Evaluating human papillomavirus vaccination programs

Human papillomavirus vaccination uptake and determinant factors among adolescent schoolgirls in sub-Saharan Africa: A systematic review and meta-analysis

Despite the ongoing global vaccination campaign aimed at preventing human papillomavirus (HPV) related health issues, the uptake of the HPV vaccine remains unacceptably low in developing regions, particularly in sub-Saharan Africa (SSA). Therefore, this systematic review and meta-analysis aimed at determining the pooled prevalence and associated factors of HPV vaccine uptake among adolescent school girls in SSA. Electronic bio-medical databases were explored. Pooled prevalence, publication bias, meta-regression, sub-group, and sensitivity analysis were performed. The estimated pooled prevalence of HPV vaccine uptake was 28.53% [95% CI: (5.25, 51.81)]. Having good knowledge and a positive attitude was significantly associated with HPV vaccine uptake in SSA. Subgroup analysis revealed the highest uptake was 62.52% from Kenya and the lowest was 3.77% in Nigeria. The HPV vaccine uptake is low. It underscores the need for community education, school-based immunization, and education programs that promote the uptake of the vaccine to increase coverage.

Effective vaccination strategies for human papillomavirus (HPV) infection and cervical cancer based on the mathematical model with a stochastic process

Human papillomavirus (HPV) infection poses a significant risk to women's health by causing cervical cancer. In addition to HPV, cervical cancer incidence rates can be influenced by various factors, including human immunodeficiency virus and herpes, as well as screening policy. In this study, a mathematical model with stochastic processes was developed to analyze HPV transmission between genders and its subsequent impact on cervical cancer incidence. The model simulations suggest that both-gender vaccination is far more effective than female-only vaccination in preventing an increase in cervical cancer incidence. With increasing stochasticity, the difference between the number of patients in the vaccinated group and the number in the nonvaccinated group diminishes. To distinguish the patient population distribution of the vaccinated from the nonvaccinated, we calculated effect size (Cohen's distance) in addition to Student's t-test. The model analysis suggests a threshold vaccination rate for both genders for a clear reduction of cancer incidence when significant stochastic factors are present.

Lip, oral and oropharyngeal cancer incidence among Aboriginal and Torres Strait Islander Peoples: First report from Australian population-based cancer registry, 1999-2018

BACKGROUND

The Australian Burden of Disease Study has shown that cancer is the single most important entity responsible for the greatest cause of health burden in Australia. Unfortunately, Aboriginal and Torres Strait Islander peoples experience a greater burden of this disease, with cancer of the lung, breast, bowel and prostrate being the most common. Lip, oral cavity and pharyngeal cancer incidence is rapidly rising globally and is now the sixth most common cancer in Australia. This paper aims to summarize, for the first time, the incidence and prevalence trends of lip, oral cavity and pharyngeal cancers in Aboriginal and Torres Strait Islander Australians.

METHODS

Data were obtained from the Australian Cancer Database (ACD), which is compiled at the Australian Institute of Health and Welfare (AIHW) from 1999 to 2018 to estimate the incidence and prevalence of certain head and neck cancers (ICD-10 codes C00-C10, C14). The other variables requested were age groups and sex.

RESULTS

Results were stratified by ICD-10 code, sex and age group at diagnosis and time period (i.e. grouped years of diagnosis). The total incidence of lip, oral cavity and pharyngeal cancers increased by 1.3 times from 1999 to 2008 (107/100 000) to 2009-2018 (135/100 000). The overall 5-year prevalence of lip, oral cavity and pharyngeal cancers was 0.17% (0.24% for men and 0.09% for women).

CONCLUSIONS

The significantly increased incidence of lip, oral cavity and pharyngeal cancers in Aboriginal and Torres Strait Islander peoples in Australia is concerning and should be explored. A targeted, comprehensive and culturally safe model of care for Aboriginal and Torres Strait Islander peoples with lip, oral cavity and pharyngeal cancers is imperative.

Community myths and misconceptions about sexual health in Tanzania: Stakeholders' views from a qualitative study in Dar es Salaam Tanzania

INTRODUCTION

Sexual and reproductive health problems are one of the top five risk factors for disability in the developing world. The rates of sexual health problems in most African countries are overwhelming, which is why HIV and other STIs are still such a challenge in sub-Saharan Africa. Talking about sex in most African countries is a taboo, leading to common myths and misconceptions that ultimately impact community sexual health.

METHODS

In this study, we conducted 11 key stakeholder individual interviews with community, religious, political, and health leaders (sexual health stakeholders) in Tanzania. Qualitative content analysis was used to analyze all the materials.

RESULTS

Two main categories merged from the analysis. The first category, "Ambiguities about sexual health" focused on societal and political misconceptions and identified ten myths or misconceptions common in Tanzania. Stakeholders highlighted the confusion that happens when different information about sexual health is presented from two different sources (e.g., community leaders/peers and political leaders), which leaves the community and community leaders unsure which one is reliable. The second category, "Practical dilemmas in serving clients", addressed a range of professional and religious dilemmas in addressing sexual health concerns. This included the inability of religious leaders and health care providers to provide appropriate sexual health care because of internal or external influences.

