Vaccinating adolescents against meningococcal disease in Canada: a cost-effectiveness analysis

Cost-effectiveness analysis of vaccination strategies against meningococcal disease for children under nine years of age in China

Meningococcal vaccination strategies in China are intricate, including multiple vaccines targeting different serogroups. The current National Immunization Program (NIP) includes two polysaccharide vaccines for serogroups A and C (MPV-A and MPV-AC), covering limited serogroups and requiring adaptation. This study aims to evaluate the cost-effectiveness of replacing the current strategy with alternative strategies utilizing non-NIP vaccines to inform policy decisions. From a societal perspective, a decision tree-Markov model was constructed to simulate the economic and health consequences of meningococcal disease in a 2019 birth cohort with four vaccination strategies. Epidemiology, vaccine efficacy, cost, and other parameters were derived from previous studies. We conducted sensitivity analyses to assess the robustness of the findings and explored prices for non-NIP vaccines that enable cost-effective strategies. Compared to the current strategy, alternative strategies using quadrivalent polysaccharide vaccine (MPV-4), bivalent conjugate vaccine (MCV-AC), and quadrivalent conjugate vaccine (MCV-4) could avoid 91, 286, and 455 more meningococcal cases. The ICERs were estimated at approximately $250 thousand/QALY, $450 thousand/QALY, and $1.5 million/QALY, all exceeding the threshold of three times GDP per capita. The alternative strategies were not cost-effective. However, if vaccine prices were reduced to $3.9 for MPV-4, $9.9 for MCV-AC, and $12 for MCV-4, the corresponding strategy would be cost-effective. The current meningococcal vaccination strategy in China could effectively prevent the disease at a low cost, but with limited serogroup coverage. Strategies using MPV-4, MCV-AC, or MCV-4 could increase health benefits at a substantial cost, and might become cost-effective if vaccine prices decrease.

Cost-effectiveness of meningococcal vaccination of Norwegian teenagers with a quadrivalent ACWY conjugate vaccine

In Norway, the incidence of invasive meningococcal disease (IMD) is higher among 16–19-year-olds than in the general population. Most IMD cases among teenagers are caused by serogroup Y. Since 2011, one dose of meningococcal ACWY conjugate vaccine (MCV4) has been recommended for teenagers with out-of-pocket payment. The teenagers are usually vaccinated through the school health service at age 18. This study aimed to estimate costs and health gains of introducing MCV4 to Norwegian teenagers through the national immunization program (NIP). A Markov model was used to analyze the cost-effectiveness of universal MCV4 vaccination of either 15-year-olds or 18-years-olds. Occurrences of IMD were simulated from 15 until 23 years of age. Costs were estimated from a healthcare perspective. Sensitivity analyses evaluated the impact of vaccine price, vaccination uptake, IMD incidence and discount rate. Compared to today’s practice of vaccinating 18-year-olds with out-of-pocket payment, introducing MCV4 to 15-year-olds in a NIP-setting, with 90% vaccine uptake and 50% rebate on vaccine price, prevented 3.2 hospitalizations, 0.20 sequelae and 0.47 deaths among 15–23-year-olds, annually. Total costs were reduced by €30,000 and 9.7 quality-adjusted life-years (QALYs) were gained per birth cohort. The probability of cost-effectiveness was 99.0%, assuming a willingness-to-pay threshold of €86,000/QALY for severe diseases in Norway. Cost-effectiveness was highly dependent on vaccine price. Vaccination of 18-year-olds in a NIP-setting was also cost-effective, but less than NIP-vaccination of 15-year-olds. Introduction of MCV4 to the 15-year-olds in the Norwegian NIP is likely to be cost-effective given a rebate on the vaccine price.

Use of Cost-Effectiveness Analyses for Decisions About Vaccination Programs for Meningococcal Disease in the United States, United Kingdom, The Netherlands, and Canada

INTRODUCTION

Meningococcal vaccines to protect against invasive meningococcal disease (IMD) vary in terms of vaccine technology and serogroup coverage (Polysaccharide MnACWY, conjugated C and ACWY, outer membrane vesicle-based or protein-based B vaccines), and the national recommendations for each of them vary in terms of target population and number of doses. We sought to understand factors associated with the evolution of meningococcal vaccination program recommendations in four countries with formal evaluation processes: the UK, US, the Netherlands, and Canada.

