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

Estimating the Long-Term Clinical Impact of Cervical Cancer Vaccination in Taiwan

The high burden of human papillomavirus (HPV) infection and subsequent cervical cancer in the presence of screening in Taiwan suggests the need for further prevention strategies. Epidemiology and screening practices vary considerably between countries, and specific analyses are required to estimate the impact of HPV vaccination. This study adapted a computer-based health economic model to Taiwan to project the clinical impact of the introduction of a prophylactic vaccine against persistent HPV 16/18 infection on cervical disease. A Markov model based on the natural history of HPV and cervical cancer was developed to simulate transitions between health states (normal, HPV, cervical intraepithelial neoplasia [CIN] stages I to III, cervical cancer stages I to IV, and death) in the presence of screening. The model was calibrated to Taiwan epidemiological end points including age-specific HPV prevalence, prevalence of CIN lesions, and predicted cervical cancer incidence and mortality. Taiwanese screening and treatment practices were modeled, and published clinical trial data were used to estimate vaccine efficacy. With 100% vaccine coverage in a 13-year-old cohort of females, there is estimated to be a 71% reduction in cervical cancer cases and deaths due to all HPV types and substantial reductions in the prevalence of precancerous lesions and screening outcomes. Removing the risk of HPV infection of a large proportion of Taiwanese females, with a high underlying cervical cancer incidence rate, would be expected to have dramatic effects on the health care system and mortality in Taiwan.

Cost effectiveness of herpes zoster vaccine in Canada

BACKGROUND

Herpes zoster (HZ), or shingles, results from reactivation of latent varicella zoster virus in the sensory ganglia of adults, and results in significant morbidity in the elderly, including the development of post-herpetic neuralgia (PHN). The lifetime risk of HZ is about 20-30% and the incidence increases with age. The protective effect of the HZ vaccine has been shown in a large clinical trial; however, the effectiveness of the vaccine decreased with age of vaccination.

OBJECTIVE

We sought to compare the incremental cost and health benefits of HZ vaccine over status quo (no HZ vaccine) from the perspective of the Canadian healthcare payer.

METHODS

We developed a discrete-event simulation model comparing the costs and QALYs accrued to patients receiving HZ vaccine to those who did not. The effect of the vaccine on the (i) incidence of severe, moderate or mild HZ; (ii) severity and duration of HZ; (iii) incidence of PHN among patients with HZ; (iv) duration of PHN; and (v) costs associated with treating HZ and PHN were modelled. Data from published literature, including the Shingle Prevention Study, were used for transition probabilities. Health resource utilizations were estimated using administrative data retrieved from the British Columbia Medical Services Plan and hospital separation databases in British Columbia from 1994 to 2003. Utility estimates were obtained from various published sources. Canadian 2008 costs were used and both cost and QALYs were discounted at a 5% annual rate in the base-case analyses.

RESULTS

On average, receiving the vaccination lowered mean direct medical costs (excluding the vaccine costs) by $Can35 per person. The incremental cost and QALYs per person receiving the vaccine versus no vaccination were $Can115 and 0.0028 QALYs, respectively, resulting in an incremental cost-effectiveness ratio of $Can41 709 per QALY gained for a cohort of elderly subjects aged >or=60 years. Results were robust in probabilistic and univariate sensitivity analyses. Expected value of perfect information was estimated at $Can47.72 per person, reflecting the expected monetary losses that could be avoided by having perfect information on all model parameters.

CONCLUSION

HZ vaccination of adults, especially for individuals aged 60-75 years, seems to be a cost-effective intervention and might be considered by Canadian decision makers.

Cost-effectiveness evaluation of a quadrivalent human papillomavirus vaccine in Belgium

BACKGROUND

The introduction of a quadrivalent human papillomavirus (HPV; types 6, 11, 16, 18) vaccine is expected to significantly reduce the burden of cervical cancer, cervical intraepithelial neoplasia (CIN), genital warts and other HPV-related diseases.

OBJECTIVE

To determine the cost effectiveness of providing a quadrivalent (6,11,16,18) HPV vaccine programme in adolescent females aged 12 years in addition to the existing cervical cancer screening programme in Belgium.

