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

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.

Cervical Cancer Screening in Average-Risk Women: Best Practice Advice From the Clinical Guidelines Committee of the American College of Physicians

DESCRIPTION

The purpose of this best practice advice article is to describe the indications for screening for cervical cancer in asymptomatic, average-risk women aged 21 years or older.

METHODS

The evidence reviewed in this work is a distillation of relevant publications (including systematic reviews) used to support current guidelines.

BEST PRACTICE ADVICE 1

Clinicians should not screen average-risk women younger than 21 years for cervical cancer.

BEST PRACTICE ADVICE 2

Clinicians should start screening average-risk women for cervical cancer at age 21 years once every 3 years with cytology (cytologic tests without human papillomavirus [HPV] tests).

BEST PRACTICE ADVICE 3

Clinicians should not screen average-risk women for cervical cancer with cytology more often than once every 3 years.

BEST PRACTICE ADVICE 4

Clinicians may use a combination of cytology and HPV testing once every 5 years in average-risk women aged 30 years or older who prefer screening less often than every 3 years.

BEST PRACTICE ADVICE 5

Clinicians should not perform HPV testing in average-risk women younger than 30 years.

BEST PRACTICE ADVICE 6

Clinicians should stop screening average-risk women older than 65 years for cervical cancer if they have had 3 consecutive negative cytology results or 2 consecutive negative cytology plus HPV test results within 10 years, with the most recent test performed within 5 years.

BEST PRACTICE ADVICE 7

Clinicians should not screen average-risk women of any age for cervical cancer if they have had a hysterectomy with removal of the cervix.

Systematic review of model-based cervical screening evaluations

BACKGROUND

Optimising population-based cervical screening policies is becoming more complex due to the expanding range of screening technologies available and the interplay with vaccine-induced changes in epidemiology. Mathematical models are increasingly being applied to assess the impact of cervical cancer screening strategies.

METHODS

We systematically reviewed MEDLINE®, Embase, Web of Science®, EconLit, Health Economic Evaluation Database, and The Cochrane Library databases in order to identify the mathematical models of human papillomavirus (HPV) infection and cervical cancer progression used to assess the effectiveness and/or cost-effectiveness of cervical cancer screening strategies. Key model features and conclusions relevant to decision-making were extracted.

RESULTS

We found 153 articles meeting our eligibility criteria published up to May 2013. Most studies (72/153) evaluated the introduction of a new screening technology, with particular focus on the comparison of HPV DNA testing and cytology (n = 58). Twenty-eight in forty of these analyses supported HPV DNA primary screening implementation. A few studies analysed more recent technologies - rapid HPV DNA testing (n = 3), HPV DNA self-sampling (n = 4), and genotyping (n = 1) - and were also supportive of their introduction. However, no study was found on emerging molecular markers and their potential utility in future screening programmes. Most evaluations (113/153) were based on models simulating aggregate groups of women at risk of cervical cancer over time without accounting for HPV infection transmission. Calibration to country-specific outcome data is becoming more common, but has not yet become standard practice.

CONCLUSIONS

Models of cervical screening are increasingly used, and allow extrapolation of trial data to project the population-level health and economic impact of different screening policy. However, post-vaccination analyses have rarely incorporated transmission dynamics. Model calibration to country-specific data is increasingly common in recent studies.

Trends in head and neck cancers in England from 1995 to 2011 and projections up to 2025

BACKGROUND

The magnitude of the growing burden of oropharyngeal cancers (OPC), a sub-set of head and neck cancers (HNC), is unknown in England.

METHODS

Data were extracted from population-based cancer registries in England. The burden of HNC overall and by anatomic site was described from 1995 to 2011. Projections of future rates up to 2025 were estimated using flexible age-period-cohort modelling.

RESULTS

HNC increased by 59% between 1995 and 2011 in England. Projections indicate that the number of HNC cases will increase by 55% from 2011, totalling 11,748 new cases in 2025, ranking HNC as the sixth most common cancer. Of the anatomic sites, OPC is projected to account for 35% of HNC with the largest rate increase (annual percentage change, +7.3% for men and +6.2% for women between 2011 and 2025), predominantly affecting males <60years. This projected burden is equivalent to a 239% increase in number of OPC cases. Incidence of the oral cavity, salivary glands and palate are projected to rise at lower rates, whereas rates of the nasopharynx, hypopharynx and larynx remain relatively stable or decreasing.

CONCLUSION

The substantial recent and predicted future significant increase in OPC highlights the need for prioritising the provision of cancer services for the considerable burden of OPC patients and survivors and cancer control strategies.