AREAS COVERED

A targeted review of published literature and internet sources for the four countries relating to meningococcal vaccination decision-making was conducted. The review focused on the impact of cost-effectiveness analyses on vaccine policy decisions and the extent to which variation in incidence of IMD and its potential catastrophic consequences influenced policy decisions.The evolution of meningococcal vaccine recommendations in the four countries was mainly driven by changes in vaccine availability and changes in serogroup incidence. Public pressure due to the catastrophic nature of IMD influenced recommendations. The role of cost-effectiveness analyses varied across the 4 countries.

EXPERT OPINION

The value of implementing meningococcal vaccination programs should be assessed using factors beyond those included in traditional cost-effectiveness analyses.

Economic evaluation of meningococcal vaccines: considerations for the future

In 2018, a panel of health economics and meningococcal disease experts convened to review methodologies, frameworks, and decision-making processes for economic evaluations of vaccines, with a focus on evaluation of vaccines targeting invasive meningococcal disease (IMD). The panel discussed vaccine evaluation methods across countries; IMD prevention benefits that are well quantified using current methods, not well quantified, or missing in current cost-effectiveness methodologies; and development of recommendations for future evaluation methods. Consensus was reached on a number of points and further consideration was deemed necessary for some topics. Experts agreed that the unpredictability of IMD complicates an accurate evaluation of meningococcal vaccine benefits and that vaccine cost-effectiveness evaluations should encompass indirect benefits, both for meningococcal vaccines and vaccines in general. In addition, the panel agreed that transparency in the vaccine decision-making process is beneficial and should be implemented when possible. Further discussion is required to ascertain: how enhancing consistency of frameworks for evaluating outcomes of vaccine introduction can be improved; reviews of existing tools used to capture quality of life; how indirect costs are considered within models; and whether and how the weighting of quality-adjusted life-years (QALY), application of QALY adjustment factors, or use of altered cost-effectiveness thresholds should be used in the economic evaluation of vaccines.

Cost-effectiveness of alternative strategies for vaccination of adolescents against serogroup B IMD with the MenB-FHbp vaccine in Canada

OBJECTIVE

Serogroup B meningococci (MnB) are now the largest cause of invasive meningococcal disease (IMD) in Canada. We assessed the clinical and economic impact of 3 adolescent MenB-FHbp immunization strategies.

METHODS

A population-based dynamic transmission model was developed to simulate the transmission of MnB among the entire Canadian population over a 30-year time horizon. Age group-based IMD incidence, bacterial carriage and transmission, disease outcomes, costs, and impact on quality of life were obtained from Canadian surveillance data and published literature. The vaccine was assumed to provide 85% protection against IMD and 26.6% against carriage acquisition. The model estimated the impact of routine vaccination with MenB-FHbp in 3 strategies: (1) age 14, along with existing school-based programs, with 75% uptake; (2) age 17 with 75% uptake, assuming school vaccination; and (3) age 17 with 30% uptake, assuming vaccination outside of school. Costs were calculated from the Canadian societal perspective.

RESULTS

With no vaccination, an estimated 3974 MnB cases would be expected over 30 years. Vaccination with strategies 1-3 were estimated to avert 688, 1033, and 575 cases, respectively. These outcomes were associated with incremental costs per quality-adjusted life-year of $976,000, $685,000, and $490,000.

CONCLUSIONS

Our model indicated that if the vaccine reduces risk of carriage acquisition, vaccination of older adolescents, even at lower uptake, could have a significant public health impact. Due to low disease incidence, MnB vaccination is unlikely to meet widely accepted cost-effectiveness thresholds, but evaluations of new programs should consider the overall benefits of the vaccination.