METHODS

A Markov state-transition model was developed for the Belgian context in order to evaluate the long-term impact of vaccinating a cohort of girls aged 12 years alongside the existing screening programme. Women were followed until the age of 85 years. A vaccine that would prevent 100% of diseases associated with HPV-6, -11, -16 and -18, with lifetime duration of efficacy, 80% coverage, in conjunction with current screening, was compared with screening alone. For this analysis, 35% of cases of CIN-1, 55% of CIN-2/3, 75% of cervical cancer and 90% of genital warts were considered to be attributable to HPV-6, -11, -16 or -18. The model estimated lifetime risks and total lifetime healthcare costs, survival and QALYs for cervical cancer, CIN and genital warts. Outcomes validation was applied. Model outcomes also included incremental costs per life-year gained and incremental costs per QALY gained. The analysis was conducted from the perspective of the Belgian healthcare payer, and costs were in year 2006 values.

RESULTS

The model estimated a reduction in the lifetime risk of cervical cancer from 0.94% to 0.34%, therefore preventing 362 cases of cervical cancer and 131 related deaths in a cohort of 60,000 girls aged 12 years in Belgium. The base-case scenario suggests quadrivalent HPV vaccination in addition to current cervical screening in Belgium to be cost effective at euro 10,546 per QALY. This is within the accepted range of cost-effective interventions in Europe. This cost effectiveness is maintained for different parameter assumptions in the sensitivity analysis, with the exception of very high discount rates for costs and medical benefits, but, even in the worst case, ratios were still less than euro 50,000 per QALY. Even when a separate scenario modelled the requirement for a booster vaccination to sustain a lifetime duration of protection, the results remained cost effective at eruo 17,388 per QALY.

CONCLUSIONS

Vaccination with a quadrivalent HPV vaccine appears to be a cost-effective public health intervention in conjunction with the existing screening programme in Belgium. The additional costs of introducing vaccination to the established screening programme would be offset by the potential savings from not having to treat the diseases caused by HPV-6, -11, -16 or -18.

Effectiveness and cost effectiveness of human papillomavirus vaccine: a systematic review

The recent approval of human papillomavirus (HPV) vaccine means that decision makers need information beyond that available from randomized clinical trials to recommend funding for this vaccination programme. Modelling and economic studies have addressed some of those information needs. We conducted a qualitative systematic review to summarize the existing data. Review articles were obtained from an extensive literature search on studies using mathematical modelling (either a Markov or transmission dynamic model) to determine the effectiveness or cost effectiveness of an HPV vaccine compared with the current cytology-based Pap smear screening programme. A total of 21 studies (but 22 models) were included in the review after being assessed for methodological quality. All of the included studies had used a mathematical model to determine the effectiveness of an HPV vaccine, whilst 13 had also conducted a cost-effectiveness analysis. Although the studies used different model structures, baseline parameters and assumptions, all studies showed that vaccination would decrease rates of HPV infection, precancerous lesions and cervical cancer. Studies had a consistent message with respect to cost effectiveness: a female-only vaccination programme is cost effective compared with the current cytology-based Pap smear screening programme, while the cost effectiveness of a male and female vaccination programme is generally not cost effective compared with female-only vaccination.

Funding of drugs: do vaccines warrant a different approach?

Vaccines have features that require special consideration when assessing their cost-effectiveness. These features are related to herd immunity, quality-of-life losses in young children, parental care and work loss, time preference, uncertainty, eradication, macroeconomics, and tiered pricing. Advisory committees on public funding for vaccines, or for pharmaceuticals in general, should be knowledgable about these special features. We discuss key issues and difficulties in decision making for vaccines against rotavirus, human papillomavirus, varicella-zoster virus, influenza virus, and Streptococcus pneumoniae. We argue that guidelines for economic evaluation should be reconsidered generally to recommend (1) modelling options for the assessment of interventions against infectious diseases; (2) a wider perspective to account for impacts on third parties, if relevant; (3) a wider scope of costs than health-care system costs alone, if appropriate; and (4) alternative discounting techniques to explore social time preference over long periods.

