Health and economic outcomes of HPV 16,18 vaccination in 72 GAVI-eligible countries

Economic and humanistic burden of external genital warts

External genital warts (EGW) are a sexually transmitted infection caused by various strains of human papillomavirus (HPV). Several studies have described the direct and indirect costs of EGW, while others have reported on the burden of EGW in terms of the impact on the quality of life (QOL) of patients. The arrival of a quadrivalent HPV vaccine that protects against both cervical cancer and EGW requires a proper understanding of the impact of vaccines on costs and QOL. Using pre-defined search terms and inclusion/exclusion criteria, we performed a systematic review of the economic and humanistic burden of EGW. The focus of our review was on literature describing the direct and indirect costs of EGW per episode of care (EoC) or per year, as well as the impact of EGW on disease-specific, generic, or preference-based QOL measures. We also reviewed the literature on the national economic burden of EGW from the perspectives of different countries. Other aspects of EGW management that can inform economic modelling studies, such as length of EoC, number of physician visits and indirect costs, were also explored. Our review sheds light on the high economic and humanistic burden of EGW and important differences in the costs between men and women, as well as the differences in health resource utilization and costs across countries. Our study also highlights the dearth of information on the impact of EGW on the QOL and productivity of patients.

Health economics of screening for gynaecological cancers

In this chapter, we summarise findings from recent cost-effectiveness analyses of screening for cervical cancer and ovarian cancer. We begin with a brief summary of key issues that affect the cost-effectiveness of screening, including disease burden, and availability and type of screening tests. For cervical cancer, we discuss the potential effect of human papilloma virus vaccines on screening. Outstanding epidemiological and cost-effectiveness issues are included. For cervical cancer, this includes incorporating the long-term effect of treatment (including adverse birth outcomes in treated women who are of reproductive age) into cost-effectiveness models using newly available trial data to identify the best strategy for incorporating human papilloma virus tests. A second issue is the need for additional data on human papilloma virus vaccines, such as effectiveness of reduced cancer incidence and mortality, effectiveness in previously exposed women and coverage. Definitive data on these parameters will allow us to update model-based analyses to include more realistic estimates, and also potentially dramatically alter our approach to screening. For ovarian cancer, outstanding issues include confirming within the context of a trial that screening is effective for reducing mortality and incorporating tests with high specificity into screening into screening algorithms for ovarian cancer.

Sex-specific immunization for sexually transmitted infections such as human papillomavirus: insights from mathematical models

BACKGROUND

Sex-specific differences regarding the transmissibility and the course of infection are the rule rather than the exception in the epidemiology of sexually transmitted infections (STIs). Human papillomavirus (HPV) provides an example: disease outcomes differ between men and women, as does the potential for transmission to the opposite sex. HPV vaccination of preadolescent girls was recently introduced in many countries, and inclusion of boys in the vaccination programs is being discussed. Here, we address the question of whether vaccinating females only, males only, or both sexes is the most effective strategy to reduce the population prevalence of an STI like HPV.

METHODS AND FINDINGS

We use a range of two-sex transmission models with varying detail to identify general criteria for allocating a prophylactic vaccine between both sexes. The most effective reduction in the population prevalence of infection is always achieved by single-sex vaccination; vaccinating the sex with the highest prevaccine prevalence is the preferred strategy in most circumstances. Exceptions arise only when the higher prevaccine prevalence is due to a substantially lower rate of natural immunity, or when natural immunity is lifelong, and a prolonged duration of infectiousness coincides with increased transmissibility. Predictions from simple models were confirmed in simulations based on an elaborate HPV transmission model. Our analysis suggests that relatively inefficient genital transmission from males to females might render male vaccination more effective in reducing overall infection levels. However, most existing HPV vaccination programs have achieved sufficient coverage to continue with female-only vaccination.

CONCLUSIONS

Increasing vaccine uptake among preadolescent girls is more effective in reducing HPV infection than including boys in existing vaccination programs. As a rule, directing prophylactic immunization at the sex with the highest prevaccine prevalence results in the largest reduction of the population prevalence.

Cost-effectiveness analysis for Pap smear screening and human papillomavirus DNA testing and vaccination

INTRODUCTION

As the effectiveness of cytology-based screening programme for cervical cancer in mortality reduction has reached a plateau, various preventive strategies have been considered, including intensive Pap smear screening and the supplemental use of human papillomavirus (HPV) DNA test or HPV vaccination. Cost and effectiveness of these various preventive strategies are therefore of great concern for health policy makers.

OBJECTIVE

We intended to assess whether the combination of HPV DNA testing or HPV vaccination with Pap smear screening programme or the sole annual Pap smear screening is more effective and cost-effective in prevention of cervical cancer than the existing triennial Pap smear screening programme.

METHODS

A Markov decision model was constructed to compare total costs and effectiveness between different preventive strategies (including annual Pap smear, HPV DNA testing or HPV vaccination together with Pap smear screening programme) as opposed to the triennial Pap smear screening alone (the comparator). Probabilistic cost-effectiveness (C-E) analysis was adopted to plot a series of simulated incremental C-E ratios scattered over C-E plane and also to yield the acceptability curve for different comparisons of strategies. The threshold of vaccine cost and the influence of attendance rate were also investigated.