Epidemiology and Control of Meningococcal Disease in Canada: A Long, Complex, and Unfinished Story

The epidemiology of meningococcal disease in Canada has been punctuated by outbreaks caused by serogroup A strains in the 1940s, virulent serogroup C clones from 1985 to 2001, a serogroup B clone in Quebec from 2003 to 2014, and more recently a W clone in British Columbia. Region- and province-wide immunization campaigns have been implemented to control these outbreaks using meningococcal C polysaccharide and conjugate vaccines, a quadrivalent ACWY conjugate vaccine, and a serogroup B protein-based vaccine. Meningococcal C conjugate vaccines have been included in routine immunization programs for children, and ACWY conjugate vaccines have been included in school-based programs for adolescents in most jurisdictions. In contrast, serogroup B protein-based vaccines were only recommended and used for high-risk individuals and to control outbreaks. Currently, the immunization schedules adopted in provinces and territories are not uniform. This is not explained by notable epidemiologic differences. Publicly funded immunization programs are the result of a complex decision-making process. Political factors including public opinion, media attention, interest groups' advocacy campaigns, decision-makers' priorities and budgetary constraints have played important roles in shaping meningococcal programs in Canada, and this should be recognized. As the recent occurrence of outbreaks caused by virulent W clones shows, continued investments in epidemiological surveillance at both the provincial and national levels are necessary, so there can be early warning and informed decisions can be made.

Lifetime costs of invasive meningococcal disease: A Markov model approach

INTRODUCTION

Invasive meningococcal disease (IMD) is an uncommon but life-threatening infectious disease associated with high sequelae rates in young children and an increased risk of mortality in adolescents and young adults. Funding decisions to reject inclusion of new meningococcal serogroup B vaccines on national immunisation schedules have been criticised by IMD patients, their families, paediatricians and charity organisations. We aim to estimate the lifetime costs of IMD with the best available evidence to inform cost-effectiveness analyses.

METHODS

A Markov model was developed taking healthcare system and societal perspectives. A range of data including age-specific mortality rates, and probabilities of IMD-related sequelae were derived from a systematic review and meta-analysis. All currencies were inflated to year 2017 prices by using consumer price indexes in local countries and converted to US dollars by applying purchasing power parities conversion rates. Expert panels were used to inform the model development process including key structural choices and model validations.

RESULTS

The estimated lifetime societal cost is US$319,896.74 per IMD case including the direct healthcare cost of US$65,035.49. Using a discount rate of 5%, the costs are US$54,278.51 and US$13,968.40 respectively. Chronic renal failure and limb amputation result in the highest direct healthcare costs per patient. Patients aged < 5 years incur the higher healthcare expenditure compared with other age groups. The costing results are sensitive to the discount rate, disease incidence, acute admission costs, and sequelae rates and costs of brain injuries and epilepsy.

CONCLUSIONS

IMD can result in substantial costs to the healthcare system and society. Understanding the costs of care can assist decision-making bodies in evaluating cost-effectiveness of new vaccine programs.

Cost-effectiveness of meningococcal polysaccharide serogroups A, C, W-135 and Y conjugate vaccine in Australian adolescents

OBJECTIVES

The incidence of invasive meningitis disease (IMD) is increasing in Australia. A conjugate vaccine of meningococcal polysaccharide serogroups A, C, W and Y (MenACWY) is currently indicated for infants aged 12 months on the Australian National Immunisation Program. This study sought to determine the cost-effectiveness of a broader MenACWY vaccination program for Australians aged 15 to 19 years.

METHODS

A Markov model was constructed to simulate the incidence and consequences of IMD in Australians aged 0-84 years, with follow up until age 85 years. The model comprised four health states: 'Alive with no previous IMD', 'Alive, post IMD without long-term complications', 'Alive, post IMD with long-term complications' and 'Dead'. Decision analysis compared the clinical consequences and costs of a vaccination program versus no vaccination from the perspective of the Australian health care system. Age-specific incidence of IMD and fatality rates were derived from Australian surveillance data. Vaccine coverage, vaccine efficacy and herd immunity were based on published data. The total cost for MenACWY vaccination was AU$56 per dose. Costs and health outcomes were discounted by 5% per annum (in the base-case analysis).

RESULTS

Compared to no vaccination, a MenACWY vaccination program targeted at Australians aged 15-19 years was expected to prevent 1664 IMD cases in the Australian population aged 0-84 years followed up until age 85 years. The program would lead to 1131 life years (LYs) and 2058 quality adjusted life years (QALYs) gained at a total cost of AU$115 million (all discounted values). These equated to incremental cost-effectiveness ratios of AU$101,649 per LY gained and AU$55,857 per QALY gained. A probabilistic sensitivity analysis demonstrated a likelihood of cost-effectiveness of 34.6%, assuming a willingness to pay threshold of AU$50,000 per QALY gained.