CONCLUSION

Myths and misconceptions surrounding sexual health can prevent communities from adequately addressing sexual health concerns, and make it more difficult for healthcare providers to comfortably provide sexual health care to patients and communities. Stakeholders affirmed a need to develop a sexual health curriculum for medical, nursing and midwifery students because of the lack of education in this area. Such a curriculum needs to address nine common myths which were identified through the interviews.

Exploring Vaccination Sentiments: A Population-Centric Examination

Vaccine hesitancy has, for a considerable time, been a significant risk to global health. As an integral part of disease prevention, vaccines have become a public health matter which is often debated among the community in spite of proven scientific evidence of their efficiency. A questionnaire was designed to evaluate the perception and knowledge of a population and compare it with behavior in order to assess a demographic within a sample population of 245 individuals selected at random within the United States, Here, we aim to clarify the difference between vaccine opinion among the general public as compared to vaccination status. Chi-squared analysis was done with the categorical data showing a statistically significant result when comparing parents versus non-parents, and Asian/Asian Americans against other ethnicities. All other comparisons were statistically insignificant. When looking at participant responses, PCPs did not discuss vaccines at all with 32% of the sample. The need for PCPs to provide educational information to certain ethnicities may play an important role in public health.

Exploring the Molecular Pathogenesis, Pathogen Association, and Therapeutic Strategies against HPV Infection

The human papillomavirus (HPV), commonly documented as the cause of warts, has gained much interest recently due to its possible links to several types of cancer. HPV infection is discussed in this review from multiple angles, including its virology, epidemiology, etiology, immunology, clinical symptoms, and treatment. Recent breakthroughs in molecular biology have led to the development of new methods for detecting and treating HPV in tissue. There is no cure for HPV, and although vaccines are available to prevent infection with the most common HPV viruses, their utilization is limited. Destruction and excision are the primary treatment modalities. This review sheds light on the epidemiology, molecular pathogenesis, the association of several other pathogens with HPV, the latest treatment strategies available to treat the same, and an overview of the progress made and the obstacles still to be overcome in the fight against HPV infection.

Vaccines for immunoprevention of cancer

The immunoprevention of cancer and cancer recurrence is an important area of concern for the scientific community and society as a whole. Researchers have been working for decades to develop vaccines with the potential to alleviate these health care and economic burdens. So far, vaccines have made more progress in preventing cancer than in eliminating already established cancer. In particular, vaccines targeting oncogenic viruses, such as the human papillomavirus and the hepatitis B virus, are exceptional examples of successful prevention of virus-associated cancers, such as cervical cancer and hepatocellular carcinoma. Cancer-preventive vaccines targeting nonviral antigens, such as tumor-associated antigens and neoantigens, are also being extensively tested. Here, we review the currently approved preventive cancer vaccines; discuss the challenges in this field by covering ongoing preclinical and clinical human trials in various cancers; and address various issues related to maximizing cancer vaccine benefit.

Public health impact and cost-effectiveness of a nine-valent gender-neutral HPV vaccination program in France

OBJECTIVES

In France, 9-valent HPV vaccination is recommended routinely for 11-14-years-old girls and as catch-up for 15-19-years-old girls. Recently, recommendation for gender-neutral vaccination (GNV) has been approved. The objectives of the study were to assess the public health impact and cost-effectiveness of a 9-valent GNV compared with girls-only vaccination program (GOV).

METHODS

A published HPV disease transmission dynamic model accounting for herd protection effects with a 100-year time horizon was adapted and calibrated to French data. Epidemiological and economic outcomes included disease cases averted and quality-adjusted life years (QALY). Costs and incremental cost-effectiveness ratio (ICER) were measured in 2018 Euros (€). A coverage rate of 26.2% among girls and boys was assumed for the GNV program based on the current female coverage rate in France. The base case included genital warts, cervical, vulvar, vaginal, and anal cancers. Scenario analyses included all HPV-related diseases and considered higher vaccination coverage rate (60%). Deterministic sensitivity analyses on key inputs were performed.

RESULTS

Over 100 years, GNV resulted in an additional reduction of 9,519 and 3,037 cervical cancer cases and deaths; 6,901 and 1,166 additional anal cancer cases and deaths; and a reduction of additional 1,284,077 genital warts compared with current GOV and an ICER of 24,763€/QALY. When including all HPV-related diseases, the ICER was 15,184€/QALY. At a higher coverage rate (60%), GNV would prevent 17,430 and 4,334 additional anogenital cancer cases and deaths and over two million genital warts compared with GOV with an ICER of 40,401€/QALY. Results were sensitive to a higher discount rate (6% versus 4%) and a shorter duration of protection (20 years versus lifetime).

CONCLUSIONS

In France, GNV has a significant impact in terms of public health benefits and may be considered cost-effective compared with GOV at low and high coverage rates.