RESULTS

Compared with triennial Pap smear screening programme, most of preventive strategies cost more but gain additional life years (quadrant I of C-E plane) except HPV DNA testing with Pap smear every 5 years dominated by triennial Pap smear screening programme. The most cost-effective strategy was annual Pap smear (incremental C-E ratio = $31 698), followed by HPV DNA testing with Pap smear every 3 years ($36 627), and vaccination programme with triennial Pap smear screening ($44 688) with the corresponding cost-effective probabilities by the acceptability curve being 65.52%, 52.08% and 35.84% given the threshold of $40 000 of willingness to pay. Vaccination combined with triennial Pap smear would be as cost-effective as annual Pap smear provided the cost of vaccination was lowered to $250 per full course of injection.

CONCLUSIONS

Among various preventive strategies annual Pap smear screening programme is still the most cost-effective and additional HPV DNA testing is a cost-effective choice under a reasonable threshold of willingness to pay. Vaccination programme in combination with triennial screening would be cost-effective if vaccine cost can be greatly reduced in a large economic scale.

Human papillomavirus vaccine delivery strategies that achieved high coverage in low- and middle-income countries

OBJECTIVE

To assess human papillomavirus (HPV) vaccination coverage after demonstration projects conducted in India, Peru, Uganda and Viet Nam by PATH and national governments and to explore the reasons for vaccine acceptance or refusal.

METHODS

Vaccines were delivered through schools or health centres or in combination with other health interventions, and either monthly or through campaigns at fixed time points. Using a two-stage cluster sample design, the authors selected households in demonstration project areas and interviewed over 7000 parents or guardians of adolescent girls to assess coverage and acceptability. They defined full vaccination as the receipt of all three vaccine doses and used an open-ended question to explore acceptability.

FINDINGS

Vaccination coverage in school-based programmes was 82.6% (95% confidence interval, CI: 79.3-85.6) in Peru, 88.9% (95% CI: 84.7-92.4) in 2009 in Uganda and 96.1% (95% CI: 93.0-97.8) in 2009 in Viet Nam. In India, a campaign approach achieved 77.2% (95% CI: 72.4-81.6) to 87.8% (95% CI: 84.3-91.3) coverage, whereas monthly delivery achieved 68.4% (95% CI: 63.4-73.4) to 83.3% (95% CI: 79.3-87.3) coverage. More than two thirds of respondents gave as reasons for accepting the HPV vaccine that: (i) it protects against cervical cancer; (ii) it prevents disease, or (iii) vaccines are good. Refusal was more often driven by programmatic considerations (e.g. school absenteeism) than by opposition to the vaccine.

CONCLUSION

High coverage with HPV vaccine among young adolescent girls was achieved through various delivery strategies in the developing countries studied. Reinforcing positive motivators for vaccine acceptance is likely to facilitate uptake.

Epidemiology and burden of HPV infection and related diseases: implications for prevention strategies

Human papillomavirus (HPV) infection is a necessary, although not sufficient cause of cervical cancer. Globally, HPV infection accounts for an estimated 530,000 cervical cancer cases (~270,000 deaths) annually, with the majority (86% of cases, 88% of deaths) occurring in developing countries. Approximately 90% of anal cancers and a smaller subset (<50%) of other cancers (oropharyngeal, penile, vaginal, vulvar) are also attributed to HPV. In total, HPV accounts for 5.2% of the worldwide cancer burden. HPVs 16 and 18 are responsible for 70% of cervical cancer cases and, especially HPV 16, for a large proportion of other cancers. Prophylactic vaccination targeting these genotypes is therefore expected to have a major impact on the burden of cervical cancer as well as that of other HPV-related cancers. Over the past 50 years, organized or opportunistic screening with Papanicolaou (Pap) cytology has led to major reductions in cervical cancer in most developed countries. However, due to lack of resources or inadequate infrastructure, many countries have failed to reduce cervical cancer mortality through screening. HPV DNA testing recently emerged as a likely candidate to replace Pap cytology for primary screening. It is less prone to human error and more sensitive than Pap in detecting high-grade cervical lesions. For countries with national vaccination programs, HPV testing may also serve as a low cost strategy to monitor long term vaccine efficacy. Introduction of well organized vaccination and screening programs should be a priority for all countries. Increased support from donors is needed to support this cause.

Health and economic impact of HPV 16/18 vaccination and cervical cancer screening in Eastern Africa

Eastern Africa has the world's highest cervical cancer incidence and mortality rates. We used epidemiologic data from Kenya, Mozambique, Tanzania, Uganda, and Zimbabwe to develop models of HPV-related infection and disease. For each country, we assessed HPV vaccination of girls before age 12 followed by screening with HPV DNA testing once, twice, or three times per lifetime (at ages 35, 40, 45). For women over age 30, we assessed only screening (with HPV DNA testing up to three times per lifetime or VIA at age 35). Assuming no waning immunity, mean reduction in lifetime cancer risk associated with vaccination ranged from 36 to 45%, and vaccination followed by screening once per lifetime at age 35 with HPV DNA testing ranged from 43 to 51%. For both younger and older women, the most effective screening strategy was HPV DNA testing three times per lifetime. Provided the cost per vaccinated girl was less than I$10 (I$2 per dose), vaccination had an incremental cost-effectiveness ratio [I$ (international dollars)/year of life saved (YLS)] less than the country-specific per capita GDP, a commonly cited heuristic for "very cost-effective" interventions. If the cost per vaccinated girl was between I$10 (I$2 per dose) and I$25 (I$5 per dose), vaccination followed by HPV DNA testing would save the most lives and would be considered good value for public health dollars. These results should be used to catalyze design and evaluation of HPV vaccine delivery and screening programs, and contribute to a dialogue on financing HPV vaccination in poor countries.

