Economic evaluation of human papillomavirus vaccination in the United Kingdom

Information needs of ethnically diverse, vaccine-hesitant parents during decision-making about the HPV vaccine for their adolescent child: a qualitative study

BACKGROUND

The English schools-based human papillomavirus (HPV) vaccination programme has the potential to eliminate HPV-related cancers if high uptake is achieved. However, unmet information needs among some parents may contribute to persisting lower uptake among minority ethnic groups. Through this study we aimed to understand the information needs of vaccine-hesitant, ethnically diverse parents during decision-making about the HPV vaccine for their adolescent child, to inform the future development of tailored communication materials.

METHODS

Recruitment was facilitated thorough healthcare and community organisations within London and the South West of England. Semi-structured interviews took place between April and August 2023. Thematic analysis was undertaken, assisted by NVivo software.

RESULTS

Of the 29 parents interviewed, the majority were mothers (79%), belonged to a minority ethnic group (88%), and had an adolescent child unvaccinated against HPV (72%). Five of the interviews were undertaken in the participants' primary language with translation support. Most parents interviewed had limited knowledge about the HPV vaccine and appeared conflicted as to whether vaccines could offer benefits to health. Misunderstanding around the potential of developing serious side-effects (e.g. fertility issues, developing cancer) were factors that could negatively impact decision-making by parents. Stigma associated with the sexual transmissibility of HPV did not always negatively impact decision-making. However, some parents chose not to vaccinate on the basis of perceptions of low risk and a preference to provide education about sexual behaviours to their adolescent child.

CONCLUSIONS

Tailoring communication materials to address misunderstandings could support informed decision-making by vaccine hesitant parents for their adolescent children to be vaccinated against HPV. Future communication materials about the HPV vaccine should highlight the benefits of protection against cancer to increase parents' motivation for protect their adolescent child; provide accurate convincing information in relation to the excellent safety profile; and emphasise the importance of providing HPV vaccine at the recommended age, all alongside communicating the universality and commonality of HPV infection.

TRIAL REGISTRATION

N/A.

The impact of over ten years of HPV vaccination in England: Surveillance of type-specific HPV in young sexually active females

INTRODUCTION

The UK national human papillomavirus (HPV) vaccination programme was introduced in 2008 using the bivalent HPV16/18 vaccine, changing to the quadrivalent HPV6/11/16/18 vaccine from 2012. We provide an analysis of type-specific HPV prevalence in young sexually active females in England to end 2020 (when the first routinely HPV vaccinated females were reaching 25 years of age and entering the National Health Service Cervical Screening Programme), showing the impact of over ten years of high coverage HPV vaccination.

METHODS

Residual vulvovaginal swabs (VVS) were collected from 16 to 24 year old women attending for chlamydia screening between 2010 and 2020, anonymised and tested for type-specific HPV DNA. Trends in vaccine and non-vaccine HPV type prevalence were compared over time and association with vaccination coverage was evaluated within the post-vaccination period.

RESULTS

A total of 21,168 eligible VVS specimens were tested for HPV DNA. The prevalence of HPV16/18 in sexually active 16-18 year old females who were offered vaccination aged 12-13 years was <1% in the most recent years tested, compared to over 15% prior to the vaccination programme in 2008. The magnitude of these decreases also suggests reduced transmission is offering some herd protection to unvaccinated females. HPV31/33/45 prevalence also steadily decreased, providing evidence of cross-protection. HPV6/11 prevalence remained stable during the bivalent vaccine period, with more recent declines, as expected due to the use of the quadrivalent vaccine. There has been no substantive increase in the prevalence of other high-risk (HR) HPV types.

DISCUSSION

More than ten years of high coverage HPV vaccination in adolescent females in England has delivered dramatic declines in the prevalence of HPV vaccine-types and closely related HPV types in females in the vaccine eligible age group, and no indication of type replacement. These findings should enable confidence in planning for cervical screening of these females, and in predicting declines in HPV-related cancers.

Maximizing the cost-effectiveness of cervical screening in the context of routine HPV vaccination by optimizing screening strategies with respect to vaccine uptake: a modeling analysis

BACKGROUND

Regarding primary and secondary cervical cancer prevention, the World Health Organization proposed the cervical cancer elimination strategy that requires countries to achieve 90% uptake of human papillomavirus (HPV) vaccines and 70% screening uptake. The optimal cervical screening strategy is likely different for unvaccinated and vaccinated cohorts upon national HPV immunization. However, health authorities typically only provide a one-size-fits-all recommendation for the general population. We aimed to evaluate the cost-effectiveness for determining the optimal screening strategies for vaccinated and unvaccinated cohorts.

METHODS

We considered the women population in Hong Kong which has a unique HPV infection and cervical cancer epidemiology compared to other regions in China and Asia. We used mathematical models which comprise a deterministic age-structured compartmental dynamic component and a stochastic individual-based cohort component to evaluate the cost-effectiveness of screening strategies for cervical screening. Following the recommendations in local guidelines in Hong Kong, we considered strategies that involved cytology, HPV testing, or co-testing as primary cervical screening. We also explored the impacts of adopting alternative de-intensified strategies for vaccinated cohorts. The 3-year cytology screening was used as the base comparator while no screening was also considered for vaccinated cohorts. Women's lifetime life years, quality-adjusted life years, and costs of screening and treatment were estimated from the societal perspective based on the year 2022 and were discounted by 3% annually. Incremental cost-effectiveness ratios (ICERs) were compared to a willingness to pay (WTP) threshold of one gross domestic product per capita (US $47,792). Probabilistic and one-way sensitivity analyses were conducted.

RESULTS

Among unvaccinated cohorts, the strategy that adds reflex HPV to triage mild cytology abnormality generated more life years saved than cytology-only screening and could be a cost-effective alternative. Among vaccinated cohorts, when vaccine uptake was 85% (based on the uptake in 2022), all guideline-based strategies (including the cytology-only screening) had ICERs above the WTP threshold when compared with no screening if the vaccine-induced protection duration was 20 years or longer. Under the same conditions, HPV testing with genotyping triage had ICERs (compared with no screening) below the WTP threshold if the routine screening interval was lengthened to 10 and 15 years or screening was initiated at ages 30 and 35 years.

CONCLUSIONS

HPV testing is a cost-effective alternative to cytology for vaccinated cohorts, and the associated optimal screening frequency depends on vaccine uptake. Health authorities should optimize screening recommendations by accounting for population vaccine uptake.

Atypical glandular cells and development of cervical cancer: Population-based cohort study

The effect of cervical screening on cervical adenocarcinoma has been variable, possibly because the risk associated with the precursor atypical glandular cells (AGC) is not well known. A cohort of all 885 women in the capital region of Sweden with AGC, a concomitant human papillomavirus (HPV) analysis, and a histopathology was followed until 2019. Cumulative incidence proportions of cervical intraepithelial lesion grade 3 or worse (CIN3+) by HPV type was determined by 1-Kaplan-Meier estimates. Hazard ratios (HR) for CIN3+ or for invasive cancer were estimated with Cox regression. After 2 years of follow-up, the cumulative incidence proportions of CIN3+ were 80% (95% confidence interval [CI]: 74-86%), 58% (95% CI: 50-60%) and 10% (95% CI: 5-18%) among HPV16/18 positive, "other HPV" positive and HPV-negative women, respectively. Among the 300 women with HPV16/18 positive AGC, 217 developed CIN3+ of which 35 were invasive cervical cancer. The 2-year cumulative invasive cancer risk for HPV16/18 positive AGC was 17% (95% CI: 12-24%). Primary HPV-screening had a similar yield of CIN3+ as cytology screening, albeit HPV-negative AGC is by design not detected by HPV screening. Among 241 women with HPV-negative AGC, 11 developed CIN3+ mostly after clinically indicated samples. We found no significant risk differences depending on age or sampling indication. The low CIN3+ risk after HPV-negative AGC implies safety of primary HPV screening. The high risk of invasive cervical cancer after HPV16/18 positive AGC implies that management of this finding is a priority in cervical screening.

