The potential cost-effectiveness of prophylactic human papillomavirus vaccines in Canada

Discounting health gain: a different view

At least since the Age of Enlightenment, good health has been a tenet for society. Healthy societies could learn better, work harder, improve their wealth, and live longer. Today societies focus on life expectancy, as we value long and healthy lives. As illustrated by the provision of COVID-19 vaccines first for the elderly, societies value life-saving actions. Paradoxically, health economic assessments conventionally devalue long-lasting health through the practice of discounting health benefits along with costs. However, health, with its intrinsic and instrumental characteristics, is not synonymous with money cash, a tradeable asset that devalues with time. If improving healthy life expectancy is a societal ambition, it seems counter-intuitive to value future health less as a result of an artificial mathematical construct when evaluating economically new medical interventions. In this paper, we investigate the application of discounting health in healthcare and consider paradoxical findings, especially in relation to disease prevention with vaccination. We argue that there is no economically sustainable argument to discount health gains, except for the benefit of the payer with a goal of spending less on life-saving products. If that is the objective for discounting health, there are other means to achieve the same goal in a more transparent and simpler way. From the long-term perspective of healthcare development, not discounting health gains would encourage research that values long-term effects. This in turn has the potential to benefit the investor, the payer, and the patient/consumer, improving the situation from multiple perspectives.

Updated estimate of the annual direct medical cost of screening and treatment for human papillomavirus associated disease in the United States

The annual direct medical cost attributable to human papillomavirus (HPV) in the United States over the period 2004-2007 was estimated at $9.36 billion in 2012 (updated to 2020 dollars). The purpose of this report was to update that estimate to account for the impact of HPV vaccination on HPV-attributable disease, reductions in the frequency of cervical cancer screening, and new data on the cost per case of treating HPV-attributable cancers. Based primarily on data from the literature, we estimated the annual direct medical cost burden as the sum of the costs of cervical cancer screening and follow-up and the cost of treating HPV-attributable cancers, anogenital warts, and recurrent respiratory papillomatosis (RRP). We estimated the total direct medical cost of HPV to be $9.01 billion annually over the period 2014-2018 (2020 U.S. dollars). Of this total cost, 55.0% was for routine cervical cancer screening and follow-up, 43.8% was for treatment of HPV-attributable cancer, and less than 2% was for treating anogenital warts and RRP. Although our updated estimate of the direct medical cost of HPV is slightly lower than the previous estimate, it would have been substantially lower had we not incorporated more recent, higher cancer treatment costs.

Priorities among effective clinical preventive services in British Columbia, Canada

BACKGROUND

Despite the long-standing experience of rating the evidence for clinical preventive services, the delivery of effective clinical preventive services in Canada and elsewhere is less than optimal. We outline an approach used in British Columbia to assist in determining which effective clinical preventive services are worth doing.

METHODS

We calculated the clinically preventable burden and cost-effectiveness for 28 clinical preventive services that received a 'strong or conditional (weak) recommendation for' by the Canadian Task Force on Preventive Health Care or an 'A' or 'B' rating by the United States Preventive Services Task Force. Clinically preventable burden is the total quality adjusted life years that could be gained if the clinical preventive services were delivered at recommended intervals to a British Columbia birth cohort of 40,000 individuals over the years of life that the service is recommended. Cost-effectiveness is the net cost per quality adjusted life year gained.

RESULTS

Clinical preventive services with the highest population impact and best value for money include services that address tobacco use in adolescents and adults, exclusive breastfeeding, and screening for hypertension and other cardiovascular disease risk factors followed by appropriate pharmaceutical treatment. In addition, alcohol misuse screening and brief counseling, one-time screening for hepatitis C virus infection in British Columbia adults born between 1945 and 1965, and screening for type 2 diabetes approach these high-value clinical preventive services.

CONCLUSIONS

These results enable policy makers to say with some confidence what preventive manoeuvres are worth doing but further work is required to determine the best way to deliver these services to all those eligible and to establish what supportive services are required. After all, if a clinical preventive service is worth doing, it is worth doing well.

Cost-Effectiveness of Bivalent, Quadrivalent, and Nonavalent HPV Vaccination in South Africa

BACKGROUND AND OBJECTIVES

In South Africa, the prevalence of human papillomavirus (HPV) and associated diseases, such as cervical cancer and genital warts, is among the highest in the world. This study evaluates the cost-effectiveness of bivalent, quadrivalent, and nonavalent HPV vaccination for 9- to 14-year-old girls from the South African healthcare system perspective.

METHODS

A Markov model portraying the natural HPV disease progression from high-risk infection to cervical intraepithelial neoplasia (CIN) I, CIN II/III, or cervical cancer and from low-risk infection to genital warts was built. Transition probability, utility, and efficacy data were sourced from peer-reviewed literature. Vaccination costs were calculated based on the World Health Organization (WHO) guidelines. The model was populated with a cohort of 520,000 9-year-old girls to calculate incremental cost-effectiveness ratios (ICER) in South African Rand (R) per quality-adjusted life-years (QALYs) gained for each vaccination strategy.

RESULTS

All HPV vaccination strategies dominate the no vaccine strategy. Compared with the bivalent vaccine, the nonavalent strategy increases QALYs by 0.14 and costs by R1793 (ICER: R13,013 per QALY) per person, while the quadrivalent vaccination provides -0.02 incremental QALYs and R1748 costs (ICER: -R116,397 per QALY). Consequently, at the South African willingness-to-pay threshold of R23,630 per QALY, nonavalent vaccination is the preferred strategy, with a probability of 90.2%. Scenario analysis demonstrated that results are influenced by vaccine coverage, efficacy, and duration of efficacy.

CONCLUSIONS

The introduction of nonavalent for bivalent HPV vaccination is a cost-effective intervention in South Africa. HPV vaccination should be part of a multifaceted public health strategy entailing screening, condoms, and education of all stakeholders to reduce the significant burden of sexual transmitted diseases in South Africa. Sex-neutral and catch-up vaccinations are subjects for further research.

Simplified Mathematical Modelling of Uncertainty: Cost-Effectiveness of COVID-19 Vaccines in Spain

When exceptional situations, such as the COVID-19 pandemic, arise and reliable data is not available at decision-making times, estimation using mathematical models can provide a reasonable reckoning for health planning. We present a simplified model (static but with two-time references) for estimating the cost-effectiveness of the COVID-19 vaccine. A simplified model provides a quick assessment of the upper bound of cost-effectiveness, as we illustrate with data from Spain, and allows for easy comparisons between countries. It may also provide useful comparisons among different vaccines at the marketplace, from the perspective of the buyer. From the analysis of this information, key epidemiological figures, and costs of the disease for Spain have been estimated, based on mortality. The fatality rate is robust data that can alternatively be obtained from death registers, funeral homes, cemeteries, and crematoria. Our model estimates the incremental cost-effectiveness ratio (ICER) to be 5132 € (4926–5276) as of 17 February 2021, based on the following assumptions/inputs: An estimated cost of 30 euros per dose (plus transport, storing, and administration), two doses per person, efficacy of 70% and coverage of 70% of the population. Even considering the possibility of some bias, this simplified model provides confirmation that vaccination against COVID-19 is highly cost-effective.

