Cost Effectiveness of HPV Vaccination: A Systematic Review of Modelling Approaches

Model parameters influencing the cost-effectiveness of sacubitril/valsartan in heart failure: evidence from a systematic literature review

OBJECTIVES

To summarize cost-effectiveness (CE) evidence of sacubitril/valsartan for the treatment of heart failure (HF) patients with reduced ejection fraction (HFrEF). The impact of different modeling approaches and parameters on the CE results is also described.

METHODS

We conducted a systematic literature review using multiple databases: Embase^®; MEDLINE^®; MEDLINE^®-In Process; NIHR CRD database including DARE, NHS EED, and HTA databases; and the Cost Effectiveness Analysis registry. We also reviewed HTA countries' websites to identify CE reports of sacubitril/valsartan, published up to 25-July-2021. Articles published in English as full-texts, conference-abstracts, or HTA reports were included.

RESULTS

We included 44 CE models [39 from 37 publications (22 full-texts; 15 conference-abstracts) and 5 HTAs; Europe, n = 20; North and South Americas, n = 14; Asia and Australia, n = 10]. Most models adopted a Markov structure with constant transition probabilities of events (n = 27) or a mix of Markov and regression-based models (n = 16), with variations in structural assumptions and chosen parameters. Study authors concluded sacubitril/valsartan to be a cost-effective therapy in 37/41 models in chronic HFrEF patients and 2/3 models in hospitalized patients stabilized after an acute decompensation for HF. CE models showing sacubitril/valsartan not to be a cost-effective treatment generally modeled a shorter time horizon. Effect of sacubitril/valsartan on cardiovascular and all-cause mortality, cost, duration of effect and time horizon was the main model drivers.

CONCLUSIONS

Most evidence indicated sacubitril/valsartan is cost-effective in HFrEF. The use of a lifetime horizon is recommended in future models as HF is a chronic disease. Data on the CE of sacubitril/valsartan in the inpatient setting were limited and further research is warranted.

An Umbrella Review of the Cost Effectiveness of Human Papillomavirus Vaccines

BACKGROUND AND OBJECTIVES

Although many systematic reviews for the human papillomavirus vaccines cost effectiveness have been published, they vary in perspectives, methods, and quality. We aimed to condense systematically such evidence to facilitate locating, processing, and learning, not only about the consensus of findings but also how models were built and their evolution over time and across settings.

METHODS

We conducted an umbrella review of cost-effectiveness studies for human papillomavirus vaccines using three databases (PubMed, Embase, and Cochrane). Based on their objectives, we classified studies into three groups (human papillomavirus vaccines cost effectiveness, model characteristics, and all-type vaccines, including human papillomavirus vaccines). We used the AMTAR2 to assess the quality of the studies. Additionally, we provided a summary of study findings, discussions, and evidence gaps in the literature.

RESULTS

Though most studies were critically low quality and had a low quality of reporting, the human papillomavirus vaccine was consistently cost effective in young girls and men who have sex with men. Stratified analyses by rated quality did not change the results. The quality assessment of the reviews did not necessarily reflect the quality assessment of underlying studies. The human papillomavirus vaccine models became more complex over time, capturing more realistic disease transmission with different human papillomavirus strains and herd immunities.

CONCLUSIONS

Additional evidence is needed for vulnerable populations (e.g., childhood cancer survivors) who are at high risk for human papillomavirus vaccine-related cancers and, therefore, may be more cost effective when receiving human papillomavirus vaccines. Quantifying human papillomavirus vaccine cost effectiveness via meta-analyses is feasible if investigators can increase the homogeneity of their populations.

Cost-effectiveness of human papillomavirus vaccine in China: a systematic review of modelling studies

OBJECTIVES

China suffers from high burdens of human papillomavirus (HPV) and cervical cancer, whereas the uptake of HPV vaccine remains low. The first Chinese domestic HPV vaccine was released in 2019. However, collective evidence on cost-effectiveness of HPV vaccination in China has yet to be established. We summarised evidence on the cost-effectiveness of HPV vaccine in China.