Stated preferences for human papillomavirus vaccination for adolescents in selected communities in Ibadan, Southwest Nigeria: A discrete choice experiment

Administration of the human papillomavirus (HPV) vaccine in early adolescence is effective in preventing cervical cancer, a common cancer in sub-Saharan Africa. Nigeria is in the pre-introduction era of the HPV vaccine. Understanding the preferences of the population for the vaccine can help design the HPV immunization program to ensure high uptake of the vaccine. This study explored the preferences for the HPV vaccine among stakeholders in selected communities in Ibadan, Nigeria. A discrete choice experiment survey based on six attributes of the HPV vaccine (which were the number of doses, the efficacy of the vaccine, cost of the vaccine, location of the service point, other benefits of the vaccine apart from prevention of cervical cancer and the odds of a side effect from the vaccine) was carried out in five communities. Data were analyzed using conditional and mixed logit models. Seven hundred community members were recruited, 144 (20.7%) were adolescents and 248 (35.4%) were males. In line with expectations, respondents preferred vaccines with higher efficacy, less severe side effects and lower costs. Preference heterogeneity was identified for adolescents that were less price-sensitive and other community members who were less likely to prefer using schools as the service point. The high socioeconomic class preferred a vaccine that also prevents genital warts. There were variabilities in the preferences for the attributes of the HPV vaccine in the study communities. These variabilities need to be considered in the introduction of the HPV vaccine to ensure high uptake of the vaccine.

Assessing the Health and Economic Outcomes of a 9-Valent HPV Vaccination Program in the United Kingdom

Background: The United Kingdom (UK) switched from using the 4-valent human papillomavirus (HPV) vaccine (Gardasil®) to the 9-valent vaccine (Gardasil 9®) in 2021. Objective: To estimate and compare the health and economic outcomes of 2 HPV vaccination programs in the UK targeting girls and boys aged 12-13 years from the perspective of the UK National Health Service. The 2 vaccination strategies were (1) universal vaccination 4-valent (UV4V), using the 4-valent HPV vaccine (4vHPV), and (2) universal vaccination 9-valent (UV9V), using the 9-valent HPV vaccine (9vHPV). Methods: A deterministic heterosexual compartmental disease transmission model was used to track health and economic outcomes over a 100-year time horizon. Outcomes were discounted at an annual rate of 3.5% and 1.5%. All costs were adjusted to 2020 British pounds (£). Health outcomes were measured in quality-adjusted life-years (QALYs), and the summary results were presented as incremental cost-effectiveness ratios (£/QALY gained) when comparing UV4V with UV9V. Results: Using the same vaccine coverage for both programs, the total cumulative cases of HPV-related health outcomes tracked over the 100-year horizon indicated that the relative number of cases averted (UV9V vs UV4V) ranged from 4% (anal male cancers and deaths) to 56% (cervical intraepithelial neoplasia [CIN1]). Assuming that 9vHPV cost £15.18 more than 4vHPV (a cost differential based on discounted list prices), the estimated incremental cost-effectiveness ratio was £8600/QALY gained when discounted at 3.5%, and £3300/QALY gained when discounted at 1.5%. The estimated incremental cost-effectiveness ratios from the sensitivity analyses remained <£28000/QALY over a wide range of parameter inputs and demonstrated that disease utilities, discount rate, and vaccine efficacy were the 3 most influential parameters. Discussion: Consistent with other published studies, the results from this study found that the 9vHPV vaccine prevented a substantial number of cases when compared with the 4vHPV vaccine and was highly cost-effective. Conclusions: These results demonstrate that replacing universal 4vHPV with 9vHPV can prevent a substantial additional number of HPV-related cases/deaths (in both women and men) and remain cost-effective over a range of 9vHPV price premiums.

Parental intention to vaccinate adolescents with HPV vaccine in selected communities in Ibadan, Southwest Nigeria: an application of Integrated Behavioral Model

Parents have important roles to play for adolescents to get the human papillomavirus (HPV) vaccine, an effective measure in the prevention of cervical and other HPV-related cancers. It is important to understand the intention of parents to have their adolescents vaccinated for optimal uptake of the vaccine in Nigeria. This study investigated the intention of parents in five selected communities to get their adolescents vaccinated with HPV vaccine in Ibadan, Nigeria using the Integrated Behavioral Model (IBM). Cross sectional study design was employed and 678 parents were interviewed. Pearson correlation, chi-square test and multiple regression were used for data analysis at α = 0.05. Mean age of the parents was 42.5 ± 10.0 years and 230(33.9%) were males. Almost all of the parents (96.8%) had the intention to vaccinate their adolescents with HPV vaccine. This intention was significantly correlated with experiential attitude (r = 0.74, p = <.01), instrumental attitude (r = 0.33, p = <.01), injunctive norm (r = 0.39, p = <.01), descriptive norm (r = 0.32, p = <.01), perceived control (r = 0.32, p = <.01) and self-efficacy (r = 0.46, p ≤ .01). A higher proportion of parents older than 65 years significantly had no intention to vaccinate their adolescents with HPV vaccine. Intention to vaccinate adolescents with HPV vaccine was predicted by experiential attitude (OR = 0.88, 95% CI: 0.80-0.95), personal agency (OR = 0.22, 95% CI: 0.15-0.29) and injunctive norm (OR = 0.08, 95% CI: 0.02-0.13). Parental intention to vaccinate adolescents with HPV vaccine was high among the parents in this study. The reluctance of older parents about HPV vaccine for adolescents requires further investigation.

Economic implications of FDA platelet bacterial guidance compliance options: Comparison of single-step strategies

BACKGROUND

Bloodborne pathogens pose a major safety risk in transfusion medicine. To mitigate the risk of bacterial contamination in platelet units, FDA issues updated guidance materials on various bacterial risk control strategies (BRCS). This analysis presents results of a budget impact model updated to include 5- and 7-day pathogen reduced (PR) and large volumed delayed sampling (LVDS) BRCS.

STUDY DESIGN AND METHODS

Model base-case parameter inputs were based on scientific literature, a survey distributed to 27 US hospitals, and transfusion experts' opinion. The outputs include hospital budget and shelf-life impacts for 5- and 7-day LVDS, and 5- and 7-day PR units under three different scenarios: (1) 100% LVDS, (2) 100% PR, and (3) mix of 50% LVDS - and 50% PR.

RESULTS

Total annual costs from the hospital perspective were highest for 100% LVDS platelets (US$2.325M) and lowest for 100% PR-7 units (US$2.170M). Net budget impact after offsetting annual costs by outpatient reimbursements was 5.5% lower for 5-day PR platelets as compared to 5-day LVDS (US$1.663 vs. US$1.760M). A mix of 7-day LVDS and 5-day PR platelets had net annual costs that were 1.3% lower than for 100% 7-day LVDS, but 1.3% higher than for 100% 5-day PR. 7-day PR platelets had the longest shelf life (4.63 days), while 5-day LVDS had the shortest (2.00 days).

DISCUSSION

The model identifies opportunities to minimize transfusion center costs for 5- and 7-day platelets. Budget impact models such as this are important for understanding the financial implications of evolving FDA guidance and new platelet technologies.

How to Prevent Vaccines Falling Victim to Their Own Success: Intertemporal Dependency of Incidence Levels on Indirect Effects in Economic Reevaluations

OBJECTIVES

Incremental cost-effectiveness analyses may inform the optimal choice of healthcare interventions. Nevertheless, for many vaccines, benefits fluctuate with incidence levels over time. Reevaluating a vaccine after it has successfully decreased incidences may eventually cause a disease resurgence if switching to a vaccine with lower indirect benefits. Decisions may successively alternate between vaccines alongside repeated rises and falls in incidence and when indirect effects from historic use are ignored. Our suggested proposal aims to prevent suboptimal decision making.

METHODS

We used a conceptual model of demand to illustrate alternating decisions between vaccines because of time-varying levels of indirect effects. Similar to the concept of subsidies, we propose internalizing the indirect effects achievable with vaccines. In a case study over 60 years, we simulated a hypothetical 10-year reevaluation of 2 oncogenic human papillomavirus vaccines, of which only 1 protects additionally against anogenital warts.