An economic and disease transmission model of human papillomavirus and oropharyngeal cancer in Texas

In 2017, 46,157 and 3,127 new oropharyngeal cancer (OPC) cases were reported in the U.S. and Texas, respectively. About 70% of OPC were attributed to human papillomavirus (HPV). However, only 51% of U.S. and 43.5% of Texas adolescents have completed the HPV vaccine series. Therefore, modeling the demographic dynamics and transmission of HPV and OPC progression is needed for accurate estimation of the economic and epidemiological impacts of HPV vaccine in a geographic area. An age-structured population dynamic model was developed for the U.S. state of Texas. With Texas-specific model parameters calibrated, this model described the dynamics of HPV-associated OPC in Texas. Parameters for the Year 2010 were used as the initial values, and the prediction for Year 2012 was compared with the real age-specific incidence rates in 23 age groups for model validation. The validated model was applied to predict 100-year age-adjusted incidence rates. The public health benefits of HPV vaccine uptake were evaluated by computer simulation. Compared with current vaccination program, increasing vaccine uptake rates by 50% would decrease the cumulative cases by 4403, within 100 years. The incremental cost-effectiveness ratio of this strategy was $94,518 per quality-adjusted life year (QALY) gained. Increasing the vaccine uptake rate by 50% can: (i) reduce the incidence rates of OPC among both males and females; (ii) improve the quality-adjusted life years for both males and females; (iii) be cost-effective and has the potential to provide tremendous public health benefits in Texas.

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.

Updated medical care cost estimates for HPV-associated cancers: implications for cost-effectiveness analyses of HPV vaccination in the United States

Estimates of medical care costs for cervical and other cancers associated with human papillomavirus (HPV) are higher in studies published in recent years than in studies published before 2012. The purpose of this report is (1) to review and summarize the recent cancer cost estimates and (2) to illustrate how the estimated cost-effectiveness of HPV vaccination might change when these recent cost estimates are applied. Our literature search yielded 6 studies that provided updated medical care cost estimates for 5 HPV-associated cancers. We found that applying the current cancer cost estimates had a notable impact on the estimated medical costs averted by HPV vaccination over an extended time frame (100 years), and a moderate impact on the estimated cost per quality-adjusted life year (QALY) gained by HPV vaccination. For example, for catch-up vaccination of teenagers and young adults, applying the more recent cancer costs reduced the estimated cost per QALY gained by about $12,400. The cost studies we identified in our literature review are up-to-date and based on reliable data sources from United States settings, and can inform future studies of HPV vaccination cost-effectiveness in the United States. However, careful consideration is warranted to determine the most appropriate cost values to apply.

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 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.

Revisiting assumptions about age-based mixing representations in mathematical models of sexually transmitted infections

BACKGROUND

Sexual mixing between heterogeneous population subgroups is an integral component of mathematical models of sexually transmitted infections (STIs). This study compares the fit of different mixing representations to survey data and the impact of different mixing assumptions on the predicted benefits of hypothetical human papillomavirus (HPV) vaccine strategies.

METHODS

We compared novel empirical (data-driven) age mixing structures with the more commonly-used assortative-proportionate (A-P) mixing structure. The A-P mixing structure assumes that a proportion of sexual contacts - known as the assortativity constant, typically estimated from survey data or calibrated - occur exclusively within one's own age group and the remainder mixes proportionately among all age groups. The empirical age mixing structure was estimated from the National Survey on Sexual Attitudes and Lifestyles 3 (Natsal-3) using regression methods, and the assortativity constant was estimated from Natsal-3 as well. Using a simplified HPV transmission model under each mixing assumption, we calibrated the model to British HPV16 prevalence data, then estimated the reduction in steady-state prevalence and the number of infections averted due to expanding HPV vaccination from 12- through 26-year-old females alone to 12-year-old males or 27- to 39-year-old females.

RESULTS

Empirical mixing provided a better fit to the Natsal-3 data than the best-fitting A-P structure. Using the model with empirical mixing as a reference, the model using the A-P structure often under- or over-estimated the benefits of vaccination, in one case overestimating by 2-fold the number of infections prevented due to extended female catch-up in a high vaccine uptake setting.

CONCLUSIONS

An empirical mixing structure more accurately represents sexual mixing survey data, and using the less accurate, yet commonly-used A-P structure has a notable effect on estimates of HPV vaccination benefits. This underscores the need for mixing structures that are less dependent on unverified assumptions and are directly informed by sexual behavior data.

Efficacy of a Carrageenan gel Against Transmission of Cervical HPV (CATCH): interim analysis of a randomized, double-blind, placebo-controlled, phase 2B trial

OBJECTIVES

To evaluate the efficacy of a carrageenan-based lubricant gel in reducing the risk of genital human papillomavirus (HPV) infections in women.

METHODS

We conducted a planned interim analysis of a randomized, double-blind, placebo-controlled, phase 2B trial. Women aged 18 years and older were randomly assigned (1:1) to a carrageenan-based gel or a placebo gel to be self-applied every other day for the first month and before and after each intercourse during follow-up. Assessments were performed at 0.5, 1, 3, 6, 9 and 12 months. The primary outcome was incidence of a new infection by an HPV type that was not present at baseline. Intention-to-treat analyses were performed.

RESULTS

Between January 2013 and June 2017, a total of 280 participants were randomly assigned to the carrageenan (n = 141) or the placebo (n = 139) arm. All participants were included in safety analyses, but three (1%) were excluded from efficacy analyses (HPV results unavailable for two participants in the carrageenan and one participant in the placebo arm). The median follow-up time was 9.2 months (interquartile range, 1.9-13.2 months). A total of 59 (42%) of 139 participants in the carrageenan arm and 78 (57%) of 138 participants in the placebo arm became infected by at least one new HPV type (hazard ratio = 0.64, 95% confidence interval = 0.45-0.89, p 0.009). A total of 62 (44%) of 141 participants in the carrageenan arm versus 43 (31%) of 139 participants in the placebo arm reported an adverse event (p 0.02), none of which was deemed related to the gels.

CONCLUSIONS

Our trial's interim analysis suggests that using a carrageenan-based lubricant gel can reduce the risk of genital HPV infections in women.

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.

Human Papillomavirus Vaccination Uptake in Canada: A Systematic Review and Meta-analysis

Human papillomavirus (HPV) is the most commonly sexually transmitted infection in the world and the primary cause of cervical cancer. Canada introduced publicly funded HPV vaccination programs in 2006. The objectives of this study are twofold and aim to (1) determine the levels and (2) examine the various factors influencing vaccine uptake among the general Canadian population. A literature search was conducted on seven databases, followed by screening, methodological quality review (using modified Newcastle-Ottawa Scale), and data extraction. Pooled meta-analysis and a subgroup analysis were conducted stratifying by a number of variables (age, sex, type of program, and method of payment) determined apriori. A total of 718 peer-reviewed articles were initially identified with 12 remaining after screening and underwent methodological quality review. HPV vaccination uptake in Canada varied from 12.40% (95% confidence interval [CI] 6.77–20.26) to 88.20% (95% CI 85.72–90.39). The pooled random effects model showed the HPV vaccination uptake to be 55.92% (95% CI 44.87–66.65). The subgroup analysis showed that vaccination uptake was 66.95% (95% CI 55.00–77.89) in participants ≤ 18 years as compared to 13.58% (95% CI 10.93–16.46) in participants > 18 years. Uptake for females was higher 57.23% (95% CI: 45.40–68.66) when compared to that of 47.01% (95% CI: 0.82–97.75) in males. HPV vaccine uptake among school-based programs was 69.62% (95% CI 57.27–80.68) as compared to 18.66% (95% CI 6.66–34.92) for community-based programs. Vaccination uptake for publicly funded programs was significantly higher 66.95% (95% CI 55.00–77.89) when compared to 13.58% (95% CI 10.92–16.46) for programs where participants had to pay out of pocket. To prevent infections and reduce the burden of HPV-related diseases (including cervical cancer), communities should be made aware and encouraged to vaccinate their children. There is a documented need to direct effort and focus interventions toward improving HPV vaccination uptake in Canada.