The next steps in cervical screening

Cervical cancer is fourth most common cancer among women with four-fifths of the global burden in low- and middle-income countries (LMICs). Persistent infection with one of the high-risk types of human papillomaviruses (HPV), particularly HPV 16/18, is the central cause of cervical neoplasia. Progress in developing feasible, alternative screening methods in LMICs and HPV vaccines have further improved cervical cancer prevention prospects. While existing screening programs in high-income countries should be re-organized, in view of the downstream effects of national HPV vaccination programs, LMICs should introduce national programs to vaccinate single year cohorts of girls aged 9-13 years with two or three doses and screen 30-35-year-old women with HPV testing to pragmatically decrease their high disease burden.

Cost effectiveness of human papillomavirus-16/18 genotyping in cervical cancer screening

BACKGROUND

There is limited understanding of the health economic implications of cervical screening with human papillomavirus (HPV)-16/18 genotyping.

OBJECTIVE

The aim of this study was to evaluate the cost effectiveness of cervical cancer primary screening with a HPV-16/18 genotyping test which simultaneously detects 12 other high-risk HPV types.

METHODS

A Markov cohort model compared four strategies: (1) cytology with reflex HPV testing for atypical squamous cells of undetermined significance (ASC-US); (2) co-testing with cytology and HPV testing; (3) HPV with reflex to cytology; and (4) HPV with 16/18 genotyping and reflex cytology (ASC-US threshold). Screening began at age 30 and was performed triennially over 40 years. Screening sensitivity and specificity values for cervical intraepithelial neoplasia (CIN) 3 were obtained from the Addressing THE Need for Advanced HPV Diagnostics (ATHENA) trial. Outcomes for a 1-year follow-up scenario wherein persistent disease was detected were estimated. Screening and cancer treatment costs were calculated from a US payer's perspective in 2013. Costs and quality-adjusted life-years (QALYs) were discounted at 3 % annually.

RESULTS

Applying a US$50,000/QALY threshold, strategy (4) dominated strategies (2) and (3) by reducing costs and cancer incidence and improving QALYs, and was cost effective versus strategy (1). Accounting for persistent ≥CIN 3 at 1 year, strategy (4) was cost effective versus all other strategies. Detecting HPV-16/18 resulted in earlier diagnosis of clinically relevant ≥CIN 3 at initial screening and efficient use of follow-up resources. Outcomes were most influenced by strategy performance.

CONCLUSIONS

Incorporating HPV-16/18 genotyping is cost effective and may improve detection of CIN, thereby preventing cervical cancer.

A survey of population-based utility scores for cervical cancer prevention

Background

With human papillomavirus (HPV) vaccination introduced in a number of countries, there is considerable interest in evaluating the cost-effectiveness of HPV testing as the primary cervical screening test in these settings. However, the availability of utility scores for these newer interventions is limited. Our aim in this paper is to present utility scores for HPV vaccination, HPV testing and cytology based screening states among women targeted for cervical screening.

Methods

We invited a random sample of women targeted for cervical screening (aged 20-69 years) living in Sydney, Australia, to participate in a face-to-face interview. Participants were asked to indicate preferences (rank and utility scores) for 10 hypothetical health states relating to HPV vaccination, cytology and primary HPV screening, cervical precursor disease and early stage cervical cancer. Preferences for hypothetical health states were measured through ranking then a two-stage standard gamble. Each participant’s own health state was measured as a utility score using the EQ5D. Potential differences by age were assessed using the Wilcox Rank Sum test.

Results

A maximum of 276 women were contacted, of which 43 (mean age 49 years) agreed to be interviewed (15.6%). The overall health state of women as measured by the EQ5D was 0.86 (95% CI: 0.83-0.89). Of the 10 health states, the highest ranked were ‘normal cytology’ and ‘HPV vaccination’ (equal 1^st). States involving an HPV positive result with a subsequent normal cytology or colposcopy were ranked below those for low grade cytological abnormalities with or without a subsequent colposcopic normal result (ranks 3-4 vs. 4-5). However, mean utility scores were broadly similar for all health states, except cervical cancer. No significant differences in scores were identified between age groups.

Conclusion

Our survey suggests health states relating to HPV testing are ranked below ‘low grade cytology’ disease abnormalities. However, this difference was minimal on the utility scale, as most values for health states were largely clustered. These results provide a preliminary set of non-clinic population-based utilities that may be used with other values to explore the economic implications of introducing HPV testing as a primary screening tool in the context of HPV vaccination.