AS04-adjuvanted human papillomavirus (HPV) types 16 and 18 vaccine (Cervarix®): a review of its use in the prevention of premalignant cervical lesions and cervical cancer causally related to certain oncogenic HPV types

The AS04-adjuvanted human papillomavirus (HPV) 16/18 vaccine (Cervarix®) is a noninfectious recombinant vaccine produced using purified virus-like particles (VLPs) that induce a strong immunogenic response eliciting high levels of anti-L1 VLP antibodies that persist at levels markedly greater than those observed with natural infection. The vaccine adjuvant (AS04) is composed of monophosphoryl-lipid A, which enhances cellular and humoral immune response, adsorbed to aluminium hydroxide. The vaccine is indicated for the prevention of premalignant cervical lesions and cervical cancer causally related to certain oncogenic HPV types in females aged ≥10 years. The AS04-adjuvanted HPV 16/18 vaccine administered in a three-dose schedule over 6 months elicits a high immunogenic response and is highly protective against cervical intraepithelial neoplasia and infection causally related to high-risk oncogenic HPV types. In well designed clinical trials in young women aged 15-25 years who were HPV 16/18 seronegative and DNA negative to 14 HPV high-risk types, high levels of immunogenicity and protection were sustained for follow-up periods of up to 8.4 years. High and persistent immunogenicity against infection with HPV 16/18 has also been demonstrated in older and younger females (aged 10-55 years) who were seronegative for vaccine HPV types. The AS04-adjuvanted HPV 16/18 vaccine elicited a greater immunogenic response than the quadrivalent HPV vaccine in women aged 18-45 years who were seronegative and DNA negative for HPV 16/18. The AS04-adjuvanted HPV 16/18 vaccine confers cross protection against certain non-vaccine, high-risk HPV types. A rapid and strong anamnestic humoral immune response was elicited following a fourth dose of the vaccine. The AS04-adjuvanted HPV 16/18 vaccine is generally well tolerated, and pharmacoeconomic analyses have demonstrated the potential for public health benefits and cost effectiveness when vaccination programmes are run in conjunction with screening programmes. Thus, the AS04-adjuvanted HPV 16/18 vaccine prevents cervical disease associated with certain oncogenic HPV types, thereby reducing the burden of premalignant cervical lesions and, very likely, cervical cancer.

Comparative evaluation of the potential impact of rotavirus versus HPV vaccination in GAVI-eligible countries: a preliminary analysis focused on the relative disease burden

BACKGROUND

Immunization policymakers at global and local levels need to establish priorities among new vaccines competing for limited resources. However, comparison of the potential impact of single vaccination programs is challenging, primarily due to the limited number of vaccine analyses as well as their differing analytic approaches and reporting formats. The purpose of this study is to provide early insight into how the comparative impact of different new vaccines could be assessed in resource-poor settings with respect to affordability, cost-effectiveness, and distributional equity.

METHODS

We compared the health, economic, and financial consequences of introducing the two vaccines in 72 GAVI-eligible countries using a number of different outcome measures to evaluate affordability, cost-effectiveness, and distributional equity. We use simple static models to standardize the analytic framework and improve comparability between the two new vaccines. These simple models were validated by leveraging previously developed, more complex models for rotavirus and human papillomavirus (HPV).

RESULTS

With 70% coverage of a single-age cohort of infants and pre-adolescent girls, the lives saved with rotavirus (~274,000) and HPV vaccines (~286,000) are similar, although the timing of averted mortality differs; rotavirus-attributable deaths occur in close proximity to infection, while HPV-related cancer deaths occur largely after age 30. Deaths averted per 1000 vaccinated are 5.2 (rotavirus) and 12.6 (HPV). Disability-adjusted life years (DALYs) averted were ~7.15 million (rotavirus) and ~1.30 million (HPV), reflecting the greater influence of discounting on the latter, given the lagtime between vaccination and averted cancer. In most countries (68 for rotavirus and 66 for HPV, at the cost of I$25 per vaccinated individual) the incremental cost per DALY averted was lower than each country's GDP per capita. Financial resources required for vaccination with rotavirus are higher than with HPV since both genders are vaccinated.

CONCLUSIONS

While lifesaving benefits of rotavirus and HPV vaccines will be realized at different times, the number of lives saved over each target populations' lifetimes will be similar. Model-based analyses that use a standardized analytic approach and generate comparable outputs can enrich the priority-setting dialogue. Although new vaccines may be deemed cost-effective, other factors including affordability and distributional equity need to be considered in different settings. We caution that for priority setting in an individual country, more rigorous comparisons should be performed, using more comprehensive models and considering all relevant vaccines and delivery strategies.