Cost-effectiveness of human papillomavirus vaccination in Germany

BACKGROUND

The aim of this study was to assess the cost-effectiveness of human papillomavirus (HPV) vaccination in addition to the current cervical cancer screening programme in Germany using a dynamic transmission model.

METHODS

Based on a mathematical model simulating the transmission dynamics and the natural history of HPV infection and associated diseases (cervical intraepithelial neoplasia, cervical cancer, and genital warts), we estimated the epidemiological and economic consequences of HPV vaccination with both the quadrivalent and bivalent vaccines. In our base case analysis, we assessed the cost-effectiveness of vaccinating 12-year-old girls with a 3-dose schedule. In sensitivity analysis, we also evaluated the use of a 2-dose schedule and assessed the impact of vaccinating boys.

RESULTS

From a health care payer perspective, incremental cost-effectiveness ratios (ICERs) of a 3-dose schedule were €34,249 per quality-adjusted life year (QALY) for the bivalent and €14,711 per QALY for the quadrivalent vaccine. Inclusion of indirect costs decreased ICERs by up to 40%. When adopting a health care payer perspective, ICERs of a 2-dose approach decreased to €19,450 per QALY for the bivalent and to €3645 per QALY for the quadrivalent vaccine. From a societal perspective, a 2-dose approach using the quadrivalent vaccine was a cost-saving strategy while using the bivalent vaccine resulted in an ICER of €13,248 per QALY. Irrespective of the perspective adopted, additional vaccination of boys resulted in ICERs exceeding €50,000 per QALY, except for scenarios with low coverage (20%) in girls.

CONCLUSIONS

Our model results suggest that routine HPV vaccination of 12-year-old girls with three doses is likely to be cost-effective in Germany. Due to the additional impact on genital warts, the quadrivalent vaccine appeared to be more cost-effective than the bivalent vaccine. A 2-dose schedule of the quadrivalent vaccine might even lead to cost savings when adopting a societal perspective. The cost-effectiveness of additional vaccination of boys was highly dependent on the coverage in girls.

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.

Clinical effectiveness and cost-effectiveness of interventions for the treatment of anogenital warts: systematic review and economic evaluation

BACKGROUND

Typically occurring on the external genitalia, anogenital warts (AGWs) are benign epithelial skin lesions caused by human papillomavirus infection. AGWs are usually painless but can be unsightly and physically uncomfortable, and affected people might experience psychological distress. The evidence base on the clinical effectiveness and cost-effectiveness of treatments for AGWs is limited.

OBJECTIVES

To systematically review the evidence on the clinical effectiveness of medical and surgical treatments for AGWs and to develop an economic model to estimate the cost-effectiveness of the treatments.

DATA SOURCES

Electronic databases (MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library databases and Web of Science) were searched from inception (or January 2000 for Web of Science) to September 2014. Bibliographies of relevant systematic reviews were hand-searched to identify potentially relevant studies. The World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov were searched for ongoing and planned studies.

REVIEW METHODS

A systematic review of the clinical effectiveness literature was carried out according to standard methods and a mixed-treatment comparison (MTC) undertaken. The model implemented for each outcome was that with the lowest deviance information criterion. A de novo economic model was developed to assess cost-effectiveness from the perspective of the UK NHS. The model structure was informed through a systematic review of the economic literature and in consultation with clinical experts. Effectiveness data were obtained from the MTC. Costs were obtained from the literature and standard UK sources.

RESULTS

Of 4232 titles and abstracts screened for inclusion in the review of clinical effectiveness, 60 randomised controlled trials (RCTs) evaluating 19 interventions were included. Analysis by MTC indicated that ablative techniques were typically more effective than topical interventions at completely clearing AGWs at the end of treatment. Podophyllotoxin 0.5% solution (Condyline(®), Takeda Pharmaceutical Company Ltd; Warticon(®) solution, Stiefel Laboratories Ltd) was found to be the most effective topical treatment evaluated. Networks for other outcomes included fewer treatments, which restrict conclusions on the comparative effectiveness of interventions. In total, 84 treatment strategies were assessed using the economic model. Podophyllotoxin 0.5% solution first line followed by carbon dioxide (CO2) laser therapy second line if AGWs did not clear was most likely to be considered a cost-effective use of resources at a willingness to pay of £20,000-30,000 per additional quality-adjusted life-year gained. The result was robust to most sensitivity analyses conducted.

LIMITATIONS

Limited reporting in identified studies of baseline characteristics for the enrolled population generates uncertainty around the comparability of the study populations and therefore the generalisability of the results to clinical practice. Subgroup analyses were planned based on type, number and size of AGWs, all of which are factors thought to influence treatment effect. Lack of data on clinical effectiveness based on these characteristics precluded analysis of the differential effects of treatments in the subgroups of interest. Despite identification of 60 studies, most comparisons in the MTC are informed by only one RCT. Additionally, lack of head-to-head RCTs comparing key treatments, together with minimal reporting of results in some studies, precluded comprehensive analysis of all treatments for AGWs.

CONCLUSIONS

The results generated by the MTC are in agreement with consensus opinion that ablative techniques are clinically more effective at completely clearing AGWs after treatment. However, the evidence base informing the MTC is limited. A head-to-head RCT that evaluates the comparative effectiveness of interventions used in clinical practice would help to discern the potential advantages and disadvantages of the individual treatments. The results of the economic analysis suggest that podophyllotoxin 0.5% solution is likely to represent a cost-effective first-line treatment option. More expensive effective treatments, such as CO2 laser therapy or surgery, may represent cost-effective second-line treatment options. No treatment and podophyllin are unlikely to be considered cost-effective treatment options. There is uncertainty around the cost-effectiveness of treatment with imiquimod, trichloroacetic acid and cryotherapy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005457.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Economic evaluation of vaccines in Canada: A systematic review

BACKGROUND

Economic evaluations should form part of the basis for public health decision making on new vaccine programs. While Canada's national immunization advisory committee does not systematically include economic evaluations in immunization decision making, there is increasing interest in adopting them. We therefore sought to examine the extent and quality of economic evaluations of vaccines in Canada.

OBJECTIVE

We conducted a systematic review of economic evaluations of vaccines in Canada to determine and summarize: comprehensiveness across jurisdictions, studied vaccines, funding sources, study designs, research quality, and changes over time.

METHODS

Searches in multiple databases were conducted using the terms "vaccine," "economics" and "Canada." Descriptive data from eligible manuscripts was abstracted and three authors independently evaluated manuscript quality using a 7-point Likert-type scale scoring tool based on criteria from the International Society for Pharmacoeconomics and Outcomes Research (ISPOR).