RESULTS

Our case study showed that the vaccine with additional warts protection is initially valued higher than the vaccine without additional warts protection. After 10 years, this differential decreases because of declines in warts incidence, which supports switching to the nonwarts vaccine that causes a warts resurgence eventually. Instead, pricing the indirect effects separately supports continuing with the warts vaccine.

CONCLUSIONS

Ignoring how the observed incidences depend on the indirect effects achieved with a particular vaccine may lead to repeated changes in vaccines at successive reevaluations, with unintended resurgences, economic inefficiencies, and eroding vaccine confidence. We propose internalizing indirect effects to prevent vaccines falling victim to their own success.

An Introduction to the Main Types of Economic Evaluations Used for Informing Priority Setting and Resource Allocation in Healthcare: Key Features, Uses, and Limitations

Economic evidence is increasingly being used for informing health policies. However, the underlining principles of health economic analyses are not always fully understood by non-health economists, and inappropriate types of analyses, as well as inconsistent methodologies, may be being used for informing health policy decisions. In addition, there is a lack of open access information and methodological guidance targeted to public health professionals, particularly those based in low- and middle-income country (LMIC) settings. The objective of this review is to provide a comprehensive and accessible introduction to economic evaluations for public health professionals with a focus on LMIC settings. We cover the main principles underlining the most common types of full economic evaluations used in healthcare decision making in the context of priority setting (namely cost-effectiveness/cost-utility analyses, cost-benefit analyses), and outline their key features, strengths and weaknesses. It is envisioned that this will help those conducting such analyses, as well as stakeholders that need to interpret their output, gain a greater understanding of these methods and help them select/distinguish between the different approaches. In particular, we highlight the need for greater awareness of the methods used to place a monetary value on the health benefits of interventions, and the potential for such estimates to be misinterpreted. Specifically, the economic benefits reported are typically an approximation, summarising the health benefits experienced by a population monetarily in terms of individual preferences or potential productivity gains, rather than actual realisable or fiscal monetary benefits to payers or society.

Bayesian versus Empirical Calibration of Microsimulation Models: A Comparative Analysis

Calibration of a microsimulation model (MSM) is a challenging but crucial step for the development of a valid model. Numerous calibration methods for MSMs have been suggested in the literature, most of which are usually adjusted to the specific needs of the model and based on subjective criteria for the selection of optimal parameter values. This article compares 2 general approaches for calibrating MSMs used in medical decision making, a Bayesian and an empirical approach. We use as a tool the MIcrosimulation Lung Cancer (MILC) model, a streamlined, continuous-time, dynamic MSM that describes the natural history of lung cancer and predicts individual trajectories accounting for age, sex, and smoking habits. We apply both methods to calibrate MILC to observed lung cancer incidence rates from the Surveillance, Epidemiology and End Results (SEER) database. We compare the results from the 2 methods in terms of the resulting parameter distributions, model predictions, and efficiency. Although the empirical method proves more practical, producing similar results with smaller computational effort, the Bayesian method resulted in a calibrated model that produced more accurate outputs for rare events and is based on a well-defined theoretical framework for the evaluation and interpretation of the calibration outcomes. A combination of the 2 approaches is an alternative worth considering for calibrating complex predictive models, such as microsimulation models.

Incidence, Persistence, and Factors Associated With HPV Infection Among Male Adolescents With and Without Perinatally Acquired HIV Infection

BACKGROUND

Infection with high-risk human papillomavirus (HR-HPV) has been shown to be more prevalent and persistent in female adolescents with HIV. However, data among male adolescents with perinatally acquired HIV (PHIV) are limited.

SETTING

We investigated the incidence and persistence of HR-HPV in anogenital compartments and associated factors among PHIV in comparison to HIV-uninfected (HU) male adolescents in Thailand.

METHODS

PHIV and HU males aged 12-24 years were enrolled. At baseline and 3 subsequent annual visits, specimens from the scrotum, penis, and anal area were obtained for HPV and other testing.

RESULTS

From June 2013 to October 2017, 49 PHIV and 47 HU male adolescents with a median age of 18 (interquartile range 17-20) years were enrolled. PHIV had higher incidence of any HR-HPV infection than HU adolescents {33.05 [95% confidence interval (CI): 20.82 to 52.46] vs. 15.73 [95% CI: 8.18 to 30.22] per 100 person-years, P = 0.04}. The persistence of any HR-HPV genotypes (detected at ≥2 annual visits) was not different by group (PHIV 27% vs. HU 23%, P = 0.75). Having ≥3 sex partners in past 6 months (adjusted prevalence ratio 2.39, 95% CI: 1.14 to 5.05; P = 0.02) and co-infection with other sexually transmitted infections (syphilis, chlamydia, and/or gonorrhea) were associated with persistent HR-HPV infection (adjusted prevalence ratio 6.21, 95% CI: 2.87 to 13.41; P < 0.001).

CONCLUSIONS

Thai PHIV male adolescents had a higher incidence of HR-HPV infection than those without HIV. Having multiple sex partners and co-infection with sexually transmitted infections was associated with persistent HR-HPV infection. These data demonstrate the need to prioritize PHIV male adolescents in routine and catch-up HPV vaccination programs.

Cost-effectiveness analysis of the nonavalent human papillomavirus vaccine for the prevention of cervical cancer in Singapore

BACKGROUND

The nonavalent human papillomavirus (HPV) vaccine has been shown to extend protection against oncogenic HPV types 31/33/45/52/58 (HPV-OV) not covered by the bivalent and quadrivalent HPV vaccines. Besides its clinical benefit, evidence on the economic value of the nonavalent vaccine is required to inform local vaccination strategies and funding decisions. This study evaluated the cost-effectiveness of replacing the bivalent vaccine with the nonavalent vaccine in the national school-based HPV vaccination programme in Singapore.

METHODS

An existing age-structured dynamic transmission model coupled with stochastic individual-based simulations was adapted to project the health and economic impact of vaccinating 13-year-old girls with two doses of the nonavalent or bivalent HPV vaccines in Singapore. Direct costs (in Singapore dollars, S$) were obtained from public healthcare institutions in Singapore, while health state utilities were sourced from the literature. Incremental cost-effectiveness ratios (ICERs) were estimated over a lifetime horizon, from a healthcare system perspective. Probabilistic sensitivity analysis was performed to obtain the ICERs and corresponding variations across variable uncertainty. Particularly, this study tested the scenarios of lifelong and 20-year vaccine-induced protection, assumed 96.0% and 22.3% cross-protection against HPV-OV by nonavalent and bivalent vaccines respectively, and fixed vaccine prices per dose at S$188 for nonavalent and S$61.50 for bivalent vaccines.

RESULTS

Compared with the bivalent vaccine, the use of the nonavalent vaccine was associated with an ICER of S$61,629 per quality-adjusted life year gained in the base case. The result was robust across a range of plausible input values, and to assumptions regarding the duration of vaccine protection.

CONCLUSION

Given the high ICER, the nonavalent vaccine is unlikely to represent a cost-effective option compared with the bivalent vaccine for school-based HPV vaccination of 13-year old female students in Singapore. Substantial price reductions would be required to justify its inclusion in the school-based programme in the future.

Potential health and economic impacts of dexamethasone treatment for patients with COVID-19

Dexamethasone can reduce mortality in hospitalised COVID-19 patients needing oxygen and ventilation by 18% and 36%, respectively. Here, we estimate the potential number of lives saved and life years gained if this treatment were to be rolled out in the UK and globally, as well as the cost-effectiveness of implementing this intervention. Assuming SARS-CoV-2 exposure levels of 5% to 15%, we estimate that, for the UK, approximately 12,000 (4,250 - 27,000) lives could be saved between July and December 2020. Assuming that dexamethasone has a similar effect size in settings where access to oxygen therapies is limited, this would translate into approximately 650,000 (240,000 - 1,400,000) lives saved globally over the same time period. If dexamethasone acts differently in these settings, the impact could be less than half of this value. To estimate the full potential of dexamethasone in the global fight against COVID-19, it is essential to perform clinical research in settings with limited access to oxygen and/or ventilators, for example in low- and middle-income countries.