CONCLUSION

The likelihood of this program being cost-effective under a willingness to pay threshold AU$50,000 per QALY gained is 35%.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cost-effectiveness Comparison of Monovalent C Versus Quadrivalent ACWY Meningococcal Conjugate Vaccination in Canada

BACKGROUND

In Quebec, 1 dose of monovalent C meningococcal conjugate vaccine (Men-C-Con) is offered at 12 months of age and a booster dose in grade 9 (14-15 years of age). In other Canadian provinces, a quadrivalent vaccine against serogroups ACWY (Men-4-Con) is increasingly used for adolescents. An economic analysis was performed to assess the value of a switch from Men-C-Con to Men-4-Con.

METHODS

A compartmental static simulation model was developed to assess the burden of invasive meningococcal disease due to serogroups AWY (AWY-IMD) in a cohort of 100,000 persons with different vaccination programs. Univariate and multivariate sensitivity analyses were performed, including variation in vaccine price difference ($12; range: $0-$20), AWY-IMD rate (0.08/100,000 to 0.28/100,000 person-years), level of herd immunity generated by adolescent vaccination (from zero to disease elimination) and discounting rate (0%, 3% or 6%).

RESULTS

In the low AWY-IMD rate base scenario, replacing Men-C-Con by Men-4-Con for adolescents would reduce disease burden by 16% (no herd effect) to 58% (moderate herd effect), with an incremental cost-effectiveness ratios between $445,000 per quality-adjusted life-year (QALY) and $167,000/QALY in a societal perspective. In the high AWY-IMD rate scenario, incremental cost-effectiveness ratio would be in the range of $97,000/QALY to $19,000/QALY.

CONCLUSION

Based on the epidemiologic conditions in Quebec and in most other Canadian provinces, the benefits of Men-4-Con in reducing the burden of disease would be low for a high cost. The switch would, however, be more economically attractive with a much higher incidence rate (as in a few provinces) or with a reduced vaccine price in conditions assuming a moderate to high herd effect.

Economic evaluations of vaccines in Canada: a scoping review

BACKGROUND

This study aims to summarise and describe the evolution of published economic evaluations of vaccines in Canada, thereby outlining the current state of this expanding and meaningful research.

METHODS

Using Arksey and O'Malley's scoping review framework we assembled relevant research from both academic and grey literature. Following abstract and full-text review we identified 60 articles to be included in the final analysis.

RESULTS

We found that since 1988 there has been a steady increase in the number of economic evaluations on vaccines in Canada. Many of these studies focus on the more recently licensed vaccines, such as influenza (16.7%), human papillomavirus (15.0%) and pneumococcal disease (15.0%). Since 2010 economic evaluations of vaccines have shown increased adherence to economic evaluation guidelines (OR = 4.6, CI 1.33, 18.7), suggesting there has been improvement in the consistency and transparency of these studies. However, there remains room for improvement, for instance, we found evidence that studies who stated a conflict of interest are more likely to assert the vaccine of interest was cost-effective (OR = 7.4; CI 1.04, 17.8). Furthermore, most reports use static models that do not consider herd immunity, and only a few evaluate vaccines post-implementation (ex-post) and traveller's vaccinations.

CONCLUSION

Researchers should examine identified research gaps and continue to improve standardization and transparency when reporting to ensure economic evaluations of vaccines best meet the needs of policy-makers, other researchers and the public.

Cost-effectiveness of alternate strategies for childhood immunization against meningococcal disease with monovalent and quadrivalent conjugate vaccines in Canada

BACKGROUND

Public health programs to prevent invasive meningococcal disease (IMD) with monovalent serogroup C meningococcal conjugate vaccine (MCV-C) and quadrivalent meningococcal conjugate vaccines (MCV-4) in infancy and adolescence vary across Canadian provinces. This study evaluated the cost-effectiveness of various vaccination strategies against IMD using current and anticipated future pricing and recent epidemiology.