Mothers' preferences and willingness to pay for HPV vaccines in Vinh Long Province, Vietnam

About 530,000 women develop cervical cancer worldwide and 275,000 die from the disease each year. Eighty percent of these deaths occur in developing countries. In Vietnam, cervical cancer has recently emerged as the most common type of cancer in women, and there are no national screening programs for cervical cancer. Since 2009, two different human papillomavirus (HPV) vaccines have been licensed for use in Vietnam, but access to these vaccines is generally limited to people who live in urban areas. Studies have shown that HPV vaccination may be cost-effective in cervical cancer prevention in Vietnam, depending on vaccination costs. Given that current HPV vaccines are expensive and public health funding for supporting a rapid introduction of the vaccine is limited, expanding and sustaining access to the HPV vaccine may require alternative financing mechanisms, such as fees-based immunization services. A conjoint analysis study was conducted with mothers of girls 9-17 years of age in Vinh Long Province in Vietnam to estimate the mothers' demand for HPV vaccines for their daughters and to measure the tradeoffs between vaccine fees and vaccine uptake. The results suggest that the demand for HPV vaccines was high, increased with vaccine effectiveness and duration of effectiveness, and decreased with vaccine cost. Vaccine effectiveness was the most important vaccine attribute to these mothers, followed by duration of effectiveness. The predicted probability of respondents buying an HPV vaccine that was 70% effective for 10 years varied by the price, ranging from 30% when the vaccine price was $353 per course, to 68% when the vaccine cost $6 per course. As expected, demand and predicted purchase probability were higher among groups with higher socioeconomic status.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

HPV vaccine acceptability in Ghana, West Africa

OBJECTIVE

Cervical cancer is a leading cause of cancer-related mortality among women in Ghana. As of this writing no data are available concerning knowledge, attitudes and acceptability of human papillomavirus (HPV) vaccination by women in Ghana.

METHODS

Between November and December 2009, a self-administered survey was used to elicit information from 264 Ghanaian women, ages 18-65.

RESULTS

Overall, 40% had heard about HPV vaccine and 94% were willing to vaccinate themselves or their daughters. Ideal age for vaccination was 12.7 years. Most women (75%) thought the vaccine should be received regardless of one's number of sex partners. The most prevalent concerns were whether the vaccine would be administered safely using clean needles (82%), and possible future side effects (77%). Concerns about cost and vaccine encouraging earlier sex were reported by nearly half. Significant barriers to vaccine acceptance were women's lack of knowledge about the gravity of cervical cancer in Ghana and utility of Pap test in detecting it, low perceived risk for cervical cancer, low social support to vaccine use, and low self-efficacy to find a doctor or clinic to get vaccinated (p<05). About 55% of the women did not know the vaccine only works among those who are not yet infected with HPV. Schools and television were the most preferred methods of educating the public and cervical cancer prevention ranked as the ideal message (80%). Most respondents believed the decision to vaccinate their daughter should be made by both parents (34%) or in conjunction with the daughter (37%), as opposed to the government (17%).

CONCLUSIONS

Educational programs addressing specific barriers identified in the current study have the potential to significantly improve HPV vaccine uptake in Ghana.

Worldwide burden of cervical cancer in 2008

BACKGROUND

The knowledge that persistent human papillomavirus infection is the main cause of cervical cancer has resulted in the development of assays that detect nucleic acids of the virus and prophylactic vaccines. Up-to-date and reliable data are needed to assess impact of existing preventive measures and to define priorities for the future.

MATERIALS AND METHODS

Best estimates on cervical cancer incidence and mortality are presented using recently compiled data from cancer and mortality registries for the year 2008.

RESULTS

There were an estimated 530,000 cases of cervical cancer and 275,000 deaths from the disease in 2008. It is the third most common female cancer ranking after breast (1.38 million cases) and colorectal cancer (0.57 million cases). The incidence of cervical cancer varies widely among countries with world age-standardised rates ranging from <1 to >50 per 100,000. Cervical cancer is the leading cause of cancer-related death among women in Eastern, Western and Middle Africa; Central America; South-Central Asia and Melanesia. The highest incidence rate is observed in Guinea, with ∼6.5% of women developing cervical cancer before the age of 75 years. India is the country with the highest disease frequency with 134,000 cases and 73 000 deaths. Cervical cancer, more than the other major cancers, affects women <45 years.

CONCLUSIONS

In spite of effective screening methods, cervical cancer continues to be a major public health problem. New methodologies of cervical cancer prevention should be made available and accessible for women of all countries through well-organised programmes.

Eurogin 2010 roadmap on cervical cancer prevention

The EUROGIN 2010 roadmap represents a continuing effort to provide and interpret updated information on cervical cancer screening and vaccination against the cause of the disease, high-risk human papillomavirus (HPV). Contrary to the two previous reports in 2008 and 2009, the present roadmap gives equal room to HPV-based screening and HPV vaccination, as a result of the recent strengthening of the evidence on the efficacy and feasibility of both approaches. The superiority of HPV testing in primary screening compared to cytology (in more developed countries) and to cytology or visual inspection methods (in less developed countries) has been demonstrated in several randomised trials. High vaccine efficacy has been confirmed up to 7 years after vaccination; school-based programmes in some countries have been able to reach over 70% coverage among adolescent girls. Demonstration projects have indicated that the delivery of HPV vaccines in less developed countries is feasible and favourably received by populations where cervical cancer is very common. HPV-based screening can diminish cervical cancer incidence more quickly than HPV vaccination, but vaccination can eventually facilitate screening efforts, especially if new vaccines against a greater number of HPV types are introduced. The availability of two highly complementary prevention tools such as HPV testing and HPV vaccination makes it possible to conceive integrated strategies for the elimination of cervical cancer that have no precedent in the cancer field. HPV tests and HPV vaccines remain, however, too expensive, and large-scale financing of screening and vaccination in less developed countries is sorely lacking.