Dexamethasone has been shown to have survival benefits for critically ill patients hospitalised with COVID-19 in the UK. Here, the authors estimated the number of lives that could be saved through a UK and global roll out of the drug and demonstrate that it is a cost-effective option.

Applying optimal control theory to complex epidemiological models to inform real-world disease management

Mathematical models provide a rational basis to inform how, where and when to control disease. Assuming an accurate spatially explicit simulation model can be fitted to spread data, it is straightforward to use it to test the performance of a range of management strategies. However, the typical complexity of simulation models and the vast set of possible controls mean that only a small subset of all possible strategies can ever be tested. An alternative approach-optimal control theory-allows the best control to be identified unambiguously. However, the complexity of the underpinning mathematics means that disease models used to identify this optimum must be very simple. We highlight two frameworks for bridging the gap between detailed epidemic simulations and optimal control theory: open-loop and model predictive control. Both these frameworks approximate a simulation model with a simpler model more amenable to mathematical analysis. Using an illustrative example model, we show the benefits of using feedback control, in which the approximation and control are updated as the epidemic progresses. Our work illustrates a new methodology to allow the insights of optimal control theory to inform practical disease management strategies, with the potential for application to diseases of humans, animals and plants. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'. This theme issue is linked with the earlier issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'.

HPV-FRAME: A consensus statement and quality framework for modelled evaluations of HPV-related cancer control

Intense research activity in HPV modelling over this decade has prompted the development of additional guidelines to those for general modelling. A specific framework is required to address different policy questions and unique complexities of HPV modelling. HPV-FRAME is an initiative to develop a consensus statement and quality-based framework for epidemiologic and economic HPV models. Its development involved an established process. Reporting standards have been structured according to seven domains reflecting distinct policy questions in HPV and cancer prevention and categorised by relevance to a population or evaluation. Population-relevant domains are: 1) HPV vaccination in pre-adolescent and young adolescent individuals; 2) HPV vaccination in older individuals; 3) targeted vaccination in men who have sex with men; 4) considerations for individuals living with HIV and 5) considerations for low- and middle-income countries. Additional considerations applicable to specific evaluations are: 6) cervical screening or integrated cervical screening and HPV vaccination approaches and 7) alternative vaccine types and alternative dosing schedules. HPV-FRAME aims to promote the development of models in accordance with an explicit framework, to better enable target audiences to understand a model's strength and weaknesses in relation to a specific policy question and ultimately improve the model's contribution to informed decision-making.

Economic burden of HPV9-related diseases: a real-world cost analysis from Italy

INTRODUCTION

The objectives of this study were to estimate the economic burden of HPV in Italy, accounting for total direct medical costs associated with nine major HPV-related diseases, and to provide a measure of the burden attributable to HPV 6, 11, 16, 18, 31, 33, 45, 52, 58 infections.

METHODS

A cost-of-illness incidence-based model was developed to estimate the incidences and costs of invasive cervical cancer, cervical dysplasia, cancer of the vulva, vagina, anus, penis, oropharyngeal, anogenital warts, and recurrent respiratory papillomatosis (RRP) in the context of the Italian National Health System (NHS). We used data from hospital discharge records (HDRs) of an Italian region and conducted a systematic literature review to estimate the lifetime cost per case, the number of incident cases, the prevalence of HPV9 types. Costs of therapeutic options not included in the diagnosis-related group (DRG) tariffs were estimated through a scenario analysis.

RESULTS

In 2018, the total annual direct costs were €542.7 million, with a range of €346.7-€782.0 million. These costs could increase considering innovative therapies for cancer treatment (range €16.2-€37.5 million). The fraction attributable to the HPV9 genotypes without innovative cancers treatment was €329.5 million, accounting for 61% of the total annual burden of HPV-related diseases in Italy. Of this amount, €135.9 million (41%) was related to men, accounting for 64% of the costs associated with non-cervical conditions.

CONCLUSIONS

The infections by HPV9 strains and the economic burden of non-cervical HPV-related diseases in men were found to be the main drivers of direct costs.

Applying optimal control theory to complex epidemiological models to inform real-world disease management

Mathematical models provide a rational basis to inform how, where and when to control disease. Assuming an accurate spatially explicit simulation model can be fitted to spread data, it is straightforward to use it to test the performance of a range of management strategies. However, the typical complexity of simulation models and the vast set of possible controls mean that only a small subset of all possible strategies can ever be tested. An alternative approach-optimal control theory-allows the best control to be identified unambiguously. However, the complexity of the underpinning mathematics means that disease models used to identify this optimum must be very simple. We highlight two frameworks for bridging the gap between detailed epidemic simulations and optimal control theory: open-loop and model predictive control. Both these frameworks approximate a simulation model with a simpler model more amenable to mathematical analysis. Using an illustrative example model, we show the benefits of using feedback control, in which the approximation and control are updated as the epidemic progresses. Our work illustrates a new methodology to allow the insights of optimal control theory to inform practical disease management strategies, with the potential for application to diseases of humans, animals and plants. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'. This theme issue is linked with the earlier issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pricing of HPV vaccines in European tender-based settings

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

Who Will Benefit From Expanding HPV Vaccination Programs to Boys?

Indications for human papillomavirus vaccination programs are expanding to boys. However, the rationale behind their inclusion is often not clear. Using a Bayesian synthesis framework and assuming equal vaccine coverage in both sexes, we assessed how the incremental number of cancer cases prevented and life-years gained from boys’ vaccination are distributed between women, heterosexual men, and men who have sex with men (MSM). Below 60% coverage, at least 50% of the gains from boys’ vaccination was attributable to cervical cancer prevention, whereas at 80% coverage, 50% of the gains was attributable to women, 15% to heterosexual men, and 35% to MSM. Above 90% coverage, 85–100% of the gains from boys’ vaccination was attributable to anal and oropharyngeal cancer prevention, mainly in MSM. Sex-neutral vaccination can be advocated on grounds of bolstering herd protection to women and directly protecting men, particularly MSM, with the clinical significance of either argument determined by the coverage.

Capturing sexual contact patterns in modelling the spread of sexually transmitted infections: Evidence using Natsal-3

BACKGROUND

Understanding the spread of sexually transmitted infections (STIs) in a population is of great importance to the planning and delivery of health services globally. The worldwide rise of HIV since the 1980's, and the recent increase in common STIs (including HPV and Chlamydia) in many countries, means that there is an urgent need to understand transmission dynamics in order to better predict the spread of such infections in the population. Unlike many other infections which can be captured by assumptions of random mixing, STI transmission is intimately linked to the number and pattern of sexual contacts. In fact, it is the huge variation in the number of new sexual partners that gives rise to the extremes of risk within populations which need to be captured in predictive models of STI transmission. Such models are vital in providing the necessary scientific evidence to determine whether a range of controls (from education to screening to vaccination) are cost-effective.

METHOD AND RESULTS

We use probability sample survey data from Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3) to determine robust distributions for the rate of new partnerships that involve condomless sex and can therefore facilitate the spread of STIs. Different distributions are defined depending on four individual-level characteristics: age, sex, sexual orientation, and previous sexual experience. As individual behaviour patterns can change (e.g. by remaining in a monogamous relationship for a long period) we allow risk-percentiles to be randomly redrawn, to capture longer term behaviour as measured by Natsal-3. We demonstrate how this model formulation interacts with the transmission of infection by constructing an individual-based SIS-P (Susceptible-Infected-Susceptible-Protected) transmission model for the spread of a generic STI, and observing overall population demographics when varying the transmission probability within a partnership, recovery rate and the level of population protection (e.g. from vaccination where applicable).