Understanding of Young Adolescents About HPV Infection: How Health Education Can Improve Vaccination Rate

The purpose of this systematic review was to identify adolescents' awareness on the human papillomavirus (HPV), the HPV vaccine, and the willingness to undergo the vaccination. A systematic review of studies concerning the adolescent's knowledge and education on the admission of the HPV vaccine was carried out, through the Medline/PubMed and the Google Scholar databases, covering information on adolescent attitudes towards HPV vaccination, as well as their perceptions regarding the vaccination and the need for more training, towards the public information about the HPV and the HPV vaccine. This study concludes that adolescents are poorly informed about the HPV and the preventive vaccination issues, underestimating the likelihood of the infection by the virus. The way to improve their knowledge about the HPV and the implications of the HPV infection is to provide information through the framework of compulsory schooling, primary health care, and the development of informative interactive interventions. The awareness for the need of training about the HPV and its implications should be broadened to address the major barrier to vaccination, which is regarded to be the lack of adequate information. The knowledge and the perceptible susceptibility to the HPV infection and HPV-related diseases among adolescents demonstrate the need for a well-designed training program to bridge the gap of information about the HPV virus and to accept the HPV vaccine.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

TRIAL REGISTRATION NUMBER

NCT01824537.

Human Papillomavirus Vaccines: An Updated Review

Human papillomavirus (HPV) vaccines, which were introduced in many countries in the past decade, have shown promising results in decreasing HPV infection and related diseases, such as warts and precancerous lesions. In this review, we present the updated information about current HPV vaccines, focusing on vaccine coverage and efficacy. In addition, pan-gender vaccination and current clinical trials are also discussed. Currently, more efforts should be put into increasing the vaccine’s coverage, especially in low- and middle-income countries. Provision of education on HPV and vaccination is one of the most important methods to achieve this. Vaccines that target HPV types not included in current vaccines are the next stage in vaccine development. In the future, all HPV-related cancers, such as head and neck cancer, and anal cancer, should be tracked and evaluated, especially in countries that have introduced pan-gender vaccination programs. Therapeutic vaccines, in combination with other cancer treatments, should continue to be investigated.

Cost-effectiveness of a comprehensive immunization program serving high-risk, uninsured adults

Despite the numerous social and economic benefits of vaccination, adult immunization rates fall far short of recommended levels costing the United States $9 billion annually in health care expenditures and reduced productivity. While it is well recognized that childhood immunization is highly cost-effective, the economic impact of adult immunization programs varies by disease and is influenced by population demographics. This study aimed to assess the cost-effectiveness of a comprehensive adult immunization program serving high-need populations delivered by a local health department (LHD) in partnership with community organizations. We modeled incremental cost-effectiveness taking the payer perspective of each vaccine separately in simulated cohorts of 100,000 over a 20-year horizon using data provided by the LHD and data from the published literature. We adjusted the results to align with actual program delivery and used them to estimate an incremental cost-effectiveness ratio (ICER) for the entire program. We assessed the effects of varying our base model parameters in univariate sensitivity analyses. We discounted benefits and life years saved (LYS) at 3% and adjusted results to 2016 US$. Four of seven disease models were cost-effective (using a $100,000 CE threshold) with ICERS ranging from $14,260 to $79,022/LYS. Sensitivity analyses did not substantially impact the results. The ICER for program as a whole was $67,940/LYS. A community-delivered comprehensive immunization program serving uninsured, low income, high-risk adults is a cost-effective investment even when most do not receive the full regimen of some vaccines.

Knowledge, attitudes and practices of young people in Zimbabwe on cervical cancer and HPV, current screening methods and vaccination

BACKGROUND

The rise in cervical cancer trends in the past two decades has coincided with the human immunodeficiency virus (HIV) epidemic especially in the sub-Saharan African region. Young people (15 to 24 years old) are associated with many risk factors such as multiple sexual partners, early sexual debut, and high HIV incidences, which increase the chances of developing cervical cancer. The National Cancer Prevention and Control Strategy for Zimbabwe (2014-2018) highlights that no cancer communication strategy focusing on risk factors as primary cancer prevention. Therefore, the study aims to determine the knowledge, attitude and practices of young people in Zimbabwe on cervical cancer, screening, human papillomavirus (HPV) and vaccination.

METHODS

A cross-sectional survey assessing young people's knowledge, attitude and practices concerning cervical cancer was conducted in five provinces in Zimbabwe. A total of 751 young people were recruited through a three-stage cluster design from high schools and universities. Knowledge, attitudes and practices were assessed using questions based and adapted from the concepts of the Health Belief Model (HBM) and the Cervical Cancer Measuring tool kit-United Kingdom (UK).

RESULTS

Most young people, 87.47% (656/750) claimed to know what the disease called cervical cancer is, with a mean score of 89.98% [95% CI 73.71.11-96.64] between high school and 86.72% [95% CI 83.48-89.40] among university students. There was no significant difference in mean scores between high school and university students (p = 0.676). A risk factor knowledge proficiency score of ≥13 out of 26 was achieved in only 13% of the high school respondents and 14% of the university respondents with a broad range of misconceptions about cervical cancer risk factors in both females and males. There was not much difference on comprehensive knowledge of cervical cancer and its risk factors between female and male students, with the difference in knowledge scores among high school (p = 0.900) and university (p = 0.324) students not statistically significant. In contrast, 43% of respondents heard of cervical cancer screening and prevention, and 47% knew about HPV transmission and prevention. Parents' educational level, province and smoking, were some of the factors associated with knowledge of and attitude towards cervical among high school and university students.