Economic impact of dengue illness in the Americas

The growing burden of dengue in endemic countries and outbreaks in previously unaffected countries stress the need to assess the economic impact of this disease. This paper synthesizes existing studies to calculate the economic burden of dengue illness in the Americas from a societal perspective. Major data sources include national case reporting data from 2000 to 2007, prospective cost of illness studies, and analyses quantifying underreporting in national routine surveillance systems. Dengue illness in the Americas was estimated to cost $2.1 billion per year on average (in 2010 US dollars), with a range of $1-4 billion in sensitivity analyses and substantial year to year variation. The results highlight the substantial economic burden from dengue in the Americas. The burden for dengue exceeds that from other viral illnesses, such as human papillomavirus (HPV) or rotavirus. Because this study does not include some components (e.g., vector control), it may still underestimate total economic consequences of dengue.

Costs of cervical cancer screening and treatment using visual inspection with acetic acid (VIA) and cryotherapy in Ghana: the importance of scale

OBJECTIVES

To estimate the incremental costs of visual inspection with acetic acid (VIA) and cryotherapy at cervical cancer screening facilities in Ghana; to explore determinants of costs through modelling; and to estimate national scale-up and annual programme costs.

METHODS

Resource-use data were collected at four out of six active VIA screening centres, and unit costs were ascertained to estimate the costs per woman of VIA and cryotherapy. Modelling and sensitivity analysis were used to explore the influence of observed differences between screening facilities on estimated costs and to calculate national costs.

RESULTS

Incremental economic costs per woman screened with VIA ranged from 4.93 US$ to 14.75 US$, and costs of cryotherapy were between 47.26 US$ and 84.48 US$ at surveyed facilities. Under base case assumptions, our model estimated the costs of VIA to be 6.12 US$ per woman and those of cryotherapy to be 27.96 US$. Sensitivity analysis showed that the number of women screened per provider and treated per facility was the most important determinants of costs. National annual programme costs were estimated to be between 0.6 and 4.0 million US$ depending on assumed coverage and adopted screening strategy.

CONCLUSION

  When choosing between different cervical cancer prevention strategies, the feasibility of increasing uptake to achieve economies of scale should be a major concern.

Health and economic impact of rotavirus vaccination in GAVI-eligible countries

BACKGROUND

Rotavirus infection is responsible for about 500,000 deaths annually, and the disease burden is disproportionately borne by children in low-income countries. Recently the World Health Organization (WHO) has released a global recommendation that all countries include infant rotavirus vaccination in their national immunization programs. Our objective was to provide information on the expected health, economic and financial consequences of rotavirus vaccines in the 72 GAVI support-eligible countries.

METHODS

We synthesized population-level data from various sources (primarily from global-level databases) for the 72 countries eligible for the support by the GAVI Alliance (GAVI-eligible countries) in order to estimate the health and economic impact associated with rotavirus vaccination programs. The primary outcome measure was incremental cost (in 2005 international dollars [I$]) per disability-adjusted life year (DALY) averted. We also projected the expected reduction in rotavirus disease burden and financial resources required associated with a variety of scale-up scenarios.

RESULTS

Under the base-case assumptions (70% coverage), vaccinating one single birth cohort would prevent about 55% of rotavirus associated deaths in the 72 GAVI-eligible countries. Assuming I$25 per vaccinated child (approximately $5 per dose), the number of countries with the incremental cost per DALY averted less than I$200 was 47. Using the WHO's cost-effectiveness threshold based on per capita GDP, the vaccines were considered cost-effective in 68 of the 72 countries (approximately 94%). A 10-year routine rotavirus vaccination would prevent 0.9-2.8 million rotavirus associated deaths among children under age 5 in the poorest parts of the world, depending on vaccine scale-up scenarios. Over the same intervention period, rotavirus vaccination programs would also prevent 4.5-13.3 million estimated cases of hospitalization and 41-107 million cases of outpatient clinic visits in the same population.

CONCLUSIONS

Our findings suggest that rotavirus vaccination would be considered a worthwhile investment for improving general development as well as childhood health level in most low-income countries, with a favorable cost-effectiveness profile even under a vaccine price ($1.5-$5.0 per dose) higher than those of traditional childhood vaccines.

Current prophylactic HPV vaccines and gynecologic premalignancies

PURPOSE OF REVIEW

Studies of the human papillomavirus (HPV) vaccines, Cervarix and Gardasil provide strong evidence for the recommendation that HPV vaccines may minimize the incidence of cervical cancer over time.