Present challenges in cervical cancer prevention: Answers from cost-effectiveness analyses

Simulation models are commonly used to address important health policy issues that cannot be explored through experimental studies. These models are especially useful to determine a set of strategies that result in a good value for money (cost-effectiveness). Several mathematical models simulating the natural history of HPV and related diseases, especially cervical cancer, have been developed to calculate a relative effectiveness and cost-effectiveness of HPV vaccination and cervical cancer screening interventions. Virtually all cost-effectiveness analyses identify HPV vaccination programmes for preadolescent girls to be cost-effective, even for relatively low vaccination coverage rates. Routine vaccination of preadolescent girls is the primary target population for HPV vaccination as it shows to provide the greatest health impact. Cost-effectiveness analyses assessing other vaccine target groups are less conclusive. Adding additional age-cohorts would accelerate health benefits in some years, although cost-effectiveness becomes less favourable as age at vaccination increases. Including men in HPV vaccination programmes may be a less efficient strategy if done at the expense of female vaccination coverage for reducing the burden of HPV in the population. However, as the HPV vaccine price decreases, the cost-effectiveness of universal vaccination improves, becoming equally as efficient as female-only vaccination. Vaccine price is a decisive factor in the cost-effectiveness analyses. The lower the price, the greater the likelihood that vaccination groups other than the primary target would be considered cost-effective.

Should human papillomavirus vaccination target women over age 26, heterosexual men and men who have sex with men? A targeted literature review of cost-effectiveness

BACKGROUND

Human papillomavirus (HPV) vaccination for young women up to age 26 is highly cost-effective and has been implemented in 65 countries globally. We investigate the cost-effectiveness for HPV vaccination program in older women (age > 26 years), heterosexual men and men who have sex with men (MSM).

METHOD

A targeted literature review was conducted on PubMed for publications between January 2000 and January 2017 according to the PRISMA guidelines. We included English-language articles that reported the incremental cost-effectiveness ratio (ICER) of HPV vaccination programs for women over age 26, heterosexual men, and MSM and identified the underlying factors for its cost-effectiveness.

RESULTS

We included 36 relevant articles (six, 26 and four in older women, heterosexual men and MSM, respectively) from 17 countries (12 high-income (HICs) and five low- and middle-income (LMICs) countries). Most (4/6) studies in women over age 26 did not show cost-effectiveness ($65,000-192,000/QALY gained). Two showed cost-effectiveness, but only when the vaccine cost was largely subsidised and protection to non-naïve women was also considered. Sixteen of 26 studies in heterosexual men were cost-effective (ICER = $19,600-52,800/QALY gained in HICs; $49-5,860/QALY gained in LMICs). Nonavalent vaccines, a low vaccine price, fewer required doses, and a long vaccine protection period were key drivers for cost-effectiveness. In contrast, all four studies on MSM consistently reported cost-effectiveness (ICER = $15,000-$43,000/QALY gained), particularly in MSM age < 40 years and those who were HIV-positive. Countries' vaccination coverage did not significantly correlate with its per-capita Gross National Income.

CONCLUSION

Targeted HPV vaccination for MSM should be next priority in HPV prevention after having established a solid girls vaccination programme. Vaccination for heterosexual men should be considered when 2-dose 4vHPV/9vHPV vaccines become available with a reduced price, whereas targeted vaccination for women over age 26 is unlikely to be cost-effective.

A dynamic Bayesian Markov model for health economic evaluations of interventions in infectious disease

BACKGROUND

Health economic evaluations of interventions in infectious disease are commonly based on the predictions of ordinary differential equation (ODE) systems or Markov models (MMs). Standard MMs are static, whereas ODE systems are usually dynamic and account for herd immunity which is crucial to prevent overestimation of infection prevalence. Complex ODE systems including distributions on model parameters are computationally intensive. Thus, mainly ODE-based models including fixed parameter values are presented in the literature. These do not account for parameter uncertainty. As a consequence, probabilistic sensitivity analysis (PSA), a crucial component of health economic evaluations, cannot be conducted straightforwardly.

METHODS

We present a dynamic MM under a Bayesian framework. We extend a static MM by incorporating the force of infection into the state allocation algorithm. The corresponding output is based on dynamic changes in prevalence and thus accounts for herd immunity. In contrast to deterministic ODE-based models, PSA can be conducted straightforwardly. We introduce a case study of a fictional sexually transmitted infection and compare our dynamic Bayesian MM to a deterministic and a Bayesian ODE system. The models are calibrated to simulated time series data.

RESULTS

By means of the case study, we show that our methodology produces outcome which is comparable to the "gold standard" of the Bayesian ODE system.

CONCLUSIONS

In contrast to ODE systems in the literature, the dynamic MM includes distributions on all model parameters at manageable computational effort (including calibration). The run time of the Bayesian ODE system is 15 times longer.

Concurrency of partnerships, consistency with data, and control of sexually transmitted infections

Sexually transmitted infections (STIs) are a globally increasing public health problem. Mathematical models, carefully matched to available epidemiological and behavioural data, have an important role to play in predicting the action of control measures. Here, we explore the effect of concurrent sexual partnerships on the control of a generic STI with susceptible-infected-susceptible dynamics. Concurrency refers to being in more than one sexual partnership at the same time, and is difficult to measure accurately. We assess the impact of concurrency through the development of three nested pair-formation models: one where infection can only be transmitted via stable sexual partnerships, one where infection can also be transmitted via casual partnerships between single individuals, and one where those individuals in stable partnerships can also acquire infection from casual partnerships. For each model, we include the action of vaccination before sexual debut to inform about the ability to control. As expected, for a fixed transmission rate, concurrency increases both the endemic prevalence of infection and critical level of vaccination required to eliminate the disease significantly. However, when the transmission rate is scaled to maintain a fixed endemic prevalence across models, concurrency has a far smaller impact upon the critical level of vaccination required. Further, when we also constrain the models to have a fixed number of new partnerships over time (both long-term and casual), then increasing concurrency can slightly decrease the critical level of vaccination. These results highlight that accurate measures and models of concurrency may not always be needed for reliable forecasts when models are closely matched to prevalence data. We find that, while increases in concurrency within a population are likely to generate public-health problems, the inclusion of concurrency may be unnecessary when constructing models to determine the efficacy of the control of STIs by vaccination.

Systematic review of cost-effectiveness studies of human papillomavirus (HPV) vaccination: 9-Valent vaccine, gender-neutral and multiple age cohort vaccination

BACKGROUND

The success of human papillomavirus (HPV) national immunization program depends on effective strategies in optimizing the uptake of HPV vaccine. Given the increasing number of economic evaluations, this review was conducted to update the economic evidence on HPV vaccination, by focusing on: (i) 9-valent vaccine compared to bi- or quadrivalent vaccine; (ii) gender-neutral vaccination compared to female only vaccination; and (iii) multiple age cohort immunization compared to single age cohort immunization.

METHODS

Searches were performed until June 2016 using 4 databases: PubMed; Embase; Cochrane Library; and LILACS. The combined WHO, Drummond and CHEERS checklist were used to evaluate the quality of included studies.

RESULTS

Thirty-four studies were included in the review and most of them were conducted in high-income countries. The inclusion of adolescent boys in vaccination program was found to be cost-effective if vaccine price and coverage was low. When coverage for female was above 75%, gender-neutral vaccination was less cost-effective than when targeting only girls aged 9-18 years. Current evidence does not show conclusive proof of greater cost-effectiveness of 9-valent vaccine compared to the older HPV vaccines as the price for 9-valent vaccine was still uncertain. Multicohort immunization strategy was cost-effective in the age range 9-14 years but the upper age limit at which vaccination was no longer cost-effective needs to be further investigated. Key influential parameters identified were duration of vaccine protection, vaccine price, coverage, and discounting rates.

CONCLUSIONS

These findings are expected to support policy-makers in making recommendations for HPV immunization programs on either switching to the 9-valent vaccine or inclusion of adolescent boys' vaccination or extending the age of vaccination.