Electronic supplementary material

The online version of this article (doi:10.1186/1756-0500-7-899) contains supplementary material, which is available to authorized users.

Human papillomavirus vaccines: key factors in planning cost-effective vaccination programs

Prophylactic HPV vaccines hold tremendous potential for reducing cervical and non-cervical HPV-related disease burden worldwide. To maximize on this potential, policy officials will need to carefully consider available evidence, existing uncertainties and the cost-effectiveness of mass HPV vaccination programs in the context of their respective nations and/or regions. Proper harmonization of primary prevention strategies with secondary prevention efforts will also be important. Decisions following such considerations may ultimately depend on programmatic objectives, infrastructure and available resources. Continued research and surveillance surrounding HPV vaccination will be essential for filling current knowledge gaps, and forcing ongoing reconsiderations of selected immunization strategies.

Development of a quality framework for models of cervical screening and its application to evaluations of the cost-effectiveness of HPV vaccination in developed countries

BACKGROUND

HPV vaccination has now been introduced in most developed countries, but this has occurred in the context of established cervical cancer screening mechanisms which provide population-level protection against the most common HPV-related cancer. Therefore, estimating the cost-effectiveness of HPV vaccination to further reduce HPV-related disease depends in large part on the estimation of the effectiveness of the cervical screening 'background'. The aim of this study was to systematically review and assess methods for simulating cervical screening in decision analytic models used for evaluation of HPV vaccination.

METHODS

Existing quality frameworks for economic models were extended to develop a specific quality framework for models of cervical screening. This involved domains for model structure, parameterisation (data sources) and validation (consistency). A systematic review of economic evaluations of HPV vaccination was then conducted, and assessment of cervical screening model components was then performed via application of the new quality framework.

RESULTS

Generally, models took into account population-level cervical screening participation, but were inconsistent in their approach to modelling abnormal smear management, diagnostic evaluation and treatment of precancerous disease. There was also considerable variability in the accuracy of modelling clinical pathways and the scope of validation performed for screening-related outcomes, with focus directed towards cervical cancer targets. Only a few models comprehensively validated against observed pre-cancerous abnormalities.

CONCLUSION

Models of HPV vaccination in developed countries can be improved by further attention to the 'background' modelling of secondary protection via cervical screening. The quality framework developed for this review can be used to inform future HPV vaccination evaluations, including evaluations of the cost-effectiveness of male vaccination and next generation HPV vaccines, and to assess models used to evaluate new cervical screening technologies and recommendations.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

Incremental benefits of male HPV vaccination: accounting for inequality in population uptake

BACKGROUND

Vaccines against HPV16/18 are approved for use in females and males but most countries currently have female-only programs. Cultural and geographic factors associated with HPV vaccine uptake might also influence sexual partner choice; this might impact post-vaccination outcomes. Our aims were to examine the population-level impact of adding males to HPV vaccination programs if factors influencing vaccine uptake also influence partner choice, and additionally to quantify how this changes the post-vaccination distribution of disease between subgroups, using incident infections as the outcome measure.

METHODS

A dynamic model simulated vaccination of pre-adolescents in two scenarios: 1) vaccine uptake was correlated with factors which also affect sexual partner choice ("correlated"); 2) vaccine uptake was unrelated to these factors ("unrelated"). Coverage and degree of heterogeneity in uptake were informed by observed data from Australia and the USA. Population impact was examined via the effect on incident HPV16 infections. The rate ratio for post-vaccination incident HPV16 in the lowest compared to the highest coverage subgroup (RR(L)) was calculated to quantify between-group differences in outcomes.

RESULTS

The population-level incremental impact of adding males was lower if vaccine uptake was "correlated", however the difference in population-level impact was extremely small (<1%) in the Australia and USA scenarios, even under the conservative and extreme assumption that subgroups according to coverage did not mix at all sexually. At the subgroup level, "correlated" female-only vaccination resulted in RR(L)= 1.9 (Australia) and 1.5 (USA) in females, and RR(L)= 1.5 and 1.3 in males. "Correlated" both-sex vaccination increased RR(L) to 4.2 and 2.1 in females and 3.9 and 2.0 in males in the Australia and USA scenarios respectively.

CONCLUSIONS

The population-level incremental impact of male vaccination is unlikely to be substantially impacted by feasible levels of heterogeneity in uptake. However, these findings emphasize the continuing importance of prioritizing high coverage across all groups in HPV vaccination programs in terms of achieving equality of outcomes.