Modeling cervical cancer prevention in developed countries

Cytology-based screening has reduced cervical cancer mortality in countries able to implement, sustain and financially support organized programs that achieve broad coverage. These ongoing secondary prevention efforts considerably complicate the question of whether vaccination against human papillomavirus (HPV) types 16 and 18 should be introduced. Policy questions focus primarily on the target ages of vaccination, appropriate ages for a temporary "catch-up" program, possible revisions in screening policies to optimize synergies with vaccination, including the increased used of HPV DNA testing, and the inclusion of boys in the vaccination program. Decision-analytic models are increasingly being developed to simulate disease burden and interventions in different settings in order to evaluate the benefits and cost-effectiveness of primary and secondary interventions for informed decision-making. This article is a focused review on existing mathematical models that have been used to evaluate HPV vaccination in the context of developed countries with existing screening programs. Despite variations in model assumptions and uncertainty in existing data, pre-adolescent vaccination of girls has been consistently found to be attractive in the context of current screening practices, provided there is complete and lifelong vaccine protection and widespread vaccination coverage. Questions related to catch-up vaccination programs, potential benefits of other non-cervical cancer outcomes and inclusion of boys are subject to far more uncertainty, and results from these analyses have reached conflicting conclusions. Most analyses find that some catch-up vaccination is warranted but becomes increasingly unattractive as the catch-up age is extended, and vaccination of boys is unlikely to be cost-effective if reasonable levels of coverage are achieved in girls or coverage among girls can be improved. The objective of this review is to highlight points of consensus and qualitative themes, to discuss the areas of divergent findings, and to provide insight into critical decisions related to cervical cancer prevention.

Health and economic impact associated with a quadrivalent HPV vaccine in Italy

OBJECTIVE

The aim of this study was to determine the health impact and cost-effectiveness of introducing a human papillomavirus (HPV) vaccination programme with a quadrivalent vaccine alongside the existing cervical cancer screening programme in comparison to the current context in Italy.

METHODS

A US Markov model was adapted to the Italian context, assuming under base case 80% vaccine coverage rate, lifetime duration of protection in a cohort of girls aged 12 years and discount rates of 1.5% and 3% for health benefits and costs, respectively, and estimating direct medical costs.

RESULTS

The HPV vaccination in association with the current screening programme would allow to avoid 1432 cases of cervical cancer (-63.3%) and 513 deaths (-63.4%) compared to screening only, with an incremental cost-effectiveness ratio (ICER) of 9569 euros per additional quality-adjusted life-year (QALY) gained. The sensitivity analysis highlighted that this model was robust to all parameters presenting uncertainties as the ICERs ranged from 2,781 euros to 48,122 euros per QALY gained.

CONCLUSION

This study showed that HPV vaccination in adolescent girls would be a beneficial and cost-effective public health programme in Italy.

Structural differences among cost-effectiveness models of human papillomavirus vaccines

In this article we compare previously published cost-effectiveness studies of human papillomavirus (HPV) vaccines along a defined subset of key model structural assumptions relating to HPV infection and disease, cervical cancer screening and HPV vaccination. For each structural aspect examined, we summarize assumptions from each study, provide a critical review and discuss the impact upon results. Considerable variation was observed across HPV vaccine cost-effectiveness models in a number of influential assumptions. Holding constant factors for which current data are lacking, the combined impact of assumptions made for the remaining parameters examined would appear to tend toward underestimation of the cost-effectiveness of HPV vaccination within existing studies. However, uncertainty concerning parameters, such as the duration of vaccine protection and acquired immunity following HPV infection, and the relationship between age and HPV virulence, complicates precise estimation of the cost-effectiveness of HPV vaccination and rigorous evaluation of the validity of existing modeling results.

Women's knowledge, attitudes, and intentions concerning Human Papillomavirus vaccination: findings of a waiting room survey of obstetrics-gynaecology outpatients

OBJECTIVE

To assess women's knowledge, attitudes, and behaviours related to Human Papillomavirus (HPV) and HPV vaccination.

METHODS

A self-administered questionnaire was completed by 98 women (90.7% response rate) attending a hospital-based obstetrics and gynaecology outpatient clinic in a mid-size Ontario city.

RESULTS

Women had a moderate level of knowledge of general HPV-related issues, but lacked information about the ability of barrier contraception to prevent HPV and about characteristics of HPV vaccination. Women were strongly supportive of HPV vaccination for both male and female teenagers, but reported low levels of intention to receive vaccination themselves. Physician recommendation was the most influential factor in women intention to be vaccinated, and younger women were more likely to say they intended to be vaccinated. HPV-related knowledge, level of education, and number of previous sexual partners were unrelated to women's intentions to receive HPV vaccination.

CONCLUSION

Findings indicate that women's knowledge about HPV vaccination is inconsistent, that women are supportive of vaccinating both male and female teenagers, and that physician recommendation and younger age are associated with women's interest in receiving the vaccine.