RECENT FINDINGS

Both Cervarix and Gardasil provided more than 90% efficacy in preventing cervical intraepithelial neoplasia grade 2+ (CIN 2+) disease caused by HPV 16 and 18 in women 16-26 years who were seronegative and PCR-negative for HPV 16 and 18 at baseline. Cervarix provides more than 75% efficacy in independent cross-protection against persistent HPV 31 and 45, and 47% efficacy against HPV 33; whereas Gardasil offers 50% efficacy only against persistent HPV 31. A reduction in excisional therapies for CIN 2+ is nearly 70% for Cervarix, and 40% for Gardasil. Cervarix efficacy is documented to 6.4 years; Gardasil's to 5 years. Immunologically, Cervarix induces three to nine-fold higher peak-neutralizing antibody titers to HPV 16/18 than Gardasil, has significantly higher cervicovaginal mucus-neutralizing antibody presence than Gardasil, and significantly higher B memory cell response than Gardasil. Safety reports indicate injection site reactions for both Cervarix and Gardasil. Rare serious adverse events have been reported.

Prevalence and risk profile of cervical Human papillomavirus infection in Zhejiang Province, southeast China: a population-based study

Background

Benign or malignant lesions caused by Human papillomavirus (HPV) produce considerable health burden worldwide. Since limited cross-protection would be offered between HPV types, heterogeneity in HPV type-specific distribution should be taken into account when predicting the effect of current prophylactic vaccines and forming the basic for the second-generation vaccines targeted to specific regions. Here, we investigated the prevalence of cervical HPV infection, as well as predictors concerned, in Zhejiang Province, southeast China.

Results

Totally 4987 cervical samples from five randomly chosen counties in Zhejiang Province were detected. The overall HPV prevalence was 13.3%. Established high-risk (HR) HPV prevalence was 10.2%. HPV-52 was the most prevalent type (3.1%), followed by HPV-16 (2.5%), -58 (2.1%), -68 (1.0%) and -81 (0.9%). HPV-16 or -18 were present in 3.1% of the detected samples, while 174 specimens (3.5%) were positive for any of HPV-6, -11, -16 and -18. The prevalence of HPV vaccine types was consistently low across age groups. Bimodal age distribution in HR-HPV, including established HR and probably HR-HPV, was observed, with a clear second peak in perimenopausal women. Multivariate unconditional logistic regression models revealed that partner's lifetime number of partners was the only common independent predictor of overall, established HR, established low-risk, single-type and multiple-type HPV infection in current study.

Conclusions

We have observed low prevalence of HPV vaccine types and relatively high prevalence of HPV-52 and -58 in our population. Our findings support universal "catch-up" vaccination of sexual experienced young women in Zhejiang Province, as well as enhance the hypothesis that the second-generation HPV prophylactic vaccines including HPV-52 and -58 may offer higher protection for women in China and other Asian areas. Furthermore, our data support close surveillance of perimenopausal women with HR-HPV infection.

Currently approved prophylactic HPV vaccines

Cervarix and Gardasil are two prophylactic HPV vaccines designed primarily for cervical cancer prevention. Cervarix is effective against HPV-16, -18, -31, -33 and -45, the five most common cancer-causing types, including most causes of adenocarcinoma for which we cannot screen adequately. Gardasil is effective against HPV-16, 18 and 31, three common squamous cell cancer-causing types. In addition, Gardasil is effective against HPV-6 and -11, causes of genital warts and respiratory papillomatosis. The most important determinant of vaccine impact to reduce cervical cancer is its duration of efficacy. To date, Cervarix's efficacy is proven for 6.4 years and Gardasil's for 5 years.

Challenges in treating malignancies in HIV in Nigeria

PURPOSE OF REVIEW

Sub-Saharan Africa has the largest population of people living with AIDS in the world, with Nigeria having the third largest after South Africa and India. With the advent of treatment programs, more people in Nigeria are now living with the virus but are at increased risk of cancer similar to the experience in other parts of the world. This review uses publications on HIV-associated cancers emanating from Nigeria in 2008 to map the current landscape of prevention, diagnosis and treatment of these conditions. The opportunities and challenges identified in this review will provide a template for designing appropriate clinical and public health intervention to stem another epidemic, this time of AIDS-associated malignancies.

RECENT FINDINGS

There is a paucity of literature on AIDS-associated cancers from Nigeria, and most reports are based on hospital or pathology case series. Poor case identification and diagnosis and rudimentary cancer registration militate against adequate quantification of the prevalence of AIDS-associated cancers in Nigeria. Several initiatives, working with the HIV treatment programs, governmental and nongovernmental local and international agencies, are rising to the challenge and creating new opportunities for cancer prevention, treatment and research that takes advantage of improved treatment infrastructure provided for people living with HIV/AIDS.

SUMMARY

Nigeria is about to witness substantial increase in the background incidence of cancers due to high prevalence of HIV and expanded treatment programs. Creative methods are needed to deploy effective prevention, case identification, registration and treatment programs that are consistent with the socioeconomic development of the country.