Age of Acquiring Causal Human Papillomavirus (HPV) Infections: Leveraging Simulation Models to Explore the Natural History of HPV-induced Cervical Cancer

Background

Although new human papillomavirus (HPV) infections can occur at all ages, the age at which women acquire their "causal" HPV infection that develops into cervical cancer is poorly understood and practically unobservable. We aimed to estimate the age distribution at which individuals acquired their causal HPV infection in the absence of HPV vaccination or screening to help guide the optimal use of both.

Methods

Using an empirically calibrated mathematical model that simulates the natural history of cervical cancer, we estimated the cumulative number of causal HPV infections by age, stratified by HPV genotype (HPV16 vs. other HPV genotypes), and the direct age-specific reduction in cancer incidence for alternative vaccination initiation scenarios (i.e., age 9-45 years).

Results

Our model projected that among all cervical cancers, 50% and 75% of women acquired their causal HPV infection by ages 20.6 (range: 20.1-21.1) and 30.6 (range: 29.6-31.6) years, respectively. HPV16 infections were acquired at an earlier age. Assuming 95% efficacy against HPV16 and HPV18 infections, the direct reduction in lifetime risk of cervical cancer varied from 55% (53-56%) among women vaccinated at age 9 years to 6% (range: 6-7%) among women vaccinated at age 45 years. Similar patterns were observed for the second-generation vaccine.

Conclusions

Although new HPV infections and precancers can occur throughout a woman's lifetime, only a small proportion are acquired in mid-adult women and are vaccine-preventable. Our simulations highlight the potential limitations of using surrogate endpoints for vaccine efficacy studies of mid-adult women to guide policy decisions for implementation.

Impact and Cost-effectiveness of Selective Human Papillomavirus Vaccination of Men Who Have Sex With Men

Background.

Men who have sex with men (MSM) have a high lifetime risk of anogenital warts and cancers related to infection with human papillomavirus (HPV). They also benefit less from herd protection than heterosexual males in settings with female-only HPV vaccination.

Methods.

We evaluated the potential health impact and cost-effectiveness of offering vaccination to MSM who visit genitourinary medicine (GUM) clinics. We used a mathematical model of HPV 6/11/16/18 sexual transmission within an MSM population in England, parameterized with sexual behaviour, GUM attendance, HPV prevalence, HIV prevalence, warts, and cancer incidence data. Interventions considered were offering HPV vaccination to either HIV-positive MSM or MSM regardless of HIV status, for age bands 16–25, 16–30, 16–35, and 16–40 years.

Results.

Substantial declines in anogenital warts and male HPV-related cancer incidence are projected to occur following an offer of vaccination to MSM. MSM not attending GUM clinics will partially benefit from herd protection. Offering vaccination to HIV-positive MSM up to age 40 is likely to be cost-effective if vaccine procurement and administration costs are below £96.50 a dose. At £48 a dose, offering vaccination to all MSM up to age 40 is likely to be cost-effective.

Conclusions.

Quadrivalent HPV vaccination of MSM via GUM clinics is likely to be an effective and cost-effective way of reducing the burden of HPV-related disease in MSM.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Health and Economic Impact of a Tender-Based, Sex-Neutral Human Papillomavirus 16/18 Vaccination Program in the Netherlands

Background

Uptake of human papillomavirus (HPV) vaccine among girls in the Dutch immunization program has plateaued at around 60%. Vaccinating boys may be an appealing complementary strategy for the prevention of HPV-related diseases, especially since tender negotiations and reduced dosing schemes have driven down the cost of vaccination.

Methods

We expanded a previously published Bayesian synthesis framework to account for all vaccine type-related cancers and herd immunity effects from vaccinating girls and boys. We evaluated the efficiency of vaccinating boys relative to increasing vaccine uptake among girls and assessed the cost-effectiveness of a sex-neutral program.

Results

Vaccinating 40% of boys along with 60% of girls yielded the same gain in life-years (LYs) as increasing the uptake in girls from 60% to 80%. The incremental cost-effectiveness ratio (ICER) of vaccinating boys was €9134/LY (95% credible interval [CrI], €7323/LY-€11231/LY) under 3% discounting. The ceiling vaccination costs at which the ICER remained below the per capita gross domestic product threshold was €240 (95% CrI, €200-€280) per vaccinated boy. If girls' uptake increased to 90%, the ceiling costs decreased to €70 (95% CrI, €40-€100) per vaccinated boy.

Conclusions

Vaccinating boys along with girls is only modestly less efficient than increasing uptake among girls and highly likely to be cost-effective under current vaccine costs and uptake in the Netherlands.

Cost-effectiveness analysis of the nine-valent HPV vaccine in Italy

Background

In Italy HPV vaccination with the quadrivalent vaccine (Gardasil^®) is offered actively and free of charge to girls aged 12 since 2007. A nine-valent vaccine (Gardasil 9^®) received the European market authorization in 2015 to protect, with only 2 doses, against around 90% of all HPV positive cancers, over 80% of high-grade precancerous lesions and 90% of genital warts caused by HPV types 6/11.

Methods

A dynamic transmission model simulating the natural history of HPV-infections was calibrated to the Italian setting and used to estimate costs and QALYs associated with vaccination strategies. The analyses compared two strategies with the nine-valent vaccine (cervical cancer screening and vaccination in girls only or vaccination in boys and girls) to four alternative strategies (cervical cancer screening and vaccination with quadrialent vaccine in girls only, in both boys and girls, with bivalent vaccine in girls and screening strategy only). The National Health Service perspective was considered.

Conclusion

The switch to the nine-valent vaccine in Italy can further reduce the burden associated to cervical cancer and HPV-related diseases and is highly cost-effective.

Results

Compared to the current vaccination program with quadrivalent vaccine, the nine-valent vaccine in a programme including girls and boys shows further reductions of 17% in the incidence of cervical cancer, 35 and 14% in anal cancer for males and females, as well as over a million cases of genital warts avoided after 100 years. The new technology is associated with an ICER of 10,463€ per QALY gained in universal vaccination, decreasing to 4483€ when considering the vaccine switch for girls-only.

Electronic supplementary material

The online version of this article (doi:10.1186/s12962-017-0073-8) contains supplementary material, which is available to authorized users.

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.

Surveillance of Vaccination Coverage among Adult Populations - United States, 2015

PROBLEM/CONDITION

Overall, the prevalence of illness attributable to vaccine-preventable diseases is greater among adults than among children. Adults are recommended to receive vaccinations based on their age, underlying medical conditions, lifestyle, prior vaccinations, and other considerations. Updated vaccination recommendations from CDC are published annually in the U.S. Adult Immunization Schedule. Despite longstanding recommendations for use of many vaccines, vaccination coverage among U.S. adults is low.

PERIOD COVERED

August 2014-June 2015 (for influenza vaccination) and January-December 2015 (for pneumococcal, tetanus and diphtheria [Td] and tetanus and diphtheria with acellular pertussis [Tdap], hepatitis A, hepatitis B, herpes zoster, and human papillomavirus [HPV] vaccination).

DESCRIPTION OF SYSTEM

The National Health Interview Survey (NHIS) is a continuous, cross-sectional national household survey of the noninstitutionalized U.S. civilian population. In-person interviews are conducted throughout the year in a probability sample of households, and NHIS data are compiled and released annually. The survey objective is to monitor the health of the U.S. population and provide estimates of health indicators, health care use and access, and health-related behaviors.