Health and economic implications of HPV vaccination in the United States

BACKGROUND

The cost-effectiveness of prophylactic vaccination against human papillomavirus types 16 (HPV-16) and 18 (HPV-18) is an important consideration for guidelines for immunization in the United States.

METHODS

We synthesized epidemiologic and demographic data using models of HPV-16 and HPV-18 transmission and cervical carcinogenesis to compare the health and economic outcomes of vaccinating preadolescent girls (at 12 years of age) and vaccinating older girls and women in catch-up programs (to 18, 21, or 26 years of age). We examined the health benefits of averting other HPV-16-related and HPV-18-related cancers, the prevention of HPV-6-related and HPV-11-related genital warts and juvenile-onset recurrent respiratory papillomatosis by means of the quadrivalent vaccine, the duration of immunity, and future screening practices.

RESULTS

On the assumption that the vaccine provided lifelong immunity, the cost-effectiveness ratio of vaccination of 12-year-old girls was $43,600 per quality-adjusted life-year (QALY) gained, as compared with the current screening practice. Under baseline assumptions, the cost-effectiveness ratio for extending a temporary catch-up program for girls to 18 years of age was $97,300 per QALY; the cost of extending vaccination of girls and women to the age of 21 years was $120,400 per QALY, and the cost for extension to the age of 26 years was $152,700 per QALY. The results were sensitive to the duration of vaccine-induced immunity; if immunity waned after 10 years, the cost of vaccination of preadolescent girls exceeded $140,000 per QALY, and catch-up strategies were less cost-effective than screening alone. The cost-effectiveness ratios for vaccination strategies were more favorable if the benefits of averting other health conditions were included or if screening was delayed and performed at less frequent intervals and with more sensitive tests; they were less favorable if vaccinated girls were preferentially screened more frequently in adulthood.

CONCLUSIONS

The cost-effectiveness of HPV vaccination will depend on the duration of vaccine immunity and will be optimized by achieving high coverage in preadolescent girls, targeting initial catch-up efforts to women up to 18 or 21 years of age, and revising screening policies.

Seroepidemiology as basis for design of a human papillomavirus vaccination program

We have performed a serological survey of HPV type 16-antibody prevalence by age and sex in Sweden and used it as a basis for modelling the optimal vaccination strategies in this population. Samples of 3,317 subjects were tested for HPV16-specific antibodies. The observed age-specific seroprevalences along with sexual behaviour data were used to infer parameter values for a mathematical model representing Sweden and the preventive effect of possible strategies estimated. By the year 2055, vaccination of females starting at age 12 in 2008 was most efficient, estimated to prevent 5.8 million cumulative HPV16 infections. Catch-up programs had a strong additional preventive effect. Vaccination also targeting males increased protective effect by about 4%, but had lower preventive effect per vaccination given. Addition of an HPV serosurvey to existing models and data has enabled us to estimate effect of different vaccination strategies, optimized to the HPV epidemiology in our population.

Measuring the effects of unintended pregnancy on women's quality of life

BACKGROUND

This study was conducted to assess the potential impact of an unintended pregnancy on women's quality of life.

STUDY DESIGN

We asked 192 nonpregnant women to report how they would feel if they learned that they were pregnant using a visual analog scale (VAS), a time trade-off (TTO) metric, a standard gamble (SG) metric and a willingness-to-pay (WTP) metric.

RESULTS

Women's anticipated responses to an unintended pregnancy varied widely. Using a VAS, 8% reported pregnancy would make them feel like they were dying. To avoid pregnancy, 28% of women were willing to trade time from the end of their life (TTO), 16% of women were willing to accept an immediate risk of death (SG) and 60% of women were willing to pay some amount of money (WTP). On average, women, using the VAS, TTO and SG metrics, reported that an unintended pregnancy would create a health utility state (where 0 represents death and 1 represents perfect health) of 0.487, 0.992 and 0.997, respectively.

CONCLUSION

The anticipated effects of pregnancy on women's quality of life should be integrated into cost-effectiveness analyses of family planning services.

Economic evaluation of human papillomavirus vaccination in the United Kingdom

OBJECTIVE

To assess the cost effectiveness of routine vaccination of 12 year old schoolgirls against human papillomavirus infection in the United Kingdom.

DESIGN

Economic evaluation.