DESIGN

Systematic review and narrative synthesis DATA SOURCES: PubMed, EMBASE, China National Knowledge Infrastructure and Wanfang Data were searched through 2 January 2021 ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Cost-effectiveness studies using a modelling approach focusing on HPV vaccination interventions in the setting of China were included for review.

DATA EXTRACTION AND SYNTHESIS

We extracted information from the selected studies focusing on cost-effectiveness results of various vaccination programmes, key contextual and methodological factors influencing cost-effectiveness estimates and an assessment of study quality.

RESULTS

A total of 14 studies were included for review. Considerable heterogeneity was found in terms of the methodologies used, HPV vaccination strategies evaluated and study quality. The reviewed studies generally supported the cost-effectiveness of HPV vaccine in China, although some reached alternative conclusions, particularly when assessed incremental to cervical cancer screening. Cost of vaccination was consistently identified as a key determinant for the cost-effectiveness of HPV vaccination programmes.

CONCLUSIONS

Implementing HPV vaccination programmes should be complemented with expanded cervical cancer screening, while the release of lower-priced domestic vaccine offers more promising potential for initiating public HPV vaccination programmes. Findings of this study contributes important evidence for policies for cervical cancer prevention in China and methodological implications for future modelling efforts.

Human papillomavirus (HPV) vaccination: from clinical studies to immunization programs

Cervical cancer incidence and mortality have decreased in high-income countries, but low- and middle-income countries continue to bear a significant burden from the disease. Human papillomavirus (HPV) vaccines are a promising alternative for disease control; however, their introduction is slow in settings with greater need. We conducted a review of HPV vaccine efficacy and effectiveness reported in clinical trials and population-based studies. Efficacy of HPV vaccines is close to 100% when using a three-dose schedule in HPV-negative young women (<25 years old) for protection against persistent infection and HPV vaccine-type associated pre-cancerous lesions. Furthermore, sustained protection for up to 12 years of follow-up has been demonstrated; cross-protection against non-vaccine types is particularly observed for the bivalent vaccine, and preliminary data regarding impact on invasive cancer have emerged. Given its lower efficacy, catch-up vaccination beyond 19 years of age and proposals for vaccinating adult women deserve careful evaluation in accurately designed studies and economic analyses. Despite positive results regarding immunogenicity and post-hoc analysis for cervical intra-epithelial neoplasia in clinical trials, population-based data for prime and booster two-dose schedules are not available. Evaluation of vaccine safety from surveillance systems in immunization programs that have already distributed more than 270 million doses found no association of HPV vaccination with serious side effects. The introduction of HPV vaccination in national immunization programs remains the main challenge in tackling the burden of cervical cancer (up to 2018, only 89 countries have introduced vaccination worldwide, and most of these are high-income countries). Access models and technical capacity require further development to help low- and middle-income countries to increase the pace of vaccine delivery. Alternative approaches such as one-dose schedules and vaccination at younger ages may help reduce the programmatic and economic challenges to adolescent vaccination.

Cost-effectiveness of adult vaccinations: A systematic review

BACKGROUND

Coverage levels for many recommended adult vaccinations are low. The cost-effectiveness research literature on adult vaccinations has not been synthesized in recent years, which may contribute to low awareness of the value of adult vaccinations and to their under-utilization. We assessed research literature since 1980 to summarize economic evidence for adult vaccinations included on the adult immunization schedule.

METHODS

We searched PubMed, EMBASE, EconLit, and Cochrane Library from 1980 to 2016 and identified economic evaluation or cost-effectiveness analysis for vaccinations targeting persons aged ≥18 years in the U.S. or Canada. After excluding records based on title and abstract reviews, the remaining publications had a full-text review from two independent reviewers, who extracted economic values that compared vaccination to "no vaccination" scenarios.