CONCLUSION

This study revealed that young people in Zimbabwe have an idea about cervical cancer and the seriousness thereof, but they lack adequate knowledge of risk factors. Cervical cancer education and awareness emphasising causes, risk factors and care-seeking behaviours should be commissioned and strengthen at the community, provincial and national level. Developing a standard cervical cancer primary prevention tool that can be integrated into schools can be a step towards addressing health inequity.

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.

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

INTRODUCTION

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

AREAS COVERED

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

RESULTS

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

EXPERT COMMENTARY

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

Cost-effectiveness of adult vaccinations: A systematic review

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Ethical issues related to human papillomavirus vaccination programs: an example from Bangladesh

Background

Human Papilloma Virus (HPV) vaccine was introduced in Bangladesh through the arrangement of a demonstration project in Gazipur district in 2016, targeting grade five female students and non-school going girls (age range 10–12 years). HPV vaccination is expected to be eventually included in the nationwide immunization program if the demonstration project is successful. However, introduction and implementation of such a vaccination program raises various ethical concerns. This review paper illustrates a step by step assessment of the ethical concerns surrounding the HPV vaccination implementation in Bangladesh considering specific elements in administering and conducting the program as well as the intended results. Policy-makers, vaccine implementers, vaccine recipients, and an ethics specialist in Bangladesh were interviewed. Electronic database and websites have also been reviewed for relevant published literature and government statements.

Main body of the abstract

This program imparted inadequate knowledge about HPV and cervical cancer to the recipients and participants. There was lack of autonomous and informed choice of the girls and their parents about taking the vaccine. The program did not have any follow-up plan for the adverse effects in the long run. The impact of a female-only strategy in the larger societal context was overlooked. There was lack of awareness among the implementers about safeguarding the ethical issues pertaining to HPV vaccination.

Conclusion

Adolescent health education imparted in the scope of the vaccination program should contain adequate information about HPV, its mode of transmission, risk factors along with the importance of secondary prevention despite primary prevention. Adolescent boys should be given HPV related health education as well. The right of making informed choice should be appreciated and respected. More ethical discussion and debate should be done among the public health professionals of Bangladesh in order to increase awareness about ethical issues related to human health.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT COMMENTARY

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

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.

Ten Years of Human Papillomavirus Vaccination in the United States

Since human papillomavirus (HPV) vaccine was first introduced for females in the United States in 2006, vaccination policy has evolved as additional HPV vaccines were licensed and new data became available. The United States adopted a gender neutral routine HPV immunization policy in 2011, the first country to do so. Vaccination coverage is increasing, although it remains lower than for other vaccines recommended for adolescents. There are various reasons for low coverage, and efforts are ongoing to increase vaccine uptake. The safety profile of HPV vaccine has been well established from 10 years of postlicensure monitoring. Despite low coverage, the early effects of the HPV vaccination program have exceeded expectations.

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.

Systematic review of cost-effectiveness analyses for combinations of prevention strategies against human papillomavirus (HPV) infection: a general trend

BACKGROUND

Due to the arrival of multi-valent HPV vaccines, it is more and more important to have a better understanding of the relationship between vaccination and screening programmes. This review aimed to: (1) collect published evidence on the cost-effectiveness profile of different HPV prevention strategies and, in particular, those combining vaccination with changes in screening practices; (2) explore the cost-effectiveness of alternative preventive strategies based on screening and vaccination.

METHODS

A systematic literature review was conducted in order to identify the relevant studies regarding the cost-effectiveness of prevention strategies against HPV infection. Analysis comparing the modelling approaches between studies was made along with an assessment of the magnitude of impact of several factors on the cost-effectiveness of different screening strategies.

RESULTS

A total of 18 papers were quantitatively summarised within the narrative. A high degree of heterogeneity was found in terms of how HPV prevention strategies have been assessed in terms of their economic and epidemiological impact, with variation in screening practice and valence of HPV vaccination found to have large implications in terms of cost-effectiveness.

CONCLUSIONS

This review demonstrated synergies between screening and vaccination. New prevention strategies involving multi-valence vaccination, HPV DNA test screening, delayed commencement and frequency of screening could be implemented in the future. Strategies implemented in the future should be chosen with care, and informed knowledge of the potential impact of all possible prevention strategies. Highlighted in this review is the difficulty in assessing multiple strategies. Appropriate modelling techniques will need to be utilised to assess the most cost-effective strategies.

Prevention of eating disorders: A systematic review of randomized, controlled trials

OBJECTIVE

This systematic review evaluated the efficacy of universal, selective, and indicated eating disorder prevention.