METHODS

A cohort model was developed to estimate the clinical burden and costs (CAN$2014) of IMD in the Canadian population over a 100-year time horizon for three strategies: (1) MCV-C in infants and adolescents (MCV-C/C); (2) MCV-C in infants and MCV-4 in adolescents (MCV-C/4); and (3) MCV-4 in infants (2 doses) and adolescents (MCV-4/4). The source for IMD incidence was Canadian surveillance data. The effectiveness of MCV-C was based on published literature. The effectiveness of MCV-4 against all vaccination regimens was assumed to be the same as for MCV-C regimens against serogroup C. Herd effects were estimated by calibration to estimates reported in prior analyses. Costs were from published sources. Vaccines prices were projected to decline over time reflecting historical procurement trends.

RESULTS

Over the modeling horizon there are a projected 11,438 IMD cases and 1,195 IMD deaths with MCV-C/C; expected total costs are $597.5 million. MCV-C/4 is projected to reduce cases of IMD by 1,826 (16%) and IMD deaths by 161 (13%). Vaccination costs are increased by $32 million but direct and indirect IMD costs are projected to be reduced by $46 million. MCV-C/4 is therefore dominant vs. MCV-C/C in the base case. Cost-effectiveness of MCV-4/4 was $111,286 per QALY gained versus MCV-C/4 (2575/206 IMD cases/deaths prevented; incremental costs $68 million).

CONCLUSIONS

If historical trends in Canadian vaccines prices continue, use of MCV-4 instead of MCV-C in adolescents may be cost-effective. From an economic perspective, switching to MCV-4 as the adolescent booster should be considered.

Economic evaluation of vaccines in Canada: A systematic review

BACKGROUND

Economic evaluations should form part of the basis for public health decision making on new vaccine programs. While Canada's national immunization advisory committee does not systematically include economic evaluations in immunization decision making, there is increasing interest in adopting them. We therefore sought to examine the extent and quality of economic evaluations of vaccines in Canada.

OBJECTIVE

We conducted a systematic review of economic evaluations of vaccines in Canada to determine and summarize: comprehensiveness across jurisdictions, studied vaccines, funding sources, study designs, research quality, and changes over time.

METHODS

Searches in multiple databases were conducted using the terms "vaccine," "economics" and "Canada." Descriptive data from eligible manuscripts was abstracted and three authors independently evaluated manuscript quality using a 7-point Likert-type scale scoring tool based on criteria from the International Society for Pharmacoeconomics and Outcomes Research (ISPOR).

RESULTS

42/175 articles met the search criteria. Of these, Canada-wide studies were most common (25/42), while provincial studies largely focused on the three populous provinces of Ontario, Quebec and British Columbia. The most common funding source was industry (17/42), followed by government (7/42). 38 studies used mathematical models estimating expected economic benefit while 4 studies examined post-hoc data on established programs. Studies covered 10 diseases, with 28/42 addressing pediatric vaccines. Many studies considered cost-utility (22/42) and the majority of these studies reported favorable economic results (16/22). The mean quality score was 5.9/7 and was consistent over publication date, funding sources, and disease areas.

CONCLUSIONS

We observed diverse approaches to evaluate vaccine economics in Canada. Given the increased complexity of economic studies evaluating vaccines and the impact of results on public health practice, Canada needs improved, transparent and consistent processes to review and assess the findings of the economic evaluations of vaccines.

Epidemiological impact and cost-effectiveness of introducing vaccination against serogroup B meningococcal disease in France

INTRODUCTION

Despite its low incidence in France, invasive serogroup B meningococcal disease remains a public health concern. A new vaccine against the disease, Bexsero(®), has been licensed in the EU. We studied the epidemiological impact and cost-effectiveness of routine vaccination using Bexsero(®) in order to inform the decision-making process regarding its potential inclusion in the vaccination schedule.

METHODS

A multi-generational Markov model was used. Time horizon was set to 100 years. Five vaccination strategies were evaluated: infants at 3, 5, 6 and 13 months, toddlers at 13, 15 and 27 months and adolescents at 15 years provided 2 doses one month apart. A booster dose at 15 years old and a catch-up for 15 years old subjects during the first 15 years of the programme were added to the infant and toddler strategies. Costs per QALY gained were computed from a restricted societal perspective including direct costs only. Herd immunity was simulated in an alternative base-case scenario and sensitivity analyses.