RESULTS

42/175 articles met the search criteria. Of these, Canada-wide studies were most common (25/42), while provincial studies largely focused on the three populous provinces of Ontario, Quebec and British Columbia. The most common funding source was industry (17/42), followed by government (7/42). 38 studies used mathematical models estimating expected economic benefit while 4 studies examined post-hoc data on established programs. Studies covered 10 diseases, with 28/42 addressing pediatric vaccines. Many studies considered cost-utility (22/42) and the majority of these studies reported favorable economic results (16/22). The mean quality score was 5.9/7 and was consistent over publication date, funding sources, and disease areas.

CONCLUSIONS

We observed diverse approaches to evaluate vaccine economics in Canada. Given the increased complexity of economic studies evaluating vaccines and the impact of results on public health practice, Canada needs improved, transparent and consistent processes to review and assess the findings of the economic evaluations of vaccines.

Sources and Characteristics of Utility Weights for Economic Evaluation of Pediatric Vaccines: A Systematic Review

BACKGROUND

Cost-effectiveness analysis of pediatric vaccines for infectious diseases often requires quality-of-life (utility) weights.

OBJECTIVE

To investigate how utility weights have been elicited and used in this context.

METHODS

A systematic review was conducted of studies published between January 1990 and July 2013 that elicited or used utility weights in cost-effectiveness analyses of vaccines for pediatric populations. The review focused on vaccines for 17 infectious diseases and is presented following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology.

RESULTS

A total of 6410 titles and abstracts and 225 full-text articles were reviewed. Of those selected for inclusion (n = 101), 15 articles described the elicitation of utility weights and 86 described economic modeling studies using utilities. Various methods were used to generate utilities, including time trade-off, contingent valuation, and willingness to pay, as well as a preference-based measure with associated value sets, such as the EuroQol five-dimensional questionnaire or the Health Utilities Index. In modeling studies, the source of utilities used was often unclear, poorly reported, or based on weak underlying evidence. We found no articles that reported on the elicitation or use of utilities in diphtheria, polio, or tetanus.

CONCLUSIONS

The scarcity of appropriate utility weights for vaccine-preventable infectious diseases in children and a lack of standardization in their use in economic assessments limit the ability to accurately assess the benefits associated with interventions to prevent infectious diseases. This is an issue that should be of concern to those making decisions regarding the prevention and treatment of infectious childhood illnesses.

Human papilloma virus vaccination: Review article and an update

Human papilloma virus (HPV) is sexually transmitted and associated with uterine cervix, vaginal, and vulvar cancers in females, oropharyngeal and anal cancer in both genders, and penile cancer in males. Moreover, genital warts are benign tumors which are HPV-related and can occur in both genders. This is a review of HPV structure, HPV infection transmission, the global impact of HPV and its associated diseases, HPV vaccines and their efficacy and safety, public acceptance of HPV vaccines, the obstacles for its acceptance and strategies to address the barriers. Cervarix (a bivalent vaccine with protection against HPV types 16 and 18) and Gardasil (a quadrivalent vaccine with protection against HPV types 6, 11, 16 and 18) are 2 recommended vaccines. The longest follow up of 9.4 years has shown efficacy and protection of the vaccine against HPV types 16 and 18. The adverse effects have been minimal and the vaccine is considered safe. Numerous studies are conducted to follow the vaccinated individuals to better understand the effect of HPV vaccine on incidence of HPV-related cancers and precancerous lesions.

Vaccination of boys or catch-up of girls above 11 years of age with the HPV-16/18 AS04-adjuvanted vaccine: where is the greatest benefit for cervical cancer prevention in Italy?

Background

Since 2007, a Human Papillomavirus (HPV) vaccination programme against cervical cancer (CC) is implemented in Italy in 11-year-old girls. The extension of HPV vaccination to young adult women, or to 11-year-old boys could further reduce the CC burden, in the latter case from indirect effect on HPV transmission. The objective of the study was to compare the potential CC cases prevention from HPV-16/18 AS04-adjuvanted vaccination of adding catch-up targeting 15- or 25-year-old girls to the addition of boys vaccination in Italy.

The models assessing the impact of these alternative vaccination strategies are usually dynamic models requiring numerous input data. Simpler models could however provide some insight into this question, as reported in the current study.

Methods

A published cohort model adapted to the Italian setting was used to estimate the potential CC reduction following different HPV vaccination strategies with a HPV-16/18 AS04-adjuvanted vaccine: vaccination of 11-year-old girls, female aged 15 or 25 years. The model assumed that the maximum benefit obtained from vaccinating boys equals the CC reduction that would result from immunisation of all non-vaccinated girls of the same age. Each cohort of 11-year-olds (either girls or boys) was assumed to include 281,000 individuals and a 70 % vaccination coverage was applied. Sensitivity analysis was performed by varying the vaccination coverage and the overlap in potential sexual contacts between vaccinated boys and girls of the same age-group.

Results

Under base case, compared with the screening-only scenario, HPV vaccination of 11-year-old girls, 15-year-old females, 25-year-old females or 11-year-old boys, would prevent 1,146, 1,082, 788 or 491 CC cases respectively. HPV vaccination of boys could result in more CC cases prevented than adding a female catch-up only in scenarios with low vaccination coverage in the primary target cohort and when combined with small overlap between vaccinated boys and girls of the same age cohort.

Conclusions

For a fixed limited additional budget allowing the inclusion of a single catch-up cohort, the extension of HPV vaccination to girls or young women instead of boys was estimated to maximise the number of CC cases prevented.

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.

A cost-effectiveness analysis of human papillomavirus vaccination of boys for the prevention of oropharyngeal cancer

BACKGROUND

Many western countries have established female human papillomavirus (HPV) vaccination programs for the prevention of cervical cancer. The quadrivalent HPV vaccine (HPV4) has proven efficacy against additional HPV-related disease in both sexes, but the cost effectiveness of male HPV vaccination remains controversial. To assess the cost effectiveness of male HPV vaccination in Canada with respect to oropharyngeal cancer (OPC), the authors performed a preliminary cost-effectiveness analysis.

METHODS

After an extensive literature review regarding HPV-related OPC in Canadian males, health care costs and clinical effectiveness estimates were obtained. A Markov model was used to compare the potential costs and effectiveness of HPV4 versus no vaccination among boys aged 12 years. A theoretical cohort based on a Canadian population of 192,940 boys aged 12 years in 2012 was assumed to apply the model. A 3-month cycle length was used with a "lifetime" time horizon. The outcome of the analysis was the incremental cost per quality-adjusted life-year (QALY). Sensitivity analyses were conducted on variables, including the vaccine uptake rate and vaccine efficacy.

RESULTS

Assuming 99% vaccine efficacy and 70% uptake, HPV4 produced 0.05 more QALYs and saved $145 Canadian dollars (CAD) per individual compared with no vaccine (QALYs and costs were discounted at 5% per year). Assuming 50% vaccine efficacy and 50% uptake, HPV4 produced 0.023 more QALYs and saved $42 CAD. The results indicated that HPV4 in males may potentially save between $8 and $28 million CAD for the theoretical cohort of 192,940 over its lifetime.

CONCLUSIONS

On the basis of this model, HPV vaccination for boys aged 12 years may be a cost-effective strategy for the prevention of OPC in Canada.