RESULTS

Compared with data from the 2014 NHIS, increases in vaccination coverage occurred for influenza vaccine among adults aged ≥19 years (a 1.6 percentage point increase compared with the 2013-14 season to 44.8%), pneumococcal vaccine among adults aged 19-64 years at increased risk for pneumococcal disease (a 2.8 percentage point increase to 23.0%), Tdap vaccine among adults aged ≥19 years and adults aged 19-64 years (a 3.1 percentage point and 3.3 percentage point increase to 23.1% and to 24.7%, respectively), herpes zoster vaccine among adults aged ≥60 years and adults aged ≥65 years (a 2.7 percentage point and 3.2 percentage point increase to 30.6% and to 34.2%, respectively), and hepatitis B vaccine among health care personnel (HCP) aged ≥19 years (a 4.1 percentage point increase to 64.7%). Herpes zoster vaccination coverage in 2015 met the Healthy People 2020 target of 30%. Aside from these modest improvements, vaccination coverage among adults in 2015 was similar to estimates from 2014. Racial/ethnic differences in coverage persisted for all seven vaccines, with higher coverage generally for whites compared with most other groups. Adults without health insurance reported receipt of influenza vaccine (all age groups), pneumococcal vaccine (adults aged 19-64 years at increased risk), Td vaccine (adults aged ≥19 years, 19-64 years, and 50-64 years), Tdap vaccine (adults aged ≥19 years and 19-64 years), hepatitis A vaccine (adults aged ≥19 years overall and among travelers), hepatitis B vaccine (adults aged ≥19 years, 19-49 years, and among travelers), herpes zoster vaccine (adults aged ≥60 years), and HPV vaccine (males and females aged 19-26 years) less often than those with health insurance. Adults who reported having a usual place for health care generally reported receipt of recommended vaccinations more often than those who did not have such a place, regardless of whether they had health insurance. Vaccination coverage was higher among adults reporting one or more physician contacts in the past year compared with those who had not visited a physician in the past year, regardless of whether they had health insurance. Even among adults who had health insurance and ≥10 physician contacts within the past year, depending on the vaccine, 18.2%-85.6% reported not having received vaccinations that were recommended either for all persons or for those with specific indications. Overall, vaccination coverage among U.S.-born adults was higher than that among foreign-born adults, with few exceptions (influenza vaccination [adults aged 19-49 years and 50-64 years], hepatitis A vaccination [adults aged ≥19 years], and hepatitis B vaccination [adults aged ≥19 years with diabetes or chronic liver conditions]).

INTERPRETATION

Coverage for all vaccines for adults remained low but modest gains occurred in vaccination coverage for influenza (adults aged ≥19 years), pneumococcal (adults aged 19-64 years with increased risk), Tdap (adults aged ≥19 years and adults aged 19-64 years), herpes zoster (adults aged ≥60 years and ≥65 years), and hepatitis B (HCP aged ≥19 years); coverage for other vaccines and groups with vaccination indications did not improve. The 30% Healthy People 2020 target for herpes zoster vaccination was met. Racial/ethnic disparities persisted for routinely recommended adult vaccines. Missed opportunities to vaccinate remained. Although having health insurance coverage and a usual place for health care were associated with higher vaccination coverage, these factors alone were not associated with optimal adult vaccination coverage. HPV vaccination coverage for males and females has increased since CDC recommended vaccination to prevent cancers caused by HPV, but many adolescents and young adults remained unvaccinated.

PUBLIC HEALTH ACTIONS

Assessing factors associated with low coverage rates and disparities in vaccination is important for implementing strategies to improve vaccination coverage. Evidence-based practices that have been demonstrated to improve vaccination coverage should be used. These practices include assessment of patients' vaccination indications by health care providers and routine recommendation and offer of needed vaccines to adults, implementation of reminder-recall systems, use of standing-order programs for vaccination, and assessment of practice-level vaccination rates with feedback to staff members. For vaccination coverage to be improved among those who reported lower coverage rates of recommended adult vaccines, efforts also are needed to identify adults who do not have a regular provider or insurance and who report fewer health care visits.

Prevalence and Determinants of Oral Human Papillomavirus Infection in 500 Young Adults from Italy

Although the prevalence of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) is increasing in developed countries and becoming a relevant health issue, the natural history of oral HPV infection is still unclear. Estimating the infection's prevalence in specific populations and identifying risk factors can widen our understanding of its natural history and help to delineate appropriate prevention strategies. This study sought to (i) determine oral HPV prevalence and genotype distribution in a large series of young Italian adults, (ii) validate an oral rinse sampling/storage protocol, and (iii) pinpoint factors associated with oral HPV infection. Five hundred students, nurses, and technicians (19-35 years-old) studying and working at/for the University of Padua were recruited. Each participant was provided with an oral rinse sampling kit and instructions for use. They were also asked to complete an anonymous questionnaire concerning their demographic characteristics and behaviors. The questionnaires and oral rinse containers were labeled with the same identification code number. The oral rinse samples were tested using a bead-based multiplex BSGP5+/6+-MPG genotyping assay which amplifies the L1 region of 51 mucosal HPV types. The prevalence of oral HPV infection was 4.0% (95% confidence interval (CI), 2.5%-6.1%); those of 14 high-risk HPV types and of HPV-type 16 (HPV16) infection were 2.2% (95% CI, 1.1%-3.9%) and 1.6% (95% CI, 0.6%-3.1%), respectively. HPV16 was the most frequent genotype (40.0% of oral HPV infections). No association was found between oral infection and the co-variables studied (gender, tobacco, alcohol and illegal drug use, number of sex and oral sex partners, HPV vaccination status, history of HPV and sexually transmitted infections, abnormal pap smears, recurrent tonsillitis and tonsillectomy). The oral rinse sampling protocol outlined here proved to be simple, efficient and well tolerated, and the prevalence rate can be considered reliable and thus useful to guide future research. Determinants of oral HPV infection are still unclear and further studies are certainly warranted.

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.

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

INTRODUCTION

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

Human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine for the prevention of cervical cancer and HPV-related diseases

Vaccines are available against human papillomavirus (HPV), the causal agent of cervical and other cancers. Efficacy data from the HPV-16/18 AS04-adjuvanted vaccine clinical trial program were reviewed. Six randomized, controlled phase II/III trials evaluating cervical endpoints enrolled women from diverse populations and geographical locations. The program analyzed extensively the cohorts most relevant from a public health perspective: the total vaccinated cohort (TVC), approximating a general population including those with existing or previous HPV infection, and TVC-naïve, approximating a population of young women before sexual debut. Results show that the vaccine reduces HPV-16/18 infection and associated cervical endpoints in women regardless of age, location, or sexual experience. It provides cross-protection against some non-vaccine oncogenic HPV types and types causing genital warts, and may be effective against vulvar, oral, and anal HPV infection. Early epidemiology data following its introduction suggest a decline in the prevalence of vaccine and some non-vaccine HPV types.

The economic evaluation of human papillomavirus vaccination strategies against cervical cancer in women in Lao PDR: a mathematical modelling approach

BACKGROUND

Cervical cancer, a preventable disease, is the third leading cause of cancer morbidity and mortality in the Lao People's Democratic Republic (Lao PDR). Since many cervical cancers are linked to human papilloma virus (HPV) infection, vaccination against this virus may lead to a reduction in these types of cancer. The study described here is the first to compare the cost-effectiveness of different HPV vaccination options in Lao PDR.

METHODS

A dynamic compartment model was created. The model included routine screening activities already in place, as well as theoretical interventions that included a 10-year old girl-only vaccination programme combined with/without a 10-year old boy vaccination programme and/or a catch-up component. The simulation was run over 100 years. In base case analyses, we assumed 70 % vaccination coverage with lifelong protection and 100 % efficacy against HPV types 16/18. The outcomes of interest were the incremental cost per Disability-Adjusted Life Year (DALY) averted.

RESULTS

In base case analyses, according to the WHO definition of cost-effectiveness thresholds, vaccinating 10-year-old girls was very cost-effective. Adding a catch-up vaccination element for females aged 11-25 years was also very cost-effective, costing 1559 international dollars (I$) per DALY averted. Increasing the age limit of the catch-up vaccination component to 75 years old showed that this remained a cost-effective option (I$ 5840 per DALY averted). Adding a vaccination programme for 10-year-old boys was not found to be cost-effective unless a short time simulation (30 years or less) was considered, along with a catch-up vaccination component for both males and females.

CONCLUSIONS

Adding a catch-up female vaccination component is more attractive than adding a 10-year-old boy vaccination component.