A brief history of economic evaluation for human papillomavirus vaccination policy

Background: This commentary discusses key issues for health economic evaluation and modelling, applied to human papillomavirus (HPV) vaccine programs. Methods: We outline some of the specific features of HPV disease and vaccination, and associated policy questions in light of a literature search for economic evaluations on HPV vaccination. Results: We observe that some policy questions could not be reliably addressed by many of the 43 published economic evaluations we found. Despite this, policy making on universal HPV vaccination followed shortly after vaccine licensure in many developed countries, so the role economic evaluation played in informing these decisions (pre-dating 2008) seems to have been fairly limited. For more recent decisions, however, economic evaluation is likely to have been used more widely and more intensively. Conclusions: We expect future cost-effectiveness analyses to be more instrumental in policy making regarding vaccines covering more HPV types, therapeutic HPV vaccines, and novel diagnostic tests for biomarkers of HPV infection and disease integrated with cervical screening programs.

The state of health economic evaluation research in Nigeria: a systematic review

This study assessed the state of health economic evaluation (including pharmacoeconomic) research in Nigeria. A literature search was conducted to identify health economic articles pertaining to Nigeria. Two reviewers independently scored each article in the final sample using a data collection form designed for the study. A total of 44 studies investigating a wide variety of diseases were included in the review. These articles were published in 34 different journals, mostly based outside of Nigeria, between 1988 and 2009. On average, each article was written by four authors. Most first authors had medical/clinical affiliations and resided in Nigeria at the time of publication of the study. Based on a 1 to 10 scale, with 10 indicating the highest quality, the mean quality score for all studies was 7.29 (SD 1.21) and 59% of the articles were of fair quality (score 5-7); 5% were of even lower quality. The quality of articles was statistically significantly (p < or = 0.05) related to the country of residence of the primary author (non-Nigeria = higher), country of the journal (non-Nigeria = higher), primary objective of the study (economic analysis = higher) and type of economic analysis conducted (economic evaluations higher than cost studies). The conduct of health economic (including pharmacoeconomic) research in Nigeria was limited and about two-thirds of published articles were of sub-optimal quality. More and better quality health economic research in Nigeria is warranted.

The potential cost-effectiveness of adding a human papillomavirus vaccine to the cervical cancer screening programme in South Africa

This study was designed to answer the question of whether a cervical cancer prevention programme that incorporates a human papillomavirus (HPV) vaccine is potentially more cost-effective than the current strategy of screening alone in South Africa. We developed a static Markov state transition model to describe the screening and management of cervical cancer within the South African context. The incremental cost-effectiveness ratio of adding HPV vaccination to the screening programme ranged from US $1078 to 1460 per quality-adjusted life year (QALY) gained and US$3320-4495 per life year saved, mainly depending on whether the study was viewed from a health service or a societal perspective. Using discounted costs and benefits, the threshold analysis indicated that a vaccine price reduction of 60% or more would make the vaccine plus screening strategy more cost-effective than the screening only approach. To address the issue of affordability and cost-effectiveness, the pharmaceutical companies need to make a commitment to price reductions.

Epidemiology and risk factors for human papillomavirus infection in a diverse sample of low-income young women

BACKGROUND

Two HPV vaccines prevent infection with HPV-16 and HPV-18, high-risk (cancer-associated) HPV types which together cause approximately 70% of cervical cancers; one vaccine also prevents HPV-6 and HPV-11, which together cause approximately 90% of anogenital warts. Defining type-specific HPV epidemiology in sexually experienced women will help estimate the potential clinical benefits of vaccinating this population.

OBJECTIVES

To examine HPV epidemiology in a diverse sample of sexually experienced women, and to determine factors associated with high-risk HPV and vaccine-type HPV (HPV-6, HPV-11, HPV-16 and HPV-18).

STUDY DESIGN

Cross-sectional study of 13-26-year-old women (N=409) who completed a questionnaire and provided a cervicovaginal swab. Swabs were genotyped for HPV using PCR amplification. Logistic regression models were used to determine whether participant characteristics, knowledge, and behaviors were associated with high-risk and vaccine-type HPV.

RESULTS

Most women (68.4%) were positive for >or=1 HPV type, 59.5% were positive for >or=1 high-risk type, 33.1% were positive for >or=1 vaccine-type HPV, and 3.5% were positive for both HPV-16 and HPV-18: none was positive for all four vaccine types. In adjusted logistic regression models, Black race (OR 2.03, 95% CI 1.21-3.41) and lifetime number of male sexual partners (OR 4.79, 95% CI 2.04-11.23 for >or=10 partner vs. <or=1 partner) were independently associated with high-risk HPV infection.

CONCLUSIONS

HPV prevalence was very high in this sample of sexually active young women, but <5% were positive for both HPV-16 and HPV-18, suggesting that vaccination could be beneficial for many individual women who are sexually experienced.