Comprehensive control of human papillomavirus infections and related diseases

Infection with human papillomavirus (HPV) is recognized as one of the major causes of infection-related cancer worldwide, as well as the causal factor in other diseases. Strong evidence for a causal etiology with HPV has been stated by the International Agency for Research on Cancer for cancers of the cervix uteri, penis, vulva, vagina, anus and oropharynx (including base of the tongue and tonsils). Of the estimated 12.7 million new cancers occurring in 2008 worldwide, 4.8% were attributable to HPV infection, with substantially higher incidence and mortality rates seen in developing versus developed countries. In recent years, we have gained tremendous knowledge about HPVs and their interactions with host cells, tissues and the immune system; have validated and implemented strategies for safe and efficacious prophylactic vaccination against HPV infections; have developed increasingly sensitive and specific molecular diagnostic tools for HPV detection for use in cervical cancer screening; and have substantially increased global awareness of HPV and its many associated diseases in women, men, and children. While these achievements exemplify the success of biomedical research in generating important public health interventions, they also generate new and daunting challenges: costs of HPV prevention and medical care, the implementation of what is technically possible, socio-political resistance to prevention opportunities, and the very wide ranges of national economic capabilities and health care systems. Gains and challenges faced in the quest for comprehensive control of HPV infection and HPV-related cancers and other disease are summarized in this review. The information presented may be viewed in terms of a reframed paradigm of prevention of cervical cancer and other HPV-related diseases that will include strategic combinations of at least four major components: 1) routine introduction of HPV vaccines to women in all countries, 2) extension and simplification of existing screening programs using HPV-based technology, 3) extension of adapted screening programs to developing populations, and 4) consideration of the broader spectrum of cancers and other diseases preventable by HPV vaccination in women, as well as in men. Despite the huge advances already achieved, there must be ongoing efforts including international advocacy to achieve widespread-optimally universal-implementation of HPV prevention strategies in both developed and developing countries. This article summarizes information from the chapters presented in a special ICO Monograph 'Comprehensive Control of HPV Infections and Related Diseases' Vaccine Volume 30, Supplement 5, 2012. Additional details on each subtopic and full information regarding the supporting literature references may be found in the original chapters.

Comprehensive control of human papillomavirus infections and related diseases

Infection with human papillomavirus (HPV) is recognized as one of the major causes of infection-related cancer worldwide, as well as the causal factor in other diseases. Strong evidence for a causal etiology with HPV has been stated by the International Agency for Research on Cancer for cancers of the cervix uteri, penis, vulva, vagina, anus and oropharynx (including base of the tongue and tonsils). Of the estimated 12.7 million new cancers occurring in 2008 worldwide, 4.8% were attributable to HPV infection, with substantially higher incidence and mortality rates seen in developing versus developed countries. In recent years, we have gained tremendous knowledge about HPVs and their interactions with host cells, tissues and the immune system; have validated and implemented strategies for safe and efficacious prophylactic vaccination against HPV infections; have developed increasingly sensitive and specific molecular diagnostic tools for HPV detection for use in cervical cancer screening; and have substantially increased global awareness of HPV and its many associated diseases in women, men, and children. While these achievements exemplify the success of biomedical research in generating important public health interventions, they also generate new and daunting challenges: costs of HPV prevention and medical care, the implementation of what is technically possible, socio-political resistance to prevention opportunities, and the very wide ranges of national economic capabilities and health care systems. Gains and challenges faced in the quest for comprehensive control of HPV infection and HPV-related cancers and other disease are summarized in this review. The information presented may be viewed in terms of a reframed paradigm of prevention of cervical cancer and other HPV-related diseases that will include strategic combinations of at least four major components: 1) routine introduction of HPV vaccines to women in all countries, 2) extension and simplification of existing screening programs using HPV-based technology, 3) extension of adapted screening programs to developing populations, and 4) consideration of the broader spectrum of cancers and other diseases preventable by HPV vaccination in women, as well as in men. Despite the huge advances already achieved, there must be ongoing efforts including international advocacy to achieve widespread-optimally universal-implementation of HPV prevention strategies in both developed and developing countries. This article summarizes information from the chapters presented in a special ICO Monograph 'Comprehensive Control of HPV Infections and Related Diseases' Vaccine Volume 30, Supplement 5, 2012. Additional details on each subtopic and full information regarding the supporting literature references may be found in the original chapters.

Too late to vaccinate? The incremental benefits and cost-effectiveness of a delayed catch-up program using the 4-valent human papillomavirus vaccine in Norway

BACKGROUND

Human papillomavirus (HPV) vaccines are ideally administered before HPV exposure; therefore, catch-up programs for girls past adolescence have not been readily funded. We evaluated the benefits and cost-effectiveness of a delayed, 1-year female catch-up vaccination program in Norway.