Extending the Human Papillomavirus Vaccination Programme to Include Males in High-Income Countries: A Systematic Review of the Cost-Effectiveness Studies

BACKGROUND AND OBJECTIVES

Giving the human papillomavirus (HPV) vaccination to females has been shown to be cost-effective in most countries. The epidemiological evidence and economic burden of HPV-related diseases have gradually been shown to be gender neutral. Randomized clinical trials report high efficacy, immunogenicity and safety of the HPV vaccine in males aged 16-26 years. Some pioneering countries extended their HPV vaccination programme to include males, regardless of the cost-effectiveness analysis results. Nevertheless, decision makers need evidence provided by modelling and economic studies to justify the funding of mass vaccination. This systematic review aims to assess the cost-effectiveness of extending the HPV vaccination programme to include males living in high-income countries.

METHODS

A systematic review of the cost-effectiveness analyses of HPV vaccination in males was performed. Data were extracted and analysed using a checklist adapted from the Consolidated Health Economic Evaluation Reporting Standards Statement.

RESULTS

Seventeen studies and 12 underlying mathematical models were identified. Model filiation showed evolution in time from aggregate models (static and dynamic) to individual-based models. When considering the health outcomes HPV vaccines are licensed for, regardless of modelling approaches and assumptions, extending vaccinations to males is rarely found to be cost-effective in heterosexual populations. Cost-effectiveness ratios become more attractive when all HPV-related diseases are considered and when vaccine coverage in females is below 40%.

CONCLUSION

Targeted vaccination of men who have sex with men (MSM) seems to be the best cost-effectiveness option. The feasibility of this strategy is still an open question, since early identification of this specific population remains difficult.

Gender-neutrality, herd effect and resilient immune response for sustainable impact of HPV vaccination

PURPOSE OF REVIEW

This review summarize the impact of various strategies of human papillomavirus (HPV) vaccination, such as vaccinating only girls or both girls and boys.

RECENT FINDINGS

Slow and inefficient implementation of HPV vaccination programmes has delayed the impact of the first human cancer vaccine. Vaccinating only girls, with a rather low coverage, has led to a limited herd effect and, thus, not full use of the HPV vaccine potential.

SUMMARY

Gender-neutral vaccination based on comparative effectiveness research will hopefully soon tackle the whole spectrum of HPV cancers in both sexes. The remaining challenges are how to ensure resilience of HPV vaccine-induced immunity and herd effect to guarantee population-level impact of HPV vaccination, and how to guard against HPV type replacement.

Genital Chlamydia trachomatis: understanding the roles of innate and adaptive immunity in vaccine research

Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract, Chlamydia trachomatis infects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.

Economic evaluation of pediatric influenza immunization program compared with other pediatric immunization programs: A systematic review

This study compared the economic value of pediatric immunisation programmes for influenza to those for rotavirus (RV), meningococcal disease (MD), pneumococcal disease (PD), human papillomavirus (HPV), hepatitis B (Hep B), and varicella reported in recent (2000 onwards) cost-effectiveness (CE) studies identified in a systematic review of PubMed, health technology, and vaccination databases. The systematic review yielded 51 economic evaluation studies of pediatric immunisation - 10 (20%) for influenza and 41 (80%) for the other selected diseases. The quality of the eligible articles was assessed using Drummond's checklist. Although inherent challenges and limitations exist when comparing economic evaluations of immunisation programmes, an overall comparison of the included studies demonstrated cost-effectiveness/cost saving for influenza from a European-Union-Five (EU5) and United States (US) perspective; point estimates for cost/quality-adjusted life-years (QALY) from dominance (cost-saving with more effect) to ≤45,444 were reported. The economic value of influenza programmes was comparable to the other vaccines of interest, with cost/QALY in general considerably lower than RV, Hep B, MD and PD. Independent of the perspective and type of analysis, the economic impact of a pediatric influenza immunisation program was influenced by vaccine efficacy, immunisation coverage, costs, and most significantly by herd immunity. This review suggests that pediatric influenza immunisation may offer a cost effective strategy when compared with HPV and varicella and possibly more value compared with other childhood vaccines (RV, Hep B, MD and PD).

HPV vaccines: how many doses are needed for protection?

HPV virus-like particle vaccines are highly immunogenic, well tolerated and are in the national immunization programs in more than 62 countries. Genital HPV is a sexually transmitted infection with first infection occurring just after the onset of sexual activity. The routine cohort for immunization in almost all countries are adolescent girls 9–15 years of age with or without catch-up for older adolescents and young women. In countries with vaccine coverage exceeding 50%, reductions in vaccine type HPV geno-prevalence and disease are being shown. The mechanism of protection is assumed to be via neutralizing antibody. Antibody concentration in adolescents less than 14 years of age after two doses of vaccine at 0 and 6 months are noninferior to women after three doses and in whom efficacy was demonstrated in randomized control trials. The original three-dose schedules have already been reduced in many countries, for those 14 years of age and under, to two doses at least 6 months apart for the licensed vaccines Cervarix® and GARDASIL®. There is preliminary evidence that one dose of vaccine is as effective as two or three doses at preventing persistent HPV infection in the cervix in young women and a one-dose schedule may be possible if supported by evidence from randomized controlled trials.

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.

Effect of vaccination age on cost-effectiveness of human papillomavirus vaccination against cervical cancer in China

Background

The cost-effectiveness of human papillomavirus (HPV) vaccination in women pre-sexual debut has been demonstrated in many countries. This study aimed to estimate the cost-effectiveness of a 3-dose bivalent HPV vaccination at ages 12 to 55 year in both rural and urban settings in China.

Methods

The Markov cohort model simulated the natural history of HPV infection and included the effect of screening and HPV vaccination over the lifetime of a 100,000 female cohort. Transition probabilities and utilities were obtained from published literature. Cost data were estimated by Delphi panel using healthcare payers’ perspective. Vaccine cost was assumed Hong Kong listed price. Vaccine efficacy (VE) was based on the PATRICIA trial data assuming VE irrespective of HPV type at all ages on incident HPV. Costs and outcomes were discounted at 3 %. Cervical cancer cases and incremental cost-effectiveness ratio (ICER) for vaccination and screening compared with screening alone were estimated for each vaccination age. Reduced VE in women post-sexual debut were investigated in scenario analyses.

Results

With 70 % vaccination coverage, a reduction of cancer cases varying from 585 to 33 in rural and 691 to 32 in urban were estimated at ages 12 to 55, respectively. The discounted ICERs of vaccination at any age under 23 years in rural and any age under 25 years in urban were lower than the current threshold. Scenario analyses with lower VE post-sexual debut confirmed the results with age 20 in rural and 21 in urban had consistent lower ICERs. The more ‘catch-up’ cohorts vaccinated at the start of a program, the more cancer lesions are avoided in the long-term.

Conclusions

Vaccination at any age under 23 years old in rural and any age under 25 years old in urban were cost-effective. Catch-up to the age of 25 years in rural and urban could still be cost-effective.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2207-3) contains supplementary material, which is available to authorized users.

HPV vaccination in boys and men

Human papillomaviruses are DNA viruses that infect skin or mucosal cells. In the genital tract HPV (especially types 6 and 11) cause genital warts, the commonest viral sexually transmitted disease. At least 13 of the more than 100 known HPV genotypes are oncogenic "high-risk" genotypes. The 2 most common of these (genotypes 16 and 18) cause approximately 70% of all cervical cancers. Oncogenic HPVs particularly HPV 16 are associated with other anogenital cancers, anus, vagina, vulva and penis, and cancers of the head and neck and current estimates are that 5.2% of all cancers are HPV associated. In industrialised countries cervical cancer is controlled by secondary intervention other HPV associated malignancies are increasing in incidence and the burden of HPV associated disease in men is now comparable to that in women in economically developed countries. Randomized control trials with the quadrivalent HPV VLP vaccine demonstrate robust antibody responses and high efficacy against genital warts anal precancers in men. Few countries have recommended male vaccination on the basis that this is not cost effective. However gender-neutral vaccination has been recommended in the USA, Canada, Austria, and Australia. Careful cost effective modeling has preceded these decisions showing that when the burden of disease in men is included in the models then, depending upon coverage, vaccine price, and other factors male vaccination can become cost effective.