RESULTS

The systematic searches yielded 1688 publications. After removing duplicates, off-topic publications, and publications without a "no vaccination" comparison, 78 publications were included in the final analysis (influenza = 25, pneumococcal = 18, human papillomavirus = 9, herpes zoster = 7, tetanus-diphtheria-pertussis = 9, hepatitis B = 9, and multiple vaccines = 1). Among outcomes assessing age-based vaccinations, the percent indicating cost-savings was 56% for influenza, 31% for pneumococcal, and 23% for tetanus-diphtheria-pertussis vaccinations. Among age-based vaccination outcomes reporting $/QALY, the percent of outcomes indicating a cost per QALY of ≤$100,000 was 100% for influenza, 100% for pneumococcal, 69% for human papillomavirus, 71% for herpes zoster, and 50% for tetanus-diphtheria-pertussis vaccinations.

CONCLUSIONS

The majority of published studies report favorable cost-effectiveness profiles for adult vaccinations, which supports efforts to improve the implementation of adult vaccination recommendations.

Advances in Designing and Developing Vaccines, Drugs and Therapeutic Approaches to Counter Human Papilloma Virus

Human papillomavirus (HPV) is a viral infection with skin-to-skin based transmission mode. HPV annually caused over 500,000 cancer cases including cervical, anogenital and oropharyngeal cancer among others. HPV vaccination has become a public-health concern, worldwide, to prevent the cases of HPV infections including precancerous lesions, cervical cancers, and genital warts especially in adolescent female and male population by launching national programs with international alliances. Currently, available prophylactic and therapeutic vaccines are expensive to be used in developing countries for vaccination programs. The recent progress in immunotherapy, biotechnology, recombinant DNA technology and molecular biology along with alternative and complementary medicinal systems have paved novel ways and valuable opportunities to design and develop effective prophylactic and therapeutic vaccines, drugs and treatment approach to counter HPV effectively. Exploration and more researches on such advances could result in the gradual reduction in the incidences of HPV cases across the world. The present review presents a current global scenario and futuristic prospects of the advanced prophylactic and therapeutic approaches against HPV along with recent patents coverage of the progress and advances in drugs, vaccines and therapeutic regimens to effectively combat HPV infections and its cancerous conditions.

Medical Care Costs Associated with Genital Warts for Commercially Insured US Patients

INTRODUCTION

Genital warts are caused by infection with human papillomavirus (HPV) and are associated with significant morbidity. Primary prevention of genital warts is possible through HPV vaccination, but vaccination rates remain low in the USA. When deciding to implement HPV vaccination programs, public health officials and policy makers rely on cost-effectiveness studies that accurately reflect costs associated with morbidity and mortality. However, previous information on the cost of treating genital warts was outdated.

OBJECTIVES

We estimated the mean direct medical care costs associated with genital warts in the USA.

METHODS

This was a retrospective case-control study of patients diagnosed with genital warts and matched controls. We used commercial healthcare claims data from 2011 through 2014 to estimate total 1- and 2-year costs from date of diagnosis. We used a generalized linear model to identify factors associated with monthly costs.

RESULTS

We identified 34,686 eligible cases of genital warts during the period 2011-2014. The first 2-year mean direct medical cost differences between cases and controls were US$6737 for the USA. Costs were significantly higher in the first 3 months following diagnosis and were higher among older individuals, women, those with co-morbidities or psychiatric illnesses, and those located in the south and southwest USA.

CONCLUSIONS

The mean direct cost of treating genital warts is approximately US$6700 in the first 2 years after diagnosis in the USA. These data can assist policy makers in decisions with respect to allocation of resources to implement HPV vaccine programs.