METHODS

We calibrated a dynamic HPV transmission model to Norwegian data and projected the costs and benefits associated with 8 HPV-related conditions while varying the upper vaccination age limit to 20, 22, 24, or 26 years. We explored the impact of vaccine protection in women with prior vaccine-targeted HPV infections, vaccine cost, coverage, and natural- and vaccine-induced immunity.

RESULTS

The incremental benefits and cost-effectiveness decreased as the upper age limit for catch-up increased. Assuming a vaccine cost of $150/dose, vaccination up to age 20 years remained below Norway's willingness-to-pay threshold (approximately $83 000/quality-adjusted life year gained); extension to age 22 years was cost-effective at a lower cost per dose ($50-$75). At high levels of vaccine protection in women with prior HPV exposure, vaccinating up to age 26 years was cost-effective. Results were stable with lower coverage.

CONCLUSIONS

HPV vaccination catch-up programs, 5 years after routine implementation, may be warranted; however, even at low vaccine cost per dose, the cost-effectiveness of vaccinating beyond age 22 years remains uncertain.

Is expanding HPV vaccination programs to include school-aged boys likely to be value-for-money: a cost-utility analysis in a country with an existing school-girl program

Background

Similar to many developed countries, vaccination against human papillomavirus (HPV) is provided only to girls in New Zealand and coverage is relatively low (47% in school-aged girls for dose 3). Some jurisdictions have already extended HPV vaccination to school-aged boys. Thus, exploration of the cost-utility of adding boys’ vaccination is relevant. We modeled the incremental health gain and costs for extending the current girls-only program to boys, intensifying the current girls-only program to achieve 73% coverage, and extension of the intensive program to boys.

Methods

A Markov macro-simulation model, which accounted for herd immunity, was developed for an annual cohort of 12-year-olds in 2011 and included the future health states of: cervical cancer, pre-cancer (CIN I to III), genital warts, and three other HPV-related cancers. In each state, health sector costs, including additional health costs from extra life, and quality-adjusted life-years (QALYs) were accumulated. The model included New Zealand data on cancer incidence and survival, and other cause mortality (all by sex, age, ethnicity and deprivation).

Results

At an assumed local willingness-to-pay threshold of US$29,600, vaccination of 12-year-old boys to achieve the current coverage for girls would not be cost-effective, at US$61,400/QALY gained (95% UI $29,700 to $112,000; OECD purchasing power parities) compared to the current girls-only program, with an assumed vaccine cost of US$59 (NZ$113). This was dominated though by the intensified girls-only program; US$17,400/QALY gained (95% UI: dominant to $46,100). Adding boys to this intensified program was also not cost-effective; US$128,000/QALY gained, 95% UI: $61,900 to $247,000).

Vaccination of boys was not found to be cost-effective, even for additional scenarios with very low vaccine or program administration costs – only when combined vaccine and administration costs were NZ$125 or lower per dose was vaccination of boys cost-effective.

Conclusions

These results suggest that adding boys to the girls-only HPV vaccination program in New Zealand is highly unlikely to be cost-effective. In order for vaccination of males to become cost-effective in New Zealand, vaccine would need to be supplied at very low prices and administration costs would need to be minimised.

Comprehensive control of human papillomavirus infections and related diseases

Infection with human papillomavirus (HPV) is recognized as one of the major causes of infection-related cancer worldwide, as well as the causal factor in other diseases. Strong evidence for a causal etiology with HPV has been stated by the International Agency for Research on Cancer for cancers of the cervix uteri, penis, vulva, vagina, anus and oropharynx (including base of the tongue and tonsils). Of the estimated 12.7 million new cancers occurring in 2008 worldwide, 4.8% were attributable to HPV infection, with substantially higher incidence and mortality rates seen in developing versus developed countries. In recent years, we have gained tremendous knowledge about HPVs and their interactions with host cells, tissues and the immune system; have validated and implemented strategies for safe and efficacious prophylactic vaccination against HPV infections; have developed increasingly sensitive and specific molecular diagnostic tools for HPV detection for use in cervical cancer screening; and have substantially increased global awareness of HPV and its many associated diseases in women, men, and children. While these achievements exemplify the success of biomedical research in generating important public health interventions, they also generate new and daunting challenges: costs of HPV prevention and medical care, the implementation of what is technically possible, socio-political resistance to prevention opportunities, and the very wide ranges of national economic capabilities and health care systems. Gains and challenges faced in the quest for comprehensive control of HPV infection and HPV-related cancers and other disease are summarized in this review. The information presented may be viewed in terms of a reframed paradigm of prevention of cervical cancer and other HPV-related diseases that will include strategic combinations of at least four major components: 1) routine introduction of HPV vaccines to women in all countries, 2) extension and simplification of existing screening programs using HPV-based technology, 3) extension of adapted screening programs to developing populations, and 4) consideration of the broader spectrum of cancers and other diseases preventable by HPV vaccination in women, as well as in men. Despite the huge advances already achieved, there must be ongoing efforts including international advocacy to achieve widespread-optimally universal-implementation of HPV prevention strategies in both developed and developing countries. This article summarizes information from the chapters presented in a special ICO Monograph 'Comprehensive Control of HPV Infections and Related Diseases' Vaccine Volume 30, Supplement 5, 2012. Additional details on each subtopic and full information regarding the supporting literature references may be found in the original chapters.