Peptidic inhibitors for in vitro pentamer formation of human papillomavirus capsid protein l1

A new 14 peptide, originating essentially from the helix 5 of HPV 16L1, illustrates an IC50 of 19.38 nM for the inhibition of HPV 16 L1 pentamer formation, which is highly efficient for targeting a specific protein segment. In addition, mechanism studies reveal that the length, sequence, and the folding of the peptide are critical factors for its inhibition. Particularly, the peptide shows similar inhibition against the pentamer formation of HPV 58L1, although it is designed specially for HPV 16 L1. This study opens a way for the development of high-efficiency, broad-spectrum inhibitors as a new class of anti-HPV agents, which could be extended to the treatment of other virus types.

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.

Comparing the cost-effectiveness of two- and three-dose schedules of human papillomavirus vaccination: a transmission-dynamic modelling study

BACKGROUND

Recent evidence suggests that two doses of HPV vaccines may be as protective as three doses in the short-term. We estimated the incremental cost-effectiveness of two- and three-dose schedules of girls-only and girls & boys HPV vaccination programmes in Canada.

METHODS

We used HPV-ADVISE, an individual-based transmission-dynamic model of multi-type HPV infection and diseases (anogenital warts, and cancers of the cervix, vulva, vagina, anus, penis and oropharynx). We conducted the analysis from the health payer perspective, with a 70-year time horizon and 3% discount rate, and performed extensive sensitivity analyses, including duration of vaccine protection and vaccine cost.

FINDINGS

Assuming 80% coverage and a vaccine cost per dose of $85, two-dose girls-only vaccination (vs. no vaccination) produced cost/quality-adjusted life-year (QALY)-gained varying between $7900-24,300. The incremental cost-effectiveness ratio of giving the third dose to girls (vs. two doses) was below $40,000/QALY-gained when: (i) three doses provide longer protection than two doses and (ii) two-dose protection was shorter than 30 years. Vaccinating boys (with two or three doses) was not cost-effective (vs. girls-only vaccination) under most scenarios investigated.

INTERPRETATION

Two-dose HPV vaccination is likely to be cost-effective if its duration of protection is at least 10 years. A third dose of HPV vaccine is unlikely to be cost-effective if two-dose duration of protection is longer than 30 years. Finally, two-dose girls & boys HPV vaccination is unlikely to be cost-effective unless the cost per dose for boys is substantially lower than the cost for girls.

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.

Differential time preferences for money and quality of life

BACKGROUND

This study provides an empirical investigation into differential time preferences between money and quality of life. Thus far, time preference investigations in health have mostly involved life-years gained and lives saved. However, the quality-adjusted life-year, which is recommended by several bodies, is a multiplicative measure of life duration and quality of life. To our knowledge, our study is the first to follow this approach specifically for quality of life.

METHODS

A questionnaire was developed to elicit time preferences for quality of life and for money, and it was distributed to a representative sample of the Dutch population. We also investigated the impact of population characteristics, such as current health state, optimistic/pessimistic future views or gender, on time preferences.

RESULTS

We found that discount rates for both money and quality of life decrease with increasing time of delay, with rates of the former being consistently at least two times higher than those of the latter. Similar trends in time preferences were observed across the subgroups, with the exception of the relatively high education subgroup.

CONCLUSION

In agreement with the results of other studies, our empirically derived discount rates are higher than the rates featured in national guidelines for health care economic assessment. Our empirical study adds to the evidence for differential discounting, both with regards to money and health, as well as in time.

Cost-effectiveness analysis of the bivalent and quadrivalent human papillomavirus vaccines from a societal perspective in Colombia

Objective

To compare costs and effectiveness of three strategies used against cervical cancer (CC) and genital warts: (i) Screening for CC; (ii) Bivalent Human Papillomavirus (HPV) 16/18 vaccine added to screening; (iii) Quadrivalent HPV 6/11/16/18 vaccine added to screening.

Methods

A Markov model was designed in order to simulate the natural history of the disease from 12 years of age (vaccination) until death. Transition probabilities were selected or adjusted to match the HPV infection profile in Colombia. A systematic review was undertaken in order to derive efficacy values for the two vaccines as well as for the operational characteristics of the cytology test. The societal perspective was used. Effectiveness was measured in number of averted Disability Adjusted Life Years (DALYS).

Results

At commercial prices reported for 2010 the two vaccines were shown to be non-cost-effective alternatives when compared with the existing screening strategy. Sensitivity analyses showed that results are affected by the cost of vaccines and their efficacy values, making it difficult to determine with certainty which of the two vaccines has the best cost-effectiveness profile. To be ‘cost-effective’ vaccines should cost between 141 and 147 USD (Unite States Dollars) per vaccinated girl at the most. But at lower prices such as those recommended by WHO or the price of other vaccines in Colombia, HPV vaccination could be considered very cost-effective.

Conclusions

HPV vaccination could be a convenient alternative for the prevention of CC in Colombia. However, the price of the vaccine should be lower for this vaccination strategy to be cost-effective. It is also important to take into consideration the willingness to pay, budgetary impact, and program implications, in order to determine the relevance of a vaccination program in this country, as well as which vaccine should be selected for use in the program.

Economic evaluation of vaccines: specificities and future challenges illustrated by recent European examples

This study reviews the current challenges in the economic evaluation of vaccines with a focus on European countries. In particular, the type of clinical evidence generally available, the impact of discounting for time preference and the use of modeling to derive valid cost-effectiveness assessments are considered. First, the characteristics of evidence for vaccines are discussed, as well as potential difficulties faced when using evidence-based medicine applied to curative drugs to interpret vaccine evidence. Then, discounting is considered and specific examples illustrating issues with different types of discounting are described, taking HPV as the example. Finally, the need for sometimes complex dynamic models for vaccines is explored, and specific types of models are reviewed, keeping into consideration the adage "complex when needed, straightforward if allowed."

Quantifying the impact of dissimilar HPV vaccination uptake among Manitoban school girls by ethnicity using a transmission dynamic model

BACKGROUND

Gardasil, a human papillomavirus (HPV) vaccine, began among grade 6 girls in Manitoba, Canada in 2008. In Manitoba, there is evidence that First Nations, Métis, and Inuit women (FNMI) have higher HPV prevalence, lower invasive cervical cancer (ICC) screening, and higher ICC incidence than all other Manitoban (AOM) women. We developed a mathematical model to assess the plausible impact of unequal vaccination coverage among school girls on future cervical cancer incidence.

METHODS

We fit model estimated HPV prevalence and ICC incidence to corresponding empirical estimates. We used the fitted model to evaluate the impact of varying levels of vaccination uptake by FNMI status on future ICC incidence, assuming cervical screening uptake among FNMI and AOM women remained unchanged.

RESULTS

Depending on vaccination coverage, estimated ICC incidence by 2059 ranged from 15% to 68% lower than if there were no vaccination. The level of cross-ethnic sexual mixing influenced the impact that vaccination rates among FNMI has on ICC incidence among AOM, and vice versa. The same level of AOM vaccination could result in ICC incidence that differs by up to 10%, depending on the level of FNMI vaccination. Similarly, the same level of FNMI vaccination could result in ICC incidence that differs by almost 40%, depending on the level of AOM vaccination.

CONCLUSIONS

If we are unable to equalize vaccination uptake among all school girls, policy makers should prepare for higher levels of cervical cancer than would occur under equal vaccination uptake.

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

BACKGROUND

The quadrivalent and bivalent human papillomavirus (HPV) vaccines are now licensed in several countries. We compared the cost-effectiveness of the HPV vaccines to provide evidence for policy decisions.