Simultaneously characterizing the comparative economics of routine female adolescent nonavalent human papillomavirus (HPV) vaccination and assortativity of sexual mixing in Hong Kong Chinese: a modeling analysis

BACKGROUND

Although routine vaccination of females before sexual debut against human papillomavirus (HPV) has been found to be cost-effective around the world, its cost-benefit has rarely been examined. We evaluate both the cost-effectiveness and cost-benefit of routine female adolescent nonavalent HPV vaccination in Hong Kong to guide its policy, and by extension that of mainland China, on HPV vaccination. One major obstacle is the lack of data on assortativity of sexual mixing. Such difficulty could be overcome by inferring sexual mixing parameters from HPV epidemiologic data.

METHODS

We use an age-structured transmission model coupled with stochastic individual-based simulations to estimate the health and economic impact of routine nonavalent HPV vaccination for girls at age 12 on cervical cancer burden and consider vaccine uptake at 25%, 50%, and 75% with at least 20 years of vaccine protection. Bayesian inference was employed to parameterize the model using local data on HPV prevalence and cervical cancer incidence. We use the human capital approach in the cost-benefit analysis (CBA) and GDP per capita as the indicative willingness-to-pay threshold in the cost-effectiveness analysis (CEA). Finally, we estimate the threshold vaccine cost (TVC), which is the maximum cost for fully vaccinating one girl at which routine female adolescent nonavalent HPV vaccination is cost-beneficial or cost-effective.

RESULTS

As vaccine uptake increased, TVC decreased (i.e., economically more stringent) in the CBA but increased in the CEA. When vaccine uptake was 75% and the vaccine provided only 20 years of protection, the TVC was US$444 ($373-506) and $689 ($646-734) in the CBA and CEA, respectively, increasing by approximately 2-4% if vaccine protection was assumed lifelong. TVC is likely to be far higher when non-cervical diseases are included. The inferred sexual mixing parameters suggest that sexual mixing in Hong Kong is highly assortative by both age and sexual activity level.

CONCLUSIONS

Routine HPV vaccination of 12-year-old females is highly likely to be cost-beneficial and cost-effective in Hong Kong. Inference of sexual mixing parameters from epidemiologic data of prevalent sexually transmitted diseases (i.e., HPV, chlamydia, etc.) is a potentially fruitful but largely untapped methodology for understanding sexual behaviors in the population.

Cost Effectiveness of Human Papillomavirus Vaccination for Men Who have Sex with Men; Reviewing the Available Evidence

BACKGROUND

Men who have sex with men require special attention for human papillomavirus vaccination given elevated infection risks and the development of, in particular, anal cancer.

OBJECTIVE

Our purpose was to review the cost effectiveness of human papillomavirus vaccination for both currently vaccine-eligible and non-eligible individuals, particularly the men-who-have-sex-with-men population, and synthesize the available evidence.

METHODS

We systematically searched for published articles in two main databases (PubMed and EMBASE). Screening and data extraction were performed by two independent reviewers. The risk of bias was assessed using a validated instrument (Bias in Economic Evaluation, ECOBIAS). Methodological aspects, study results, and sensitivity analyses were extracted and synthesized to generate a consistent overview of the cost effectiveness of human papillomavirus vaccination in the men-who-have-sex-with-men population.

RESULTS

From 770 identified articles, four met the inclusion criteria. Across the studies, human papillomavirus vaccination showed incremental cost-effectiveness ratios ranging from dominant to US$96,146 and US$14,000 to US$18,200 for tertiary prevention and primary prevention, respectively. The incremental cost-effectiveness ratio seemed most sensitive to vaccine efficacy, vaccine costs, and the incidence of anal cancer in the selected target populations.

CONCLUSION

This review presents the human papillomavirus vaccine, both as a primary and adjuvant (tertiary) vaccination, as a potentially cost-effective strategy for preventing mainly-but not limited to only-anal cancer in men-who-have-sex-with-men populations.

Human papillomavirus vaccination and the role of herd effects in future cancer control planning: a review

INTRODUCTION

Vaccine herd effects are the indirect protection that vaccinated persons provide to those who remain susceptible to infection, due to the reduced transmission of infections. Herd effects have been an important part of the discourse on how to best implement human papillomavirus (HPV) vaccines and prevent HPV-related diseases.