Long-term HPV type-specific risks for ASCUS and LSIL: a 14-year follow-up of a randomized primary HPV screening trial

Human papillomavirus (HPV) infections result in a significant burden of low-grade cervical lesions. Between 1997 and 2000, our randomized trial of primary HPV screening enrolled 12,527 women participating in population-based screening. Women between 32 and 38 years of age (median: 34, interquartile range: 33-37) were randomized to HPV and cytology double testing (intervention arm, n = 6,257 enrolled, n = 5,888 followed-up) or to cytology, with samples frozen for future HPV testing (control arm, n = 6,270 enrolled, n = 5,795 followed-up). We estimated the HPV type-specific, long-term absolute risks (AR), and population attributable proportions (PAR) for cytological diagnoses of atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) and for histopathologically diagnosed cervical intraepithelial neoplasia grade 1 (CIN1). The women were followed using comprehensive, nationwide register-based follow-up. During a mean follow-up time of 11.07 years, 886 ASCUS and LSIL lesions were detected, 448 in the intervention arm and 438 in the control arm. Poisson regression estimated the incidence rate ratios (IRRs) of low-grade lesions by HPV type. The IRRs were strongly dependent on follow-up time. The IRRs for ASCUS/LSIL associated with high-risk HPV positivity were 18.6 (95% CI: 14.9-23.4) during the first screening round, 4.1 (95% CI: 2.8-6.2) during the second, 2.6 (95% CI: 1.7-4.1) during the third, and 1.1 (95% CI: 0.7-1.8) for >9 years of follow-up, with similar declines seen for the individual types. Type 16 contributed consistently to the greatest proportion of ASCUS, LSIL, and CIN1 risk in the population (first screening round PAR: ASCUS: 15.5% (95% CI: 9.7-21.9), LSIL: 14.7% (95% CI: 8.0-20.9), and CIN1: 13.4% (95% CI: 3.2-22.5)), followed by type 31 [8.4% (95% CI: 4.2-12.5) for ASCUS to 17.3% (95% CI: 6.8-26.6) for CIN1]. In summary, most ASCUS/LSIL lesions associated with HPV infection are caused by new HPV infections and most lesions are found during the first screening round.

Mind the gaps: what's missing from current economic evaluations of universal HPV vaccination?

BACKGROUND

Since the original licensing of human papilloma virus (HPV) vaccination for women, evidence is accumulating of its effectiveness in preventing HPV-related conditions in men, and universal vaccination (vaccinating men and women) is now recommended in some countries. Several models of the cost-effectiveness of universal HPV vaccination have been published, but results have been mixed. This article assesses the extent to which economic studies have captured the range of values associated with universal HPV vaccination, and how this influences estimates of its cost-effectiveness.

METHODS

Eight published economic evaluations of universal HPV vaccination were reviewed to identify which of the values associated with universal HPV vaccination were included in each analysis.

RESULTS

Studies of the cost-effectiveness of universal HPV vaccination capture only a fraction of the values generated. Most studies focused on impacts on health and health system cost, and only captured these partially. A range of values is excluded from most studies, including impacts on productivity, patient time and costs, carers and family costs, and broader social values such as the right to access treatment. Further, those studies that attempted to capture these values only did so partially.

DISCUSSION

Decisions to invest in universal HPV vaccination need to be based on a complete assessment of the value that it generates. This is not provided by existing economic evaluations. Further work is required to understand this value. First, research is required to understand how HPV-related health outcomes impact on society including, for instance, their impact on productivity. Second, consideration should be given to alternative approaches to capture this broader set of values in a manner useful to decisions-makers, such as multi-criteria decision analysis.

