different stakeholders (n= 16). They have their specific interest in many different facets of the vaccine benefit of which some are well known in the conventional economic analysis (n=9), but most outcomes are hidden and not enough evaluated and reported (n=26). Meanwhile we discovered that many different methods of evaluation have been explored to facilitate the measurement and reporting of the benefits (n=18). Conclusion: Our recommendation for future economic evaluations of new vaccines is therefore to find the right combination among the three entities of stakeholder type selection, outcome measure of interest for each stakeholder, and the right method to apply. We present at the end examples that illustrate how successful this approach can be.

Simple but not simpler: a systematic review of Markov models for economic evaluation of cervical cancer screening

The aim of this study was to critically evaluate the quality of the models used in economic evaluations of screening strategies for cervical cancer prevention. We systematically searched multiple databases, selecting model-based full economic evaluations (cost-effectiveness analyses, cost-utility analyses, and cost-benefit analyses) of cervical cancer screening strategies. Two independent reviewers screened articles for relevance and performed data extraction. Methodological assessment of the quality of the models utilized formal checklists, and a qualitative narrative synthesis was performed. Thirty-eight articles were reviewed. The majority of the studies were conducted in high-income countries (82%, n=31). The Pap test was the most used screening strategy investigated, which was present in 86% (n=33) of the studies. Half of the studies (n=19) used a previously published Markov model. The deterministic sensitivity analysis was performed in 92% (n=35) of the studies. The mean number of properly reported checklist items was 9 out of the maximum possible 18. Items that were better reported included the statement of decision problem, the description of the strategies/comparators, the statement of time horizon, and information regarding the disease states. Compliance with some items of the checklist was poor. The Markov models for economic evaluation of screening strategies for cervical cancer varied in quality. The following points require improvement: 1) assessment of methodological, structural, heterogeneity, and parameter uncertainties; 2) model type and cycle length justification; 3) methods to account for heterogeneity; and 4) report of consistency evaluation (through calibration and validation methods).

Cost-effectiveness of two-dose human papillomavirus vaccination in Singapore

INTRODUCTION

Cervical cancer is the tenth most common cancer and the eighth most frequent cause of death among women in Singapore. As human papillomavirus (HPV) infection is the necessary cause of cervical cancer, the risk of cervical cancer can be substantially reduced through vaccination. This study was conducted to evaluate the cost-effectiveness of two-dose HPV vaccination as part of a national vaccination programme for 12-year-old girls in Singapore, from the perspective of the healthcare payer.

METHODS

A lifetime Markov cohort model was used to evaluate the cost-effectiveness of introducing the AS04-adjuvanted HPV-16/18 vaccine (AS04-HPV-16/18v) to the current cervical screening programme in Singapore. Furthermore, the cost-effectiveness of the AS04-HPV-16/18v was compared with the HPV-6/11/16/18 vaccine (4vHPV). Model inputs were derived from local data, where possible, and validated by clinical experts in Singapore.

RESULTS

Introduction of the AS04-HPV-16/18v in Singapore was shown to prevent 137 cervical cancer cases and 48 cervical cancer deaths when compared with screening alone. This resulted in an incremental cost-effectiveness ratio of SGD 12,645 per quality-adjusted life year (QALY) gained, which is cost-effective according to the World Health Organization threshold for Singapore. When discounted at 3%, AS04-HPV-16/18v was dominant over 4vHPV, with cost savings of SGD 80,559 and 28 additional QALYs gained. In the one-way sensitivity analysis, AS04-HPV-16/18v remained cost-effective compared with screening alone and dominant compared with 4vHPV.

CONCLUSION

AS04-HPV-16/18v is the most cost-effective choice for reducing the burden of cervical cancer through universal mass vaccination for 12-year-old girls in Singapore.

Challenges in Cost-Effectiveness Analysis Modelling of HPV Vaccines in Low- and Middle-Income Countries: A Systematic Review and Practice Recommendations

BACKGROUND

Low- and middle-income countries (LMICs) face a number of challenges in implementing cervical cancer prevention programmes that do not apply in high-income countries.

OBJECTIVE

This review assessed how context-specific challenges of implementing cervical cancer prevention strategies in LMICs were accounted for in existing cost-effectiveness analysis (CEA) models of human papillomavirus (HPV) vaccination.

METHODS

The databases of MEDLINE, EMBASE, NHS Economic Evaluation Database, EconLit, Web of Science, and the Center for the Evaluation of Value and Risk in Health (CEA) Registry were searched for studies published from 2006 to 2015. A descriptive, narrative, and interpretative synthesis of data was undertaken.

RESULTS

Of the 33 studies included in the review, the majority acknowledged cost per vaccinated girl (CVG) (26 studies) and vaccine coverage rate (21 studies) as particular challenges for LMICs, while nine studies identified screening coverage rate as a challenge. Most of the studies estimated CVG as a composite of different cost items. However, the basis for the items within this composite cost was unclear. The majority used an assumption rather than an observed rate to represent screening and vaccination coverage rates. CVG, vaccine coverage and screening coverage were shown by some studies through sensitivity analyses to reverse the conclusions regarding cost-effectiveness, thereby significantly affecting policy recommendations.