METHODS

We developed HPV-ADVISE, a multi-type individual-based transmission-dynamic model of HPV infection and disease (anogenital warts, and cervical, anogenital and oropharyngeal cancers). We calibrated the model to sexual behavior and epidemiologic data from Canada, and estimated quality-adjusted life-years (QALYs) lost and costs ($CAN 2010) from the literature. Vaccine-type efficacy was based on a systematic literature review. The analysis was performed from the healthcare provider perspective, and costs and benefits were discounted at 3%. Predictions are presented using the median [10th;90th percentiles] of simulations.

RESULTS

Under base-case assumptions (vaccinating 10-year-old girls, 80% coverage, $95/dose), using the quadrivalent and bivalent vaccines is estimated to cost $15,528 [12,056;19,140] and $20,182 [15,531;25,240] per QALY-gained, respectively. At equal price, the quadrivalent vaccine is more cost-effective than bivalent under all scenarios investigated, except when assuming longer duration of protection for the bivalent and minimal anogenital warts burden. Under base-case assumptions, the maximum additional cost per dose for the quadrivalent vaccine to remain more cost-effective than the bivalent is $32 [17;46] (using a $40,000/QALY-gained threshold). Results were most sensitive to discounting, time-horizon, differences in durations of protection and anogenital warts burden.

CONCLUSIONS

Vaccinating pre-adolescent girls against HPV is predicted to be highly cost-effective. If equally priced, the quadrivalent is the most economically desirable vaccine. However, ultimately, the most cost-effective HPV vaccine will be determined by their relative price.

Estimates of the timing of reductions in genital warts and high grade cervical intraepithelial neoplasia after onset of human papillomavirus (HPV) vaccination in the United States

BACKGROUND

The objective of this study was to estimate the number of years after onset of a quadrivalent HPV vaccination program before notable reductions in genital warts and cervical intraepithelial neoplasia (CIN) will occur in teenagers and young adults in the United States.

METHODS

We applied a previously published model of HPV vaccination in the United States and focused on the timing of reductions in genital warts among both sexes and reductions in CIN 2/3 among females. Using different coverage scenarios, the lowest being consistent with current 3-dose coverage in the United States, we estimated the number of years before reductions of 10%, 25%, and 50% would be observed after onset of an HPV vaccination program for ages 12-26 years.

RESULTS

The model suggested female-only HPV vaccination in the intermediate coverage scenario will result in a 10% reduction in genital warts within 2-4 years for females aged 15-19 years and a 10% reduction in CIN 2/3 among females aged 20-29 years within 7-11 years. Coverage had a major impact on when reductions would be observed. For example, in the higher coverage scenario a 25% reduction in CIN2/3 would be observed with 8 years compared with 15 years in the lower coverage scenario.

CONCLUSIONS

Our model provides estimates of the potential timing and magnitude of the impact of HPV vaccination on genital warts and CIN 2/3 at the population level in the United States. Notable, population-level impacts of HPV vaccination on genital warts and CIN 2/3 can occur within a few years after onset of vaccination, particularly among younger age groups. Our results are generally consistent with early reports of declines in genital warts among youth.

A comparative analysis of the epidemiological impact and disease cost-savings of HPV vaccines in France

The aim was to compare the epidemiological and economic impact of 16/18 bivalent and 6/11/16/18 quadrivalent HPV vaccination in France, considering differences in licensed outcomes, protection against non-vaccine HPV types and prevention of HPV-6/11-related diseases.

The differential impact of the two vaccines was evaluated using a published model adapted to the French setting. The target population was females aged 14–23 y and the time horizon was 100 y. A total of eight different scenarios compared vaccination impact in terms of reduction in HPV-16/18-associated carcinomas (cervical, vulvar, vaginal, anal, penile and head and neck), HPV-6/11-related genital warts and recurrent respiratory papillomatosis, and incremental reduction in cervical cancer due to potential cross-protection.

Quadrivalent vaccine was associated with total discounted cost savings ranging from EUR 544–1,020 million vs. EUR 177–538 million with the bivalent vaccination (100-y time horizon). Genital wart prevention thanks to quadrivalent HPV vaccination accounted for EUR 306–380 million savings (37–56% of costs saved). In contrast, the maximal assumed cross-protection against cervical cancer resulted in EUR 13–33 million savings (4%). Prevention of vulvar, vaginal and anal cancers accounted for additional EUR 71–89 million savings (13%).

In France, the quadrivalent HPV vaccination would result in significant incremental epidemiological and economic benefits vs. the bivalent vaccination, driven primarily by prevention of genital. The present analysis is the first in the French setting to consider the impact of HPV vaccination on all HPV diseases and non-vaccine types.

Economic analyses to support decisions about HPV vaccination in low- and middle-income countries: a consensus report and guide for analysts

Low- and middle-income countries need to consider economic issues such as cost-effectiveness, affordability and sustainability before introducing a program for human papillomavirus (HPV) vaccination. However, many such countries lack the technical capacity and data to conduct their own analyses. Analysts informing policy decisions should address the following questions: 1) Is an economic analysis needed? 2) Should analyses address costs, epidemiological outcomes, or both? 3) If costs are considered, what sort of analysis is needed? 4) If outcomes are considered, what sort of model should be used? 5) How complex should the analysis be? 6) How should uncertainty be captured? 7) How should model results be communicated? Selecting the appropriate analysis is essential to ensure that all the important features of the decision problem are correctly represented, but that the analyses are not more complex than necessary. This report describes the consensus of an expert group convened by the World Health Organization, prioritizing key issues to be addressed when considering economic analyses to support HPV vaccine introduction in these countries.

Testing a model for parental acceptance of human papillomavirus vaccine in 9- to 18-year-old girls: a theory-guided study

Gardasil is the first vaccine developed to prevent cervical cancer and other diseases caused by certain types of genital human papillomavirus in females, but little is known about parental acceptance of this vaccine. The purpose of this study was to test a model that predicts intention to vaccinate that includes constructs from the health belief model and the theory of reasoned action.

Modeling preventative strategies against human papillomavirus-related disease in developed countries

Over the last 5 years, prophylactic vaccination against human papillomavirus (HPV) in pre-adolescent females has been introduced in most developed countries, supported by modeled evaluations that have almost universally found vaccination of pre-adolescent females to be cost-effective. Studies to date suggest that vaccination of pre-adolescent males may also be cost-effective at a cost per vaccinated individual of ~US$400-500 if vaccination coverage in females cannot be increased above ~50%; but if it is possible, increasing coverage in females appears to be a better return on investment. Comparative evaluation of the quadrivalent (HPV16,18,6,11) and bivalent (HPV16,18) vaccines centers around the potential trade-off between protection against anogenital warts and vaccine-specific levels of cross-protection against infections not targeted by the vaccines. Future evaluations will also need to consider the cost-effectiveness of a next generation nonavalent vaccine designed to protect against ~90% of cervical cancers. The timing of the effect of vaccination on cervical screening programs will be country-specific and will depend on vaccination catch-up age range and coverage and the age at which screening starts. Initial evaluations suggest that if screening remains unchanged, it will be less cost-effective in vaccinated compared to unvaccinated women but, in the context of current vaccines, will remain an important prevention method. Comprehensive evaluation of new approaches to screening will need to consider the population-level effects of vaccination over time. New screening strategies of particular interest include delaying the start age of screening, increasing the screening interval and switching to primary HPV screening. Future evaluations of screening will also need to focus on the effects of disparities in screening and vaccination uptake, the potential effects of vaccination on screening participation, and the effects of imperfect compliance with screening recommendations. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Human papilloma virus vaccination programs reduce health inequity in most scenarios: a simulation study

BACKGROUND

The global and within-country epidemiology of cervical cancer exemplifies health inequity. Public health programs may reduce absolute risk but increase inequity; inequity may be further compounded by screening programs. In this context, we aimed to explore what the impact of human papillomavirus (HPV) vaccine might have on health equity allowing for uncertainty surrounding the long-term effect of HPV vaccination programs.