Women have a preference for their male partner to be HPV vaccinated

Background

Peer influence and social networking can change female adolescent and young adult behavior. Peer influence on preferences for male human papillomavirus (HPV) vaccination has not been documented. The primary aim of this study was to determine if women had preferences about male sexual partner HPV vaccination receipt.

Methods and Findings

A prospective survey of women 18–26 years of age was conducted at an urban university student health clinic. Education about the two HPV vaccines, cervical cancer and genital warts was provided. Women self-reported their demographic and medical history data, as well as their own preferences for HPV vaccine and their preferences for their male partner HPV vaccine using a 5 point Likert scale. 601 women, mean age of 21.5 years (SD 2.4), participated between 2011 and 2012. Nearly 95% of respondents were heterosexual; condoms and contraceptives were used in over half of the population. Regardless of the woman's vaccination status, women had significantly higher (strongly agree/agree) preferences for the male partner being vaccinated with HPV4 than not caring if he was vaccinated (63.6% vs. 13.1%, p<0.001). This preference was repeated for sexual risk factors and past reproductive medical history. Women who received HPV4 compared to those choosing HPV2 had a significantly lower proportion of preferences for not caring if the male partner was vaccinated (13% vs. 22%, p = 0.015).

Conclusions

Women preferred a HPV vaccinated male partner. Peer messaging might change the male HPV vaccination uptake.

Mathematical modelling and prediction in infectious disease epidemiology

We discuss to what extent disease transmission models provide reliable predictions. The concept of prediction is delineated as it is understood by modellers, and illustrated by some classic and recent examples. A precondition for a model to provide valid predictions is that the assumptions underlying it correspond to the reality, but such correspondence is always limited—all models are simplifications of reality. A central tenet of the modelling enterprise is what we may call the ‘robustness thesis’: a model whose assumptions approximately correspond to reality will make predictions that are approximately valid. To examine which of the predictions made by a model are trustworthy, it is essential to examine the outcomes of different models. Thus, if a highly simplified model makes a prediction, and if the same or a very similar prediction is made by a more elaborate model that includes some mechanisms or details that the first model did not, then we gain some confidence that the prediction is robust. An important benefit derived from mathematical modelling activity is that it demands transparency and accuracy regarding our assumptions, thus enabling us to test our understanding of the disease epidemiology by comparing model results and observed patterns. Models can also assist in decision-making by making projections regarding important issues such as intervention-induced changes in the spread of disease.

Cost-effectiveness and equity impacts of three HPV vaccination programmes for school-aged girls in New Zealand

BACKGROUND

As with many high-income countries, vaccination coverage against human papilloma virus (HPV) infection is not high in New Zealand (NZ) at 47% in school-aged girls for three doses. We estimate the health gains, net-cost and cost-effectiveness of the currently implemented HPV national vaccination programme of vaccination dispersed across schools and primary care, and two alternatives: school-based only (assumed coverage as per Australia: 73%), and mandatory school-based vaccination but with opt-out permitted (coverage 93%). We also generate estimates by social group (sex, ethnic and deprivation group).

METHODS

A Markov macro-simulation model was developed for 12-year-old girls and boys in 2011, with future health states of: cervical cancer, pre-cancer (CIN I-III), genital warts, and three other HPV-related cancers (oropharyngeal, anal, vulvar cancer). In each state health sector costs, including additional health sector costs from extra life, and quality-adjusted life years (QALYs) were accumulated.

RESULTS

The current HPV vaccination programme has an estimated cost-effectiveness of NZ$18,800/QALY gained (about US$9700/QALY gained using the OECD's purchasing power parities; 95% UI: US$6900 to $33,700) compared to the status quo in NZ prior to 2008 (no vaccination, screening alone). The incremental cost-effectiveness ratio (ICER) of an intensive school-based only programme of girls, compared to the current situation, was US$33,000/QALY gained. Mandatory vaccination appeared least cost-effective (ICER compared to school-based of US$117,000/QALY gained, but with wide 95% uncertainty limits from $56,000 to $220,000). All interventions generated more QALYs per 12-year-old for Māori (indigenous population) and people living in deprived areas (range 5-25% greater QALYs gained).

INTERPRETATION

A more intensive school-only vaccination programme seems warranted. Reductions in vaccine price will greatly improve cost-effectiveness of all options, possibly making a law for mandatory vaccination optimal from a health sector perspective. All interventions could reduce ethnic and socioeconomic disparities in HPV-related disease.