CONCLUSIONS

While many studies recognized aspects of the particular challenges of HPV vaccination in LMICs, greater efforts need to be made in adapting models to account for these challenges. These include adapting costings of HPV vaccine delivery from other countries, learning from the outcomes of cervical cancer screening programmes in the same geographical region, and taking into account the country's previous experience with other vaccination programmes.

Development of a quality framework for models of cervical screening and its application to evaluations of the cost-effectiveness of HPV vaccination in developed countries

BACKGROUND

HPV vaccination has now been introduced in most developed countries, but this has occurred in the context of established cervical cancer screening mechanisms which provide population-level protection against the most common HPV-related cancer. Therefore, estimating the cost-effectiveness of HPV vaccination to further reduce HPV-related disease depends in large part on the estimation of the effectiveness of the cervical screening 'background'. The aim of this study was to systematically review and assess methods for simulating cervical screening in decision analytic models used for evaluation of HPV vaccination.

METHODS

Existing quality frameworks for economic models were extended to develop a specific quality framework for models of cervical screening. This involved domains for model structure, parameterisation (data sources) and validation (consistency). A systematic review of economic evaluations of HPV vaccination was then conducted, and assessment of cervical screening model components was then performed via application of the new quality framework.

RESULTS

Generally, models took into account population-level cervical screening participation, but were inconsistent in their approach to modelling abnormal smear management, diagnostic evaluation and treatment of precancerous disease. There was also considerable variability in the accuracy of modelling clinical pathways and the scope of validation performed for screening-related outcomes, with focus directed towards cervical cancer targets. Only a few models comprehensively validated against observed pre-cancerous abnormalities.

CONCLUSION

Models of HPV vaccination in developed countries can be improved by further attention to the 'background' modelling of secondary protection via cervical screening. The quality framework developed for this review can be used to inform future HPV vaccination evaluations, including evaluations of the cost-effectiveness of male vaccination and next generation HPV vaccines, and to assess models used to evaluate new cervical screening technologies and recommendations.

Cost-effectiveness of human papillomavirus vaccination in low and middle income countries: a systematic review

The World Health Organization recommends establishing that human papillomavirus vaccination is cost-effective before vaccine introduction. We searched Pubmed, Embase and the Cochrane Library to 1 April 2012 for economic evaluations of human papillomavirus vaccination in low and middle income countries. We found 25 articles, but almost all low income countries and many middle income countries lacked country-specific studies. Methods, assumptions and consequently results varied widely, even for studies conducted for the same country. Despite the heterogeneity, most studies conclude that vaccination is likely to be cost-effective and possibly even cost saving, particularly in settings without organized cervical screening programmes. However, study uncertainty could be reduced by clarity about vaccine prices and vaccine delivery costs. The review supports extending vaccination to low income settings where vaccine prices are competitive, donor funding is available, cervical cancer burden is high and screening options are limited.

Categorization of methods used in cost-effectiveness analyses of vaccination programs based on outcomes from dynamic transmission models

The aim of this study is to categorize methods used to estimate the cost-effectiveness of vaccination programs using dynamic transmission models, and assess value to decision-makers. A targeted literature search of PubMed has been carried out for this purpose. A review of 43 articles presenting cost-effectiveness analyses of vaccination programs based on dynamic transmission models identified four methods for the estimation of a cost-effectiveness ratio: cumulative population values over a fixed time horizon; population values for a steady-state year; cohort values from time of program initiation; and cohort values at steady state. Cost-effectiveness estimates are sensitive to the choice of time horizon or number of cohorts included. Estimates at steady state are the most comparable to estimates for other healthcare interventions but do not account for pre-steady-state periods. Population values provide estimates of budget impact. In conclusion, four different methods were identified for converting clinical outcomes from a dynamic transmission model to cost-effectiveness estimates. Sensitivity analyses for time horizon or number of cohorts considered should be routinely performed.

Human papillomavirus vaccine introduction in low-income and middle-income countries: guidance on the use of cost-effectiveness models

BACKGROUND

The World Health Organization (WHO) recommends that the cost effectiveness of introducing human papillomavirus (HPV) vaccination is considered before such a strategy is implemented. However, developing countries often lack the technical capacity to perform and interpret results of economic appraisals of vaccines. To provide information about the feasibility of using such models in a developing country setting, we evaluated models of HPV vaccination in terms of their capacity, requirements, limitations and comparability.

METHODS

A literature review identified six HPV vaccination models suitable for low-income and middle-income country use and representative of the literature in terms of provenance and model structure. Each model was adapted by its developers using standardised data sets representative of two hypothetical developing countries (a low-income country with no screening and a middle-income country with limited screening). Model predictions before and after vaccination of adolescent girls were compared in terms of HPV prevalence and cervical cancer incidence, as was the incremental cost-effectiveness ratio of vaccination under different scenarios.