METHOD

A systematic literature search was conducted in Medline, PsycINFO, Embase, Scopus, and the Cochrane Collaboration Library databases to January 2016. Studies were included if they were randomized, controlled trials (RCT) and tested an eating disorder prevention program. We retrieved 13 RCTs of universal prevention (N = 3,989 participants, 55% female, M age = 13.0 years), 85 RCTs of selective prevention (N = 11,949 participants, 99% female, M age = 17.6 years), and 8 RCTs of indicated prevention (N = 510 participants, 100% female, M age = 20.1 years). Meta-analysis was performed with selective prevention trials. As there were a limited number of universal and indicated trials, narrative synthesis was conducted.

RESULTS

Media literacy had the most support for universal prevention. Most universal approaches showed significant modest effects on risk factors. Dissonance-based was the best supported approach for selective prevention. Cognitive-behavior therapy (CBT), a healthy weight program, media literacy, and psychoeducation, were also effective for selective prevention and effects were maintained at follow-up. CBT was supported for indicated prevention and effects were maintained at follow-up.

DISCUSSION

The modest effects for universal prevention were likely due to floor effects. The evidence for selective prevention suggests that empirically supported approaches should be disseminated on a wider basis. Our findings suggest CBT should be offered for indicated populations. Overall, results suggest efficacy of several prevention programs for reducing risk for eating disorders, and that wider dissemination is required. © 2016 Wiley Periodicals, Inc.

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.

Adolescent Vaccination Strategies: Interventions to Increase Coverage

While vaccines have decreased the burden of disease, many adolescents still remain under-immunized, particularly for human papillomavirus (HPV) and influenza. We review the most current data regarding adolescent immunizations in the United States and discuss proven strategies that work for increasing vaccination rates. Strategies that have been shown to improve rates include provider feedback, immunization information systems (or registries), and enhanced access outside of provider offices, such as school-based immunization programs. Overall, practices may want to consider multimodal quality improvement approaches to enhance practice vaccination rates. The public health and cost benefits of immunizing adolescents are well known, yet recent measles outbreaks in the United States have highlighted issues with state immunization laws and vaccine refusals. Providers should be clear in their advice regarding vaccines and use effective reminder strategies as parents commonly cite not having enough information or knowledge that a vaccine was needed for their adolescent. Additional research is needed regarding adolescent consent for vaccines, as well as adolescent and parental refusal, in order to design systems that will help inform families and allow for widespread vaccine availability.

The impact and cost-effectiveness of nonavalent HPV vaccination in the United States: Estimates from a simplified transmission model

INTRODUCTION

The objective of this study was to assess the incremental costs and benefits of the 9-valent HPV vaccine (9vHPV) compared with the quadrivalent HPV vaccine (4vHPV). Like 4vHPV, 9vHPV protects against HPV types 6, 11, 16, and 18. 9vHPV also protects against 5 additional HPV types 31, 33, 45, 52, and 58.

METHODS

We adapted a previously published model of the impact and cost-effectiveness of 4vHPV to include the 5 additional HPV types in 9vHPV. The vaccine strategies we examined were (1) 4vHPV for males and females; (2) 9vHPV for females and 4vHPV for males; and (3) 9vHPV for males and females. In the base case, 9vHPV cost $13 more per dose than 4vHPV, based on available vaccine price information.

RESULTS

Providing 9vHPV to females compared with 4vHPV for females (assuming 4vHPV for males in both scenarios) was cost-saving regardless of whether or not cross-protection for 4vHPV was assumed. The cost per quality-adjusted life year (QALY) gained by 9vHPV for both sexes (compared with 4vHPV for both sexes) was < $0 (cost-saving) when assuming no cross-protection for 4vHPV and $8,600 when assuming cross-protection for 4vHPV.

CONCLUSIONS

Compared with a vaccination program of 4vHPV for both sexes, a vaccination program of 9vHPV for both sexes can improve health outcomes and can be cost-saving.

The Dynamics of HPV Infection and Cervical Cancer Cells

The development of cervical cells from normal cells infected by human papillomavirus into invasive cancer cells can be modeled using population dynamics of the cells and free virus. The cell populations are separated into four compartments: susceptible cells, infected cells, precancerous cells and cancer cells. The model system of differential equations also has a free virus compartment in the system, which infect normal cells. We analyze the local stability of the equilibrium points of the model and investigate the parameters, which play an important role in the progression toward invasive cancer. By simulation, we investigate the boundary between initial conditions of solutions, which tend to stable equilibrium point, representing controlled infection, and those which tend to unbounded growth of the cancer cell population. Parameters affected by drug treatment are varied, and their effect on the risk of cancer progression is explored.

Cost-Effectiveness Analysis of Universal Human Papillomavirus Vaccination Using a Dynamic Bayesian Methodology: The BEST II Study

BACKGROUND

Human papillomavirus (HPV) plays a role in the development of benign and malign neoplasms in both sexes. The Italian recommendations for HPV vaccines consider only females. The BEST II study (Bayesian modelling to assess the Effectiveness of a vaccination Strategy to prevent HPV-related diseases) evaluates 1) the cost-effectiveness of immunization strategies targeting universal vaccination compared with cervical cancer screening and female-only vaccination and 2) the economic impact of immunization on various HPV-induced diseases.

OBJECTIVE

The objective of this study was to evaluate whether female-only vaccination or universal vaccination is the most cost-effective intervention against HPV.