Benefits, cost requirements and cost-effectiveness of the HPV16,18 vaccine for cervical cancer prevention in developing countries: policy implications

Approximately 70% of cases of cervical cancer worldwide are caused by genotypes 16 and 18 of human papillomavirus (HPV), which is sexually transmitted. With the availability of an effective vaccine against these HPV types, there is real hope for reducing the global burden of cervical cancer in developing countries. Stakeholders faced with decisions about where to invest money to improve health must consider the burden of disease caused by cervical cancer relative to other priorities and the comparative benefits of different interventions. We conducted a series of analyses to obtain information for agencies drafting immunisation policy recommendations, financing coordination mechanisms, and country decision-makers on the benefits, cost requirements and cost-effectiveness of the HPV16,18 vaccine. We found that making an HPV16,18 vaccine accessible to 70% of young adolescent girls in 72 of the poorest countries, China, Thailand, and all of Latin America and the Caribbean, could prevent the future deaths of more than four million women vaccinated over the next decade. Provided the cost per vaccinated girl is less than $10-$25, adolescent HPV16,18 vaccination would be cost-effective even in relatively poor countries. Concerns about financial costs and affordability highlight the need for lowering vaccine prices, cost-efficient mechanisms for delivery of vaccinations to adolescents, and creative sources of financing.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

DISCUSSION

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

CONCLUSIONS

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

Mathematical models of cervical cancer prevention in the Asia Pacific region

Using population-based and epidemiologic data for 25 countries in Asia (22 GAVI-Alliance eligible countries, Thailand, China and Japan), a model-based approach was used to estimate averted cervical cancer cases and deaths, disability-adjusted life years (DALYs) and incremental cost-effectiveness ratios (I$/DALY averted) for vaccination of young adolescent girls against human papillomavirus (HPV) types 16 and 18. Absolute reduction in lifetime cancer risk varied between countries, depending on incidence, proportion attributable to HPV-16 and -18, and population age-structure; for example, with 70% coverage, cancer reduction was 57% in Indonesia, whereas in Cambodia, it was 49%. Screening of women over age 30 three times per lifetime, after vaccinating them as pre-adolescents, is expected to provide an additional 20% to 30% mortality reduction. Of the 22 GAVI-Alliance eligible countries, India, Bangladesh, Vietnam and Indonesia account for 87% of the total DALYs averted. Assuming a cost per vaccinated girl of I$10 ($2 per dose), the cost per DALY averted is less than I$250 in 18 of 22 countries. Assuming a cost per vaccinated girl of I$25, the cost per DALY averted is I$1,360 in China compared with I$250 in Thailand, reflecting the greater number of girls that need to be vaccinated to prevent a death from cervical cancer in China. Vaccine price has an even greater effect on predicted affordability. For the 22 GAVI Alliance-eligible countries, vaccinating 5 consecutive birth cohorts at 70% coverage would cost over US $500 million versus almost US $1.3 billion at per dose costs of $2 and $5, respectively. Including China and Thailand would add US $251 million to US $1.4 billion at per dose prices of $2 and $12.25, respectively. In the countries we assessed, vaccination of young adolescent girls against HPV-16 and -18 could be very cost-effective if the cost per vaccinated girl is less than I$10-I$25; for it to be affordable, however, even with financing assistance, vaccine prices may need to be even lower.

Human Papillomavirus Vaccines and Vaccine Implementation

Countries are now challenged by the rapid development of vaccines aimined at the primary prevention of infections. In the years to come, several vaccines will need to be considered as potential candidates in routine immunization programs. Recently, two new vaccines against two/four types of human papillomavirus (HPV) have been commercialized. Bivalent HPV 16 and 18 (Cervarix™) and quadrivalent HPV 6, 11, 16 and 18 (Gardasil®) vaccines are now extensively used in some countries. These vaccines will prevent infection and long-running complications, such as cervical cancer, other HPV-related cancers and genital warts (for the quadrivalent vaccine). The beneficial effect of these vaccines will be largely observed in women. This article summarizes the burden of HPV preventable disease worldwide and briefly describes the impact of secondary prevention and the most relevant aspects of the current available vaccines, their efficacy and safety. Finally, some major aspects that are likely to impact the introduction of these vaccines around the world are outlined, with particular emphasis on developing countries.

Health and economic impact of HPV 16 and 18 vaccination and cervical cancer screening in India

Cervical cancer is a leading cause of cancer death among women in low-income countries, with approximately 25% of cases worldwide occurring in India. We estimated the potential health and economic impact of different cervical cancer prevention strategies. After empirically calibrating a cervical cancer model to country-specific epidemiologic data, we projected cancer incidence, life expectancy, and lifetime costs (I$2005), and calculated incremental cost-effectiveness ratios (I$/YLS) for the following strategies: pre-adolescent vaccination of girls before age 12, screening of women over age 30, and combined vaccination and screening. Screening differed by test (cytology, visual inspection, HPV DNA testing), number of clinical visits (1, 2 or 3), frequency (1 x , 2 x , 3 x per lifetime), and age range (35-45). Vaccine efficacy, coverage, and costs were varied in sensitivity analyses. Assuming 70% coverage, mean reduction in lifetime cancer risk was 44% (range, 28-57%) with HPV 16,18 vaccination alone, and 21-33% with screening three times per lifetime. Combining vaccination and screening three times per lifetime provided a mean reduction of 56% (vaccination plus 3-visit conventional cytology) to 63% (vaccination plus 2-visit HPV DNA testing). At a cost per vaccinated girl of I$10 (per dose cost of $2), pre-adolescent vaccination followed by screening three times per lifetime using either VIA or HPV DNA testing, would be considered cost-effective using the country's per capita gross domestic product (I$3452) as a threshold. In India, if high coverage of pre-adolescent girls with a low-cost HPV vaccine that provides long-term protection is achievable, vaccination followed by screening three times per lifetime is expected to reduce cancer deaths by half, and be cost-effective.