METHODS

A simple static multi-way sensitivity analysis was carried out to compare the relative risk, comparing after to before implementation of a vaccination program, of infections which would cause invasive cervical cancer if neither prevented nor detected, using plausible ranges of vaccine effectiveness, vaccination coverage, screening sensitivity, screening uptake and changes in uptake.

RESULTS

We considered a total number of 3,793,902 scenarios. In 63.9% of scenarios considered, vaccination would lead to a better outcome for a population or subgroup with that combination of parameters. Regardless of vaccine effectiveness and coverage, most simulations led to lower rates of disease.

CONCLUSIONS

If vaccination coverage and screening uptake are high, then communities are always better off with a vaccination program. The findings highlight the importance of achieving and maintaining high immunization coverage and screening uptake in high risk groups in the interest of health equity.

Cost-effectiveness of adding vaccination with the AS04-adjuvanted human papillomavirus 16/18 vaccine to cervical cancer screening in Hungary

BACKGROUND

The cervical cancer screening program implemented in Hungary to date has not been successful. Along with screening, vaccination is an effective intervention to prevent cervical cancer. The aim of this study was to assess the cost-effectiveness of adding vaccination with the human papillomavirus 16/18 vaccine to the current cervical cancer screening program in Hungary.

METHODS

We developed a cohort simulation state-transition Markov model to model the life course of 12-year-old girls. Eighty percent participation in the HPV vaccination program at 12 years of age was assumed. Transitional probabilities were estimated using data from the literature. Local data were used regarding screening participation rates, and the costs were estimated in US $. We applied the purchasing power parity exchange rate of 129 HUF/$ to the cost data. Only direct health care costs were considered. We used a 3.7% discount rate for both the cost and quality-adjusted life years (QALYs). The time horizon was 88 years.

RESULTS

Inclusion of HPV vaccination at age 12 in the cervical cancer prevention program was predicted to be cost-effective. The incremental cost-effectiveness ratio (ICER) of adding HPV vaccination to the current national cancer screening program was estimated to be 27 588 $/QALY. The results were sensitive to the price of the vaccine, the discount rate, the screening participation rate and whether herd immunity was taken into account.

CONCLUSIONS

Our modeling analysis showed that the vaccination of 12-year-old adolescent girls against cervical cancer with the AS04-adjuvanted human papillomavirus 16/18 vaccine would be a cost-effective strategy to prevent cervical cancer in Hungary.

Population-level impact of the bivalent, quadrivalent, and nonavalent human papillomavirus vaccines: a model-based analysis

BACKGROUND

Bivalent and quadrivalent human papillomavirus (HPV) vaccines are now licensed in several countries. Furthermore, clinical trials examining the efficacy of a nonavalent vaccine are underway. We aimed to compare the potential population-level effectiveness of the bivalent, quadrivalent, and candidate nonavalent HPV vaccines.

METHODS

We developed an individual-based, transmission-dynamic model of HPV infection and disease in a population stratified by age, gender, sexual activity, and screening behavior. The model was calibrated to highly stratified sexual behavior, HPV epidemiology, and cervical screening data from Canada.

RESULTS

Under base case assumptions, vaccinating 12-year-old girls (70% coverage) with the bivalent (quadrivalent) vaccine is predicted to reduce the cumulative incidence of anogenital warts (AGWs) by 0.0% (72.1%), diagnosed cervical intraepithelial neoplasia lesions 2 and 3 (CIN2 and -3) by 51.0% (46.1%), and cervical squamous cell carcinoma (SCC) by 31.9% (30.5%), over 70 years. Changing from a bivalent (quadrivalent) to a nonavalent vaccine is predicted to reduce the cumulative number of AGW episodes by an additional 66.7% (0.0%), CIN2 and -3 episodes by an additional 9.3% (12.5%), and SCC cases by an additional 4.8% (6.6%) over 70 years. Differences in predicted population-level effectiveness between the vaccines were most sensitive to duration of protection and the time horizon of analysis. The vaccines produced similar effectiveness at preventing noncervical HPV-related cancers.

CONCLUSIONS

The bivalent vaccine is expected to be slightly more effective at preventing CIN2 and -3 and SCC in the longer term, whereas the quadrivalent vaccine is expected to substantially reduce AGW cases shortly after the start of vaccination programs. Switching to a nonavalent vaccine has the potential to further reduce precancerous lesions and cervical cancer.

Modeling the impact of the difference in cross-protection data between a human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine and a human papillomavirus (HPV)-6/11/16/18 vaccine in Canada

Background

In Canada, two vaccines that have demonstrated high efficacy against infection with human papillomavirus (HPV) types −16 and −18 are available. The HPV-6/11/16/18 vaccine provides protection against genital warts (GW) while the HPV-16/18 vaccine may provide better protection against other oncogenic HPV types. In this analysis, the estimated clinical and economic benefit of each of these vaccines was compared in the Canadian setting.

Methods

A Markov model of the natural history of HPV infection among women, cervical cancer (CC) and GW was used to estimate the impact of vaccinating a cohort of 100,000 12-year-old females on lifetime outcomes and healthcare system costs (no indirect benefit in males included). A budget impact model was used to estimate the impact of each vaccine by province.

Results

In the base case, vaccination with the HPV-16/18 vaccine was predicted to prevent 48 additional CC cases, and 16 additional CC deaths, while vaccination with the HPV-6/11/16/18 vaccine was predicted to prevent 6,933 additional GW cases. Vaccination with the HPV-16/18 vaccine was estimated to save 1 additional discounted quality adjusted life year (QALY) at an overall lower lifetime cost to the healthcare system compared to the HPV-6/11/16/18 vaccine (assuming vaccine price parity). In sensitivity analyses, the HPV-6/11/16/18 vaccine was associated with greater QALYs saved when the cross-protection efficacy of the HPV-16/18 vaccine was reduced, or the burden of GW due to HPV-6/11 was increased. In most scenarios with price parity, the lifetime healthcare cost of the strategy with the HPV-16/18 vaccine was predicted to be lower than the HPV-6/11/16/18 vaccine. In the probabilistic sensitivity analyses, the HPV-16/18 vaccine provided more QALY benefit than the HPV-6/11/16/18 vaccine in 49.2% of scenarios, with lower relative lifetime costs in 83.5% of scenarios.

Conclusions

Overall, the predicted lifetime healthcare costs and QALYs saved by implementing each of the vaccines are similar. Vaccination with the HPV-16/18 vaccine is expected to be associated with reduced CC disease morbidity and mortality compared to vaccination with the HPV-6/11/16/18 vaccine. Differences in these outcomes depend on the extent of cervical disease prevented by cross-protection and the burden of GW caused by HPV-6/11.