Testing previous model predictions against new data on human papillomavirus vaccination program outcomes

BACKGROUND

Vaccination against human papillomavirus (HPV), predominantly targeting young females, has been introduced in many countries. Decisions to implement programs, which have involved substantial investment by governments, have in part been based on findings from cost-effectiveness models. Now that vaccination programs have been in place for some years, it is becoming possible to observe their effects, and compare these with model effectiveness predictions made previously.

FINDINGS

Australia introduced a publicly-funded HPV vaccination program in 2007. Recently reported Australian data from a repeat cross-sectional survey showed a substantial (77%) fall in HPV16 prevalence in women aged 18-24 years in 2010-2011, compared to pre-vaccination levels. We have previously published model predictions for the population-wide reduction in incident HPV16 infections post-vaccination in Australia. We compared prior predictions from the same model (including the same assumed uptake rates) for the reduction in HPV16 prevalence in women aged 18-24 years by the end of 2010 with the observed data. Based on modelled vaccine uptake which is consistent with recent data on three-dose uptake (78% at 12-13 years; lower uptake in older catch-up age cohorts), we had predicted a 70% reduction in prevalence in 18-24 year old females by the end of 2010. Based on modelled vaccine uptake consistent with recent national data for two-dose coverage and similar to that reported by women in the cross-sectional study, we had predicted a 79% reduction.

CONCLUSIONS

A close correspondence was observed between the prior model predictions and the recently reported findings on the rapid drop in HPV prevalence in Australia. Because broadly similar effectiveness predictions have been reported from other models used for cost-effectiveness predictions, this provides reassurance that the substantial public investment in HPV vaccination has been grounded in valid estimates of the effects of vaccination.

Global evidence reaffirms the case for routine HPV and potential HIV adolescent vaccination in South Africa

ABSTRACT: 

The availability of two prophylactic HPV vaccines, coupled with a potential prophylactic HIV vaccine delivered to adolescents through a school-based sexual and reproductive health platform represents a potentially significant, potent long-term primary prevention strategy against two sexually transmitted infections: HPV and HIV infection within a highly susceptible group. South Africa has earmarked the re-engineering of school health services. This initiative ensures a ‘health presence in every school’ focused on developing a social, sexual and reproductive health platform within secondary schools addressing HIV/AIDS prevention, teenage pregnancies and social concerns such as drug abuse. Despite this opportunistic platform for HIV and HPV vaccines introduction among adolescents, much work remains to overcome existing ethical and financial and programmatic barriers.

Comprehensive control of human papillomavirus infections and related diseases

Infection with human papillomavirus (HPV) is recognized as one of the major causes of infection-related cancer worldwide, as well as the causal factor in other diseases. Strong evidence for a causal etiology with HPV has been stated by the International Agency for Research on Cancer for cancers of the cervix uteri, penis, vulva, vagina, anus and oropharynx (including base of the tongue and tonsils). Of the estimated 12.7 million new cancers occurring in 2008 worldwide, 4.8% were attributable to HPV infection, with substantially higher incidence and mortality rates seen in developing versus developed countries. In recent years, we have gained tremendous knowledge about HPVs and their interactions with host cells, tissues and the immune system; have validated and implemented strategies for safe and efficacious prophylactic vaccination against HPV infections; have developed increasingly sensitive and specific molecular diagnostic tools for HPV detection for use in cervical cancer screening; and have substantially increased global awareness of HPV and its many associated diseases in women, men, and children. While these achievements exemplify the success of biomedical research in generating important public health interventions, they also generate new and daunting challenges: costs of HPV prevention and medical care, the implementation of what is technically possible, socio-political resistance to prevention opportunities, and the very wide ranges of national economic capabilities and health care systems. Gains and challenges faced in the quest for comprehensive control of HPV infection and HPV-related cancers and other disease are summarized in this review. The information presented may be viewed in terms of a reframed paradigm of prevention of cervical cancer and other HPV-related diseases that will include strategic combinations of at least four major components: 1) routine introduction of HPV vaccines to women in all countries, 2) extension and simplification of existing screening programs using HPV-based technology, 3) extension of adapted screening programs to developing populations, and 4) consideration of the broader spectrum of cancers and other diseases preventable by HPV vaccination in women, as well as in men. Despite the huge advances already achieved, there must be ongoing efforts including international advocacy to achieve widespread-optimally universal-implementation of HPV prevention strategies in both developed and developing countries. This article summarizes information from the chapters presented in a special ICO Monograph 'Comprehensive Control of HPV Infections and Related Diseases' Vaccine Volume 30, Supplement 5, 2012. Additional details on each subtopic and full information regarding the supporting literature references may be found in the original chapters.