RESULTS

In the base-case analysis without herd immunity and with all cohorts vaccinated, at € 40 per vaccine dose, routine infant vaccination would provide the lowest cost per QALY gained (€ 380,973) despite only preventing 18% of cases. Under the assumption of herd immunity, the adolescent vaccination would provide the lowest cost per QALY gained (€ 135,902) preventing 24% of cases. Infant vaccination with a late booster and catch-up would prevent 51% of cases with a cost of € 188,511 per QALY gained.

CONCLUSIONS

Given current meningococcal epidemiology in France and the available data on the protection provided by Bexsero(®), our modelling work showed that routine vaccination against serogroup B meningococcal disease is not cost-effective.

Routinely vaccinating adolescents against meningococcus: targeting transmission & disease

Adolescents have the highest rates of meningococcal carriage and transmission. Interrupting the adolescent habitat in order to reduce carriage and transmission within adolescents and to other age groups could help to control meningococcal disease at a population level. Compared to immunization strategies restricted to young children, a strategy focused on adolescents may have more profound and long-lasting indirect impacts, and may be more cost effective. Despite challenges in reaching this age-group, experience with other vaccines show that high vaccine coverage of adolescents is attainable.

Sources and Characteristics of Utility Weights for Economic Evaluation of Pediatric Vaccines: A Systematic Review

BACKGROUND

Cost-effectiveness analysis of pediatric vaccines for infectious diseases often requires quality-of-life (utility) weights.

OBJECTIVE

To investigate how utility weights have been elicited and used in this context.

METHODS

A systematic review was conducted of studies published between January 1990 and July 2013 that elicited or used utility weights in cost-effectiveness analyses of vaccines for pediatric populations. The review focused on vaccines for 17 infectious diseases and is presented following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology.

RESULTS

A total of 6410 titles and abstracts and 225 full-text articles were reviewed. Of those selected for inclusion (n = 101), 15 articles described the elicitation of utility weights and 86 described economic modeling studies using utilities. Various methods were used to generate utilities, including time trade-off, contingent valuation, and willingness to pay, as well as a preference-based measure with associated value sets, such as the EuroQol five-dimensional questionnaire or the Health Utilities Index. In modeling studies, the source of utilities used was often unclear, poorly reported, or based on weak underlying evidence. We found no articles that reported on the elicitation or use of utilities in diphtheria, polio, or tetanus.

CONCLUSIONS

The scarcity of appropriate utility weights for vaccine-preventable infectious diseases in children and a lack of standardization in their use in economic assessments limit the ability to accurately assess the benefits associated with interventions to prevent infectious diseases. This is an issue that should be of concern to those making decisions regarding the prevention and treatment of infectious childhood illnesses.

Long-term seroprotection after an adolescent booster meningococcal serogroup C vaccination

OBJECTIVES

To determine long-term seroprotection after serogroup C meningococcal (MenC) vaccination at the age of 9-12 years, with or without booster vaccination at the age of 13-15 years.

DESIGN

Observational cohort study; follow-on from randomised study.

SETTING

Participants were recruited from English secondary schools (in Oxfordshire and Buckinghamshire).

PARTICIPANTS AND INTERVENTIONS

Participants were primed with MenC CRM-glycoconjugate vaccine at the age of 9-12 years in the UK routine immunisation campaign. In previous studies they were randomised at 13 to 15 years of age to receive a booster dose of MenC-CRM glycoconjugate vaccine (CRM-group) or bivalent meningococcal serogroup A/C polysaccharide vaccine (PS-group), or they received no additional doses of MenC vaccine (control group). In this follow-on study, a blood sample was obtained 11 years after primary immunisation. Of 531 individuals eligible to participate, 134 were enrolled, and 124 were included in the analysis.

MAIN OUTCOME MEASURES

MenC serum bactericidal antibody (SBA) geometric mean titre; proportion of participants with SBA titre ≥8 (putative protective threshold).

RESULTS

Median ages at priming, boosting and blood sampling were 10.61, 14.42 and 22.11 years, respectively. Geometric mean titres for MenC SBA were: CRM group 1373 (95% CI 954 to 1977); PS group 1024 (687