Cross-protective efficacy of two human papillomavirus vaccines: a systematic review and meta-analysis

BACKGROUND

The extent of cross-protection is a key element in the choice of human papillomavirus (HPV) vaccine to use in vaccination programmes. We compared the cross-protective efficacy of the bivalent vaccine (HPV 16 and 18; Cervarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) and quadrivalent vaccine (HPV 6, 11, 16, and 18; Gardasil, Merck, Whitehouse Station, NJ, USA) against non-vaccine type HPVs.

METHODS

We searched Medline and Embase databases, conference abstracts, and manufacturers' websites for randomised clinical trials assessing the efficacy of bivalent and quadrivalent vaccines against persistent infections (lasting ≥6 months) and cervical intraepithelial neoplasia (CIN) associated with the non-vaccine type HPVs (types 31, 33, 45, 52, and 58). We included studies of participants who were HPV DNA negative before vaccination for all HPV types assessed. We assessed heterogeneity in vaccine efficacy estimates between trials with I(2) and χ(2) statistics.

FINDINGS

We identified two clinical trials (Females United to Unilaterally Reduce Endo/Ectocervical Disease [FUTURE] I and II) of the quadrivalent vaccine and three (Papilloma Trial Against Cancer In Young Adults [PATRICIA], HPV007, and HPV-023) of the bivalent vaccine. Analysis of the most comparable populations (pooled FUTURE I/II data vs PATRICIA) suggested that cross-protective vaccine efficacy estimates against infections and lesions associated with HPV 31, 33, and 45 were usually higher for the bivalent vaccine than the quadrivalent vaccine. Vaccine efficacy in the bivalent trial was higher than it was in the quadrivalent trial against persistent infections with HPV 31 (77·1% [95% CI 67·2 to 84·4] for bivalent vaccine vs 46·2% [15·3 to 66·4] for quadrivalent vaccine; p=0·003) and HPV 45 (79·0% [61·3 to 89·4] vs 7·8% [-67·0 to 49·3]; p=0·0003), and against CIN grade 2 or worse associated with HPV 33 (82·3% [53·4 to 94·7] vs 24·0% [-71·2 to 67·2]; p=0·02) and HPV 45 (100% [41·7 to 100] vs -51·9% [-1717·8 to 82·6]; p=0·04). We noted substantial heterogeneity between vaccine efficacy in bivalent trials against persistent infections with HPV 31 (I(2)=69%, p=0·04) and HPV 45 (I(2)=70%, p=0·04), with apparent reductions in cross-protective efficacy with increased follow-up.

INTERPRETATION

The bivalent vaccine seems more efficacious against non-vaccine HPV types 31, 33, and 45 than the quadrivalent vaccine, but the differences were not all significant and might be attributable to differences in trial design. Efficacy against persistent infections with types 31 and 45 seemed to decrease in bivalent trials with increased follow-up, suggesting a waning of cross-protection; more data are needed to establish duration of cross-protection.

FUNDING

Public Health Agency of Canada.

American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer

An update to the American Cancer Society (ACS) guideline regarding screening for the early detection of cervical precancerous lesions and cancer is presented. The guidelines are based on a systematic evidence review, contributions from six working groups, and a recent symposium co-sponsored by the ACS, American Society for Colposcopy and Cervical Pathology (ASCCP), and American Society for Clinical Pathology (ASCP), which was attended by 25 organizations. The new screening recommendations address age-appropriate screening strategies, including the use of cytology and high-risk human papillomavirus (HPV) testing, follow-up (e.g., management of screen positives and screening interval for screen negatives) of women after screening, age at which to exit screening, future considerations regarding HPV testing alone as a primary screening approach, and screening strategies for women vaccinated against HPV16/18 infections.

The cost effectiveness of human papillomavirus vaccines: a systematic review

INTRODUCTION

Human papillomavirus (HPV) is one of the world's most common sexually transmitted infections, and has been associated with a number of cervical and non-cervical diseases, including cancer. HPV vaccines have been licensed for use in females for some time, but the quadrivalent vaccine has only recently become licensed for use in males. Many countries have adopted a vaccination programme for adolescent females based on results of cost-effectiveness analyses. However, given the new indications for use of the vaccine in males, decision makers require information on the cost effectiveness of vaccinating males in order to make policy decisions on whether or not to fund such programmes.

OBJECTIVE

Our objective was to conduct a qualitative systematic review to update a previously conducted review of HPV vaccine studies.

METHODS

Articles were obtained from an extensive literature search to determine the cost effectiveness of implementing an HPV vaccination programme with routine cervical cancer screening. A total of 29 studies were included in this review. Seventeen of the included articles looked only at cervical disease outcomes, and 12 studies also included non-cervical disease outcomes. Four studies explored the economic impact of vaccinating both boys and girls. One study focused on a population of men who have sex with men (MSM).

RESULTS

While different model structures, input parameters and baseline assumptions were used, the consistent message in studies that focused on female-only vaccination programmes was that routine vaccination of females is cost effective compared with cervical cancer screening alone.

DISCUSSION

Based on the currently available literature, it appears that the addition of boys to a vaccination programme generally exceeds traditional cost-effectiveness thresholds. The MSM population represents a potential additional target for routine HPV vaccination; however, more cost-effectiveness studies are required before making such a policy change.

On discounting of health gains from human papillomavirus vaccination: effects of different approaches

OBJECTIVES

Discounting has long been a matter of controversy in the field of health economic evaluations. How to weigh future health effects has resulted in ongoing discussions. These discussions are imminently relevant for health care interventions with current costs but future benefits. Different approaches to discount health effects have been proposed. In this study, we estimated the impact of different approaches for discounting health benefits of human papillomavirus (HPV) vaccination.

METHODS

An HPV model was used to estimate the impact of different discounting approaches on the present value of health effects. For the constant discount approaches, we varied the discount rate for health effects ranging from 0% to 4%. Next, the impact of relevant alternative discounting approaches was estimated, including hyperbolic, proportional, stepwise, and time-shifted discounting.

RESULTS

The present value of health effects gained through HPV vaccination varied strongly when varying discount rates and approaches. The application of the current Dutch guidelines resulted in a present value of health effects that was eight or two times higher than that produced when using the proportional discounting approach or when using the internationally more common 4% discount rate for health effects, respectively. Obviously, such differences translate into large variations in corresponding incremental cost-effectiveness ratios.

CONCLUSION

The exact discount rate and approach chosen in an economic evaluation importantly impact the projected value of health benefits of HPV vaccination. Investigating alternative discounting approaches in health-economic analysis is important, especially for vaccination programs yielding health effects far into the future. Our study underlines the relevance of ongoing discussions on how and at what rates to discount.

American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer

An update to the American Cancer Society (ACS) guideline regarding screening for the early detection of cervical precancerous lesions and cancer is presented. The guidelines are based on a systematic evidence review, contributions from 6 working groups, and a recent symposium cosponsored by the ACS, the American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology, which was attended by 25 organizations. The new screening recommendations address age-appropriate screening strategies, including the use of cytology and high-risk human papillomavirus (HPV) testing, follow-up (eg, the management of screen positives and screening intervals for screen negatives) of women after screening, the age at which to exit screening, future considerations regarding HPV testing alone as a primary screening approach, and screening strategies for women vaccinated against HPV16 and HPV18 infections.