SETTING

UK. Population Schoolgirls aged 12 or older.

MAIN OUTCOME MEASURES

Costs, quality adjusted life years (QALYs), and incremental cost effectiveness ratios for a range of vaccination options.

RESULTS

Vaccinating 12 year old schoolgirls with a quadrivalent vaccine at 80% coverage is likely to be cost effective at a willingness to pay threshold of pound30,000 (euro37,700; $59,163) per QALY gained, if the average duration of protection from the vaccine is more than 10 years. Implementing a catch-up campaign of girls up to age 18 is likely to be cost effective. Vaccination of boys is unlikely to be cost effective. A bivalent vaccine with the same efficacy against human papillomavirus types 16 and 18 costing pound13- pound21 less per dose (depending on the duration of vaccine protection) may be as cost effective as the quadrivalent vaccine although less effective as it does not prevent anogenital warts.

CONCLUSIONS

Routine vaccination of 12 year old schoolgirls combined with an initial catch-up campaign up to age 18 is likely to be cost effective in the UK. The results are robust to uncertainty in many parameters and processes. A key influential variable is the duration of vaccine protection.

Human papillomavirus types 16 and 18 vaccine (recombinant, AS04 adjuvanted, adsorbed) [Cervarix]

Cervarix is a prophylactic vaccine comprised of a mixture of virus-like particles derived from the L1 capsid proteins of human papillomavirus (HPV) types 16 and 18 formulated with the AS04 adjuvant system. It is administered by intramuscular injection as a three-dose vaccine regimen at 0, 1 and 6 months. The vaccine is indicated for the prevention of high-grade cervical intraepithelial neoplasia (CIN 2 and CIN 3) and cervical cancer causally related to HPV types 16 and 18. In randomized, double-blind, phase II or III trials in >19,000 women aged 15-25 years, the HPV 16/18 vaccine showed high efficacy in preventing CIN 2+ associated with HPV 16/18. Cross-protection against new incident or 6-month persistent HPV 45 or HPV 31 infection was also evident. Phase II follow-up was for at least 5.5 years, and the phase III interim analysis was at approximately 15 months after the first vaccine dose. In a bridging study, in adolescent girls aged 10-14 years, the HPV 16/18 vaccine induced twice the already high antibody titres as it did in young women (aged 15-25 years). The immune response in older women (aged 26-55 years) at 24 months in another study was >or= 8-fold higher than antibody levels reported in younger age groups. Anti-HPV 16/18 antibody responses were greater with an AS04-adjuvanted HPV 16/18 vaccine than with an aluminium salt-adjuvanted formulation. The HPV 16/18 vaccine was generally well tolerated and injection-site reactions were the most common vaccine-related adverse events reported.

Coverage of cervical cancer screening in 57 countries: low average levels and large inequalities

Emmanuela Gakidou and colleagues find that coverage of cervical cancer screening in developing countries is on average 19% compared to 63% in developed countries.

Cost-effectiveness analysis of adding a quadrivalent HPV vaccine to the cervical cancer screening programme in Switzerland

OBJECTIVE

Based on positive safety and efficacy data, a quadrivalent Human PapillomaVirus (HPV) vaccine has been approved in Switzerland to prevent HPV types 6, 11, 16 and 18 infections. The objective of this study was to explore the cost-effectiveness of an HPV vaccination in Switzerland.

DESIGN AND METHODS

A Markov model of the natural history of HPV infection was adapted to the Swiss context and followed a hypothetical cohort of 41,200 girls aged 11 years over their lifetime. Main epidemiological and economic parameters were extracted from the literature. Two strategies were compared: conventional cytological screening only and HPV vaccination followed by conventional cytological screening. A coverage rate of 80% was used and the vaccine was assumed to provide a lifelong protection. Analyses were performed from the direct health care cost perspective including only direct medical costs.

RESULTS

Compared to screening only, adding a quadrivalent HPV vaccine could prevent over lifetime 62% of cervical cancers and related deaths, 19% of Cervical Intraepithelial Neoplasia (CIN 1), 43% of CIN 2, 45% of CIN 3 and 66% of genital warts per cohort. Incremental cost-effectiveness ratios (ICER) were estimated to be CHF 45,008 per Life Year Gained (LYG) and CHF 26,005 per Quality Adjusted Life Year (QALY) gained. Sensitivity analyses demonstrated that the ICER was robust to all parameters, but was most sensitive to the need for a booster and discount rates.