METHODS

We present a dynamic Bayesian Markov model to investigate transmission dynamics in cohorts of females and males in a follow-up period of 55 years. We assumed that quadrivalent vaccination (against HPV 16, 18, 6, and 11) is available for 12-year-old individuals. The model accounts for the progression of subjects across HPV-induced health states (cervical, vaginal, vulvar, anal, penile, and head/neck cancer as well as anogenital warts). The sexual mixing is modeled on the basis of age-, sex-, and sexual behavioral-specific matrices to obtain the dynamic force of infection.

RESULTS

In comparison to cervical cancer screening, universal vaccination results in an incremental cost-effectiveness ratio of €1,500. When universal immunization is compared with female-only vaccination, it is cost-effective with an incremental cost-effectiveness ratio of €11,600. Probabilistic sensitivity analysis shows a relatively large amount of parameter uncertainty, which interestingly has, however, no substantial impact on the decision-making process. The intervention being assessed seems to be associated with an attractive cost-effectiveness profile.

CONCLUSIONS

Universal HPV vaccination is found to be a cost-effective choice when compared with either cervical cancer screening or female-only vaccination within the Italian context.

Sexual behavior, risk perception, and HIV transmission can respond to HIV antiviral drugs and vaccines through multiple pathways

There has been growing use of highly active antiretroviral treatment (HAART) for HIV and significant progress in developing prophylactic HIV vaccines. The simplest theories of counterproductive behavioral responses to such interventions tend to focus on single feedback mechanisms: for instance, HAART optimism makes infection less scary and thus promotes risky sexual behavior. Here, we develop an agent based, age-structured model of HIV transmission, risk perception, and partner selection in a core group to explore behavioral responses to interventions. We find that interventions can activate not one, but several feedback mechanisms that could potentially influence decision-making and HIV prevalence. In the model, HAART increases the attractiveness of unprotected sex, but it also increases perceived risk of infection and, on longer timescales, causes demographic impacts that partially counteract HAART optimism. Both HAART and vaccination usually lead to lower rates of unprotected sex on the whole, but intervention effectiveness depends strongly on whether individuals over- or under-estimate intervention coverage. Age-specific effects cause sexual behavior and HIV prevalence to change in opposite ways in old and young age groups. For complex infections like HIV-where interventions influence transmission, demography, sexual behavior and risk perception-we conclude that evaluations of behavioral responses should consider multiple feedback mechanisms.

A home-school-doctor model to break the barriers for uptake of human papillomavirus vaccine

Background

A high coverage of human papillomavirus (HPV) vaccination is required to achieve a clinically significant reduction in disease burden. Countries implementing free-of-charge national vaccination program for adolescent girls are still challenged by the sub-optimal uptake rate. Voluntary on-site school-based mass vaccination programs have demonstrated high coverage. Here, we tested whether this could be an option for countries without a government-supported vaccination program as in Hong Kong.

Method

A Home-School-Doctor model was evolved based on extensive literature review of various health promotion models together with studies on HPV vaccination among adolescent girls. The outcome measure was uptake of vaccination. Factors associated with the outcome were measured by validated surveys in which 4,631 students from 24 school territory wide participated. Chi-square test was used to analyze association between the categorical variables and the outcome. Multivariate analysis was performed to identify independent variables associated with the outcome with vaccine group as case and non-vaccine group as control.

Results

In multivariate analysis, parental perception of usefulness of the Home-School-Doctor model had a very high odds ratio for uptake of HPV vaccination (OR 26.6, 95 % CI 16.4, 41.9). Paying a reasonable price was another independent factor associated with increased uptake (OR 1.71, 95 % CI 1.39, 2.1 for those with parents willing to pay US$125-250 for vaccination). For parents and adolescents who were not sure where to get vaccination, this model was significantly associated with improved uptake rate (OR 1.66, 95 % CI 1.23, 2.23). Concerns with side effects of vaccine (OR 0.70, 95 % CI 0.55, 0.88), allowing daughters to make their own decisions (OR 0.49, 95 % CI 0.38, 0.64) and not caring much about daughters’ social life (95 % CI 0.45, 0.92) were factors associated with a lower uptake.

Discussion

The findings of this study have added knowledge on how a school-based vaccination program would improve vaccine uptake rate even when the users need to pay. Our findings are consistent with other study that the most acceptable way to achieve high uptake of HPV vaccine is to offer voluntary school-based vaccination.

Conclusion

A model of care incorporating the efforts and expertise of academics and health professionals working closely with school can be applied to improve the uptake of vaccine among adolescent girls. Subsidized voluntary school-based vaccination scheme can be an option.

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

Background

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

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

Methods

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

Results

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

Conclusions

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

Could the human papillomavirus vaccines drive virulence evolution?