RESULTS

None of the models perfectly reproduced the standardised data set provided to the model developers. However, they agreed that large decreases in type 16/18 HPV prevalence and cervical cancer incidence are likely to occur following vaccination. Apart from the Thai model (in which vaccine and non-vaccine HPV types were combined), vaccine-type HPV prevalence dropped by 75% to 100%, and vaccine-type cervical cancer incidence dropped by 80% to 100% across the models (averaging over age groups). The most influential factors affecting cost effectiveness were the discount rate, duration of vaccine protection, vaccine price and HPV prevalence. Demographic change, access to treatment and data resolution were found to be key issues to consider for models in developing countries.

CONCLUSIONS

The results indicated the usefulness of considering results from several models and sets of modelling assumptions in decision making. Modelling groups were prepared to share their models and expertise to work with stakeholders in developing countries. Please see related article: http://www.biomedcentral.com/1741-7007/9/55.

Modelling the economic value of cross- and sustained-protection in vaccines against cervical cancer

OBJECTIVE

Two human papillomavirus (HPV) vaccines are on the market. Based on expected differences in sustained- and cross-protection between the two vaccines, their long-term economic value is modelled and compared for France, Ireland and Italy.

METHODS

A Markov cohort model reproducing the natural history of HPV infections, screening and vaccination, is adapted to country-specific data. Two hypothetical HPV vaccines (VA and VB) are compared. At baseline VA provides lifetime protection against HPV-16 and 10-year protection against HPV-18 before waning. VB is the same as VA with a 10-year protection against HPV-6 and 11. Sustained- and cross-protection is varied over wide ranges in VA to define the levels that could make VA cost-effective or dominant compared with VB.

RESULTS

Under baseline conditions VB dominates VA. VA becomes cost-effective when the difference in cross-protection alone reaches 13-15% (undiscounted), and 22-44% (discounted). A combination of sustained- and cross-protection is required for VA to dominate VB (discounted). The results are dependent upon country, the base-case value and the discount applied.

CONCLUSION

Realistic additional sustained- and cross-protection in one HPV vaccine may confer benefits that offset the economic value of protection against low-risk HPV in the other. The results are country specific.

Economic evaluations of massive HPV vaccination: within-study and between study variations in incremental cost per QALY gained

OBJECTIVE

We describe the heterogeneity of the estimates of the incremental cost per quality-adjusted year of life (QALY) within and between cost-utility studies of the human papillomavirus (HPV) vaccine.

METHOD

We searched for articles in English published in peer-reviewed journals that perform cost-utility analyses to evaluate the addition of HPV vaccine to 12-year-old girls to existing cervical cancer screening practices. Fifteen studies were selected according to our inclusion and exclusion criteria.

RESULTS

There are large within-study variations in estimates of the cost per QALY gained. The most influential source of uncertainty is the duration of the vaccine protection. Between-study variations are mainly due to three causes: methodological differences, assumptions, and local conditions in the application area. We find large variations between studies for a given country.

DISCUSSION

Economic evaluation models are increasingly sophisticated, but scientific treatment of epidemiological and market uncertainty does not compensate for the lack of basic information.

CONCLUSIONS

The large disparities in cost per QALY estimates of massive vaccination programs around the world may be attributed to several critical sources (unavoidable and avoidable) of uncertainty. An asset of economic evaluation is the ability to highlight the areas of research that could be undertaken to reduce uncertainty.

Human papillomavirus vaccine: a paradigm shift for pediatricians

PURPOSE OF REVIEW

Recommendations for human papillomavirus (HPV) vaccination during adolescence primarily for a disease, cancer, that occurs only during adulthood is a paradigm shift for pediatricians. Additional postlicensure data and guidelines about HPV biology and epidemiology, disease association, adverse effects, vaccination during pregnancy, and cost-benefit analyses are now available to inform pediatricians and guide HPV vaccination recommendations.

RECENT FINDINGS

The prespecified, end-of-study combined analysis of HPV vaccine efficacy studies for prevention of cervical cancer, and now also for prevention of vulvar and vaginal cancers, confirmed 98-100% vaccine efficacy. Postlicensure surveillance identified a new association of vaccine administration with syncope, and provides assurance of the safety of inadvertent vaccination during pregnancy. Several cost-effectiveness analyses consistently demonstrated that HPV vaccination of 12-year-old girls and catch-up vaccination through 18 years of age, and possibly to 26 years of age, is cost-effective, although the thresholds of affordability vary by study. The downward trend in age of initial HPV infection and the need to educate parents and patients about HPV disease and vaccination underscore the essential role of pediatricians in managing HPV illness.

SUMMARY

It is critical for pediatricians to thoroughly understand HPV biology and disease and champion HPV vaccination to prevent cervical, vulvar, and vaginal cancers, even though these benefits accrue during adulthood and will likely require 2-4 decades to realize the financial and public health benefits. Several new developments are expected in the near future, including licensure for use in boys and men and the approval of a second, bivalent HPV vaccine.