AREAS COVERED

In this paper, we review the theory of HPV vaccine herd effects derived from mathematical models, give an account of observed HPV vaccine herd effects worldwide, and examine the implications of vaccine herd effects for future cervical cancer screening efforts.

EXPERT COMMENTARY

HPV vaccine herd effects improve the cost-effectiveness of vaccinating preadolescent girls, but contribute to making gender-neutral vaccination less economically efficient. Vaccination coverage and sexual mixing patterns by age are strong determinants of herd effects. Many countries worldwide are starting to observe reductions in HPV-related outcomes likely attributable to herd effects, most notably declining anogenital warts in young men, and declining HPV-16/18 infection prevalence in young unvaccinated women. Policy makers making recommendations for cervical cancer screening will have to consider HPV vaccination coverage and herd effects, as these will affect the positive predictive value of screening and the risk of cervical cancer in unvaccinated women.

A Multiple Streams analysis of the decisions to fund gender-neutral HPV vaccination in Canada

In Canada, the human papillomavirus (HPV) vaccine is licensed and recommended for females and males. Although all Canadian jurisdictions fund school-based HPV vaccine programs for girls, only six jurisdictions fund school-based HPV vaccination for boys. The research aimed to analyze the factors that underpin government decisions to fund HPV vaccine for boys using a theoretical policy model, Kingdon's Multiple Streams framework. This approach assesses policy development by examining three concurrent, but independent, streams that guide analysis: Problem Stream, Policy Stream, and Politics Stream. Analysis from the Problem Stream highlights that males are affected by HPV-related diseases and are involved in transmitting HPV infection to their sexual partners. Policy Stream analysis makes clear that while the inclusion of males in HPV vaccine programs is suitable, equitable, and acceptable; there is debate regarding cost-effectiveness. Politics Stream analysis identifies the perspectives of six different stakeholder groups and highlights the contribution of government officials at the provincial and territorial level. Kingdon's Multiple Streams framework helps clarify the opportunities and barriers for HPV vaccine policy change. This analysis identified that the interpretation of cost-effectiveness models and advocacy of stakeholders such as citizen-advocates and HPV-affected politicians have been particularly important in galvanizing policy change.

Ecological validity of cost-effectiveness models of universal HPV vaccination: A systematic literature review

BACKGROUND

The protective (herd) effect of the selective vaccination of pubertal girls against human papillomavirus (HPV) implies a high probability that one of the two partners involved in intercourse is immunised, hence preventing the other from this sexually transmitted infection. The dynamic transmission models used to inform immunisation policy should include consideration of sexual behaviours and population mixing in order to demonstrate an ecological validity, whereby the scenarios modelled remain faithful to the real-life social and cultural context. The primary aim of this review is to test the ecological validity of the universal HPV vaccination cost-effectiveness modelling available in the published literature.

METHODS

The research protocol related to this systematic review has been registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42016034145). Eight published economic evaluations were reviewed.

RESULTS

None of the studies showed due consideration of the complexities of human sexual behaviour and the impact this may have on the transmission of HPV.

DISCUSSION

Our findings indicate that all the included models might be affected by a different degree of ecological bias, which implies an inability to reflect the natural demographic and behavioural trends in their outcomes and, consequently, to accurately inform public healthcare policy. In particular, ecological bias have the effect to over-estimate the preference-based outcomes of selective immunisation. A relatively small (15-20%) over-estimation of quality-adjusted life years (QALYs) gained with selective immunisation programmes could induce a significant error in the estimate of cost-effectiveness of universal immunisation, by inflating its incremental cost effectiveness ratio (ICER) beyond the acceptability threshold. The results modelled here demonstrate the limitations of the cost-effectiveness studies for HPV vaccination, and highlight the concern that public healthcare policy might have been built upon incomplete studies.