The human papillomavirus (HPV) vaccines hold great promise for preventing several cancers caused by HPV infections. Yet little attention has been given to whether HPV could respond evolutionarily to the new selection pressures imposed on it by the novel immunity response created by the vaccine. Here, we present and theoretically validate a mechanism by which the vaccine alters the transmission-recovery trade-off that constrains HPV's virulence such that higher oncogene expression is favoured. With a high oncogene expression strategy, the virus is able to increase its viral load and infected cell population before clearance by the vaccine, thus improving its chances of transmission. This new rapid cell-proliferation strategy is able to circulate between hosts with medium to high turnover rates of sexual partners. We also discuss the importance of better quantifying the duration of challenge infections and the degree to which a vaccinated host can shed virus. The generality of the models presented here suggests a wider applicability of this mechanism, and thus highlights the need to investigate viral oncogenicity from an evolutionary perspective.

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

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

Direct benefit of vaccinating boys along with girls against oncogenic human papillomavirus: bayesian evidence synthesis

OBJECTIVE

To assess the reduction in the vaccine preventable burden of cancer in men if boys are vaccinated along with girls against oncogenic human papillomavirus (HPV).

DESIGN

Bayesian evidence synthesis approach used to evaluate the impact of vaccination against HPV types 16 and 18 on the burden of anal, penile, and oropharyngeal carcinomas among heterosexual men and men who have sex with men. The reduced transmission of vaccine-type HPV from vaccination of girls was assumed to lower the risk of HPV associated cancer in all men but not to affect the excess risk of HPV associated cancers among men who have sex with men.

SETTING

General population in the Netherlands.

INTERVENTION

Inclusion of boys aged 12 into HPV vaccination programmes.

MAIN OUTCOME MEASURES

Quality adjusted life years (QALYs) and numbers needed to vaccinate.

RESULTS

Before HPV vaccination, 14.9 (95% credible interval 12.2 to 18.1) QALYs per thousand men were lost to vaccine preventable cancers associated with HPV in the Netherlands. This burden would be reduced by 37% (28% to 48%) if the vaccine uptake among girls remains at the current level of 60%. To prevent one additional case of cancer among men, 795 boys (660 to 987) would need to be vaccinated; with tumour specific numbers for anal, penile, and oropharyngeal cancer of 2162, 3486, and 1975, respectively. The burden of HPV related cancer in men would be reduced by 66% (53% to 805) if vaccine uptake among girls increases to 90%. In that case, 1735 boys (1240 to 2900) would need to be vaccinated to prevent an additional case; with tumour specific numbers for anal, penile, and oropharyngeal cancer of 2593, 29107, and 6484, respectively.

CONCLUSIONS

Men will benefit indirectly from vaccination of girls but remain at risk of cancers associated with HPV. The incremental benefit of vaccinating boys when vaccine uptake among girls is high is driven by the prevention of anal carcinomas, which underscores the relevance of HPV prevention efforts for men who have sex with men.

Revisiting the cost-effectiveness of universal HPV-vaccination in Denmark accounting for all potentially vaccine preventable HPV-related diseases in males and females

Objective

The purpose of this study was to assess the consequences of a national immunization program with HPV vaccine for both boys and girls in Denmark, including the prophylactic effects on all potentially vaccine preventable HPV-associated diseases in male and female.

Methods

The study focussed on the quadrivalent vaccine which protects against HPV type 6, 11, 16 and 18, and the vaccine’s protection against genital warts, cervical intraepithelial neoplasia, cervical cancer, anogenital cancer (anal, penile, vaginal and vulvar cancer) and head and neck cancer (oral cavity, oropharyngeal, hypopharyngeal and laryngeal cancer) were included in the analyses. In general, the analysis was performed in two phases. First, an agent-based transmission model that described the HPV transmission without and with HPV vaccination was applied. Second, an analysis of the incremental costs and effects was performed. The model did not include naturally-acquired immunity to HPV in the simulations.

Results

In the base case result (i.e. vaccination of girls only, 85% vaccination rate, private market price at € 123 per dose ex. VAT) an ICER of 3583 €/QALY (3-dose regime) is estimated when all HPV-related diseases are taken into account. Vaccination of girls & boys vs. vaccination of girls only an ICER of 28,031 €/QALY (2-dose regime) and 41,636 €/QALY (3-dose regime) is estimated.

Conclusions

Extension of the current HPV programme in Denmark to include boys and girls is a cost effective preventive intervention that would lead to a faster prevention of cancers, cancer precursors and genital warts in men and women.

Impact of coverage-dependent marginal costs on optimal HPV vaccination strategies

The effectiveness of vaccinating males against the human papillomavirus (HPV) remains a controversial subject. Many existing studies conclude that increasing female coverage is more effective than diverting resources into male vaccination. Recently, several empirical studies on HPV immunization have been published, providing evidence of the fact that marginal vaccination costs increase with coverage. In this study, we use a stochastic agent-based modeling framework to revisit the male vaccination debate in light of these new findings. Within this framework, we assess the impact of coverage-dependent marginal costs of vaccine distribution on optimal immunization strategies against HPV. Focusing on the two scenarios of ongoing and new vaccination programs, we analyze different resource allocation policies and their effects on overall disease burden. Our results suggest that if the costs associated with vaccinating males are relatively close to those associated with vaccinating females, then coverage-dependent, increasing marginal costs may favor vaccination strategies that entail immunization of both genders. In particular, this study emphasizes the necessity for further empirical research on the nature of coverage-dependent vaccination costs.