CONCLUSIONS

Compared to commonly accepted standard thresholds in Europe and other vaccination strategies implemented in Switzerland, adding a quadrivalent HPV vaccine alongside the current cervical cancer screening programme is likely to be cost-effective in Switzerland.

Evaluating human papillomavirus vaccination programs in Canada: should provincial healthcare pay for voluntary adult vaccination?

Background

Recently, provincial health programs in Canada and elsewhere have begun rolling out vaccination against human papillomavirus for girls aged 9–13. While vaccination is voluntary, the cost of vaccination is waived, to encourage parents to have their daughters vaccinated. Adult women who are eligible for the vaccine may still receive it, but at a cost of approximately CAN$400. Given the high efficacy and immunogenicity of the vaccine, the possibility of eradicating targeted types of the virus may be feasible, assuming the vaccination programs are undertaken strategically.

Methods

We develop a mathematical model to describe the epidemiology of vaccination against human papillomavirus, accounting for a widespread childhood vaccination program that may be supplemented by voluntary adult vaccination. A stability analysis is performed to determine the stability of the disease-free equilibrium. The critical vaccine efficacy and immunogenicity thresholds are derived, and the minimum level of adult vaccination required for eradication of targeted types is determined.

Results

We demonstrate that eradication of targeted types is indeed feasible, although the burden of coverage for a childhood-only vaccination program may be high. However, if a small, but non-negligible, proportion of eligible adults can be vaccinated, then the possibility of eradication of targeted types becomes much more favourable. We provide a threshold for eradication in general communities and illustrate the results with numerical simulations. We also investigate the effects of suboptimal efficacy and immunogenicity and show that there is a critical efficacy below which eradication of targeted types is not possible. If eradication is possible, then there is a critical immunogenicity such that even 100% childhood vaccination will not eradicate the targeted types of the virus and must be supplemented with voluntary adult vaccination. However, the level of adult vaccination coverage required is modest and may be achieved simply by removing the cost burden to vaccination.

Conclusion

We recommend that provincial healthcare programs should pay for voluntary adult vaccination for women aged 14–26. However, it should be noted that our model results are preliminary, in that we have made a number of simplifying assumptions, including a lack of age-dependency in sexual partner rates, a lack of sexual activity outside of the vaccine age-range among females and a uniform age of sexual debut; thus, further work is desired to enhance the external generalisability of our results.

Cost-effectiveness of cervical cancer screening with human papillomavirus DNA testing and HPV-16,18 vaccination

BACKGROUND

The availability of human papillomavirus (HPV) DNA testing and vaccination against HPV types 16 and 18 (HPV-16,18) motivates questions about the cost-effectiveness of cervical cancer prevention in the United States for unvaccinated older women and for girls eligible for vaccination.

METHODS

An empirically calibrated model was used to assess the quality-adjusted life years (QALYs), lifetime costs, and incremental cost-effectiveness ratios (2004 US dollars per QALY) of screening, vaccination of preadolescent girls, and vaccination combined with screening. Screening varied by initiation age (18, 21, or 25 years), interval (every 1, 2, 3, or 5 years), and test (HPV DNA testing of cervical specimens or cytologic evaluation of cervical cells with a Pap test). Testing strategies included: 1) cytology followed by HPV DNA testing for equivocal cytologic results (cytology with HPV test triage); 2) HPV DNA testing followed by cytology for positive HPV DNA results (HPV test with cytology triage); and 3) combined HPV DNA testing and cytology. Strategies were permitted to switch once at age 25, 30, or 35 years.

RESULTS

For unvaccinated women, triennial cytology with HPV test triage, beginning by age 21 years and switching to HPV testing with cytology triage at age 30 years, cost $78,000 per QALY compared with the next best strategy. For girls vaccinated before age 12 years, this same strategy, beginning at age 25 years and switching at age 35 years, cost $41,000 per QALY with screening every 5 years and $188,000 per QALY screening triennially, each compared with the next best strategy. These strategies were more effective and cost-effective than screening women of all ages with cytology alone or cytology with HPV triage annually or biennially.

CONCLUSIONS

For both vaccinated and unvaccinated women, age-based screening by use of HPV DNA testing as a triage test for equivocal results in younger women and as a primary screening test in older women is expected to be more cost-effective than current screening recommendations.