Knowledge and Perceptions of HPV and the HPV Vaccine among Pre-adolescent Girls and Their Guardians in Georgetown, Guyana

OBJECTIVES

To examine the knowledge and perceptions of 11-year old girls and their guardians toward the human papillomavirus (HPV), HPV (mandatory) vaccination and cervical cancer and to determine their main sources of health information.

METHODS

A cross-sectional study was done by interviewing two separate study populations ie 11-year old girls from five primary schools in Georgetown and their guardians. Questions were designed to assess level of knowledge as well as perceptions about mandatory vaccination and sources of health information.

RESULTS

A total of 87 girls participated, of whom 10 (11%) had already received the HPV vaccine. Overall, when asked whether they knew of HPV, the HPV vaccine, cervical cancer or the Pap smear, more than half of the girls, in every instance, did not know. Seventy-four guardians took part and most (> 80%) of them claimed that they knew about these parameters except for HPV transmission (40%) and the cause of cervical cancer (30%). Both girls and guardians responded poorly to questions about the detection of cervical cancer. Furthermore, only two of the 14 girls who stated that they knew how HPV was transmitted, actually answered correctly that it was sexual transmission. Girls were almost twice as likely to be in favour of mandatory vaccination as guardians (OR 1.8, 95% CI: 0.9, 3.6) but the difference was not significant (p > 0.05). The girls indicated health centres/clinics (58%), whilst TV/radio (66%) was the preference for the guardians as their most popular health information sources.

CONCLUSIONS

These findings point to a necessity for educational programmes and activities in which children and their guardians can meaningfully participate and be informed about the different aspects of HPV vaccination.

Applying a Simple Model of Cost Effectiveness Study of HPV Vaccine for Iran

HPV vaccine has been recently added to the Iran Drug List, so decision makers need information beyond that available from RCTs to recommend funding for this vaccination. Modeling and economic studies have addressed some of those information needs. We reviewed cost effectiveness studies to find a suitable model for Iranian population to determine the potential cost effectiveness of HPV vaccine program based on domestic available epidemiologic data. Articles were obtained from an extensive literature search to determine the cost effectiveness of implementing an HPV vaccination program with routine cervical cancer screening. A total of 64 studies were included in this review. Although the studies used different model structures, baseline parameters and assumptions (either a Markov, Hybrid, or Dynamic model). Most of the proposed cost effectiveness models need to model the probability of HPV acquisition, the possible progression from HPV infection to CIN I, CIN II, CIN III and cervical cancer, the probability of HPV transmission which are not available in Iranian epidemiologic data. Based on the available epidemiologic data in Iran, the simplified and it requires substantially fewer assumptions than the other more complex Markov and hybrid models, therefore we decided to use this model for the evaluation of cost effectiveness of HPV vaccine in Iran.

Update on prevention and screening of cervical cancer

Cervical cancer is the third most common cause of cancer in women in the world. During the past few decades tremendous strides have been made toward decreasing the incidence and mortality of cervical cancer with the implementation of various prevention and screening strategies. The causative agent linked to cervical cancer development and its precursors is the human papillomavirus (HPV). Prevention and screening measures for cervical cancer are paramount because the ability to identify and treat the illness at its premature stage often disrupts the process of neoplasia. Cervical carcinogenesis can be the result of infections from multiple high-risk HPV types that act synergistically. This imposes a level of complexity to identifying and vaccinating against the actual causative agent. Additionally, most HPV infections spontaneously clear. Therefore, screening strategies should optimally weigh the benefits and risks of screening to avoid the discovery and needless treatment of transient HPV infections. This article provides an update of the preventative and screening methods for cervical cancer, mainly HPV vaccination, screening with Pap smear cytology, and HPV testing. It also provides a discussion of the newest United States 2012 guidelines for cervical cancer screening, which changed the age to begin and end screening and lengthened the screening intervals.

An updated natural history model of cervical cancer: derivation of model parameters

Mathematical models of cervical cancer have been widely used to evaluate the comparative effectiveness and cost-effectiveness of preventive strategies. Major advances in the understanding of cervical carcinogenesis motivate the creation of a new disease paradigm in such models. To keep pace with the most recent evidence, we updated a previously developed microsimulation model of human papillomavirus (HPV) infection and cervical cancer to reflect 1) a shift towards health states based on HPV rather than poorly reproducible histological diagnoses and 2) HPV clearance and progression to precancer as a function of infection duration and genotype, as derived from the control arm of the Costa Rica Vaccine Trial (2004-2010). The model was calibrated leveraging empirical data from the New Mexico Surveillance, Epidemiology, and End Results Registry (1980-1999) and a state-of-the-art cervical cancer screening registry in New Mexico (2007-2009). The calibrated model had good correspondence with data on genotype- and age-specific HPV prevalence, genotype frequency in precancer and cancer, and age-specific cancer incidence. We present this model in response to a call for new natural history models of cervical cancer intended for decision analysis and economic evaluation at a time when global cervical cancer prevention policy continues to evolve and evidence of the long-term health effects of cervical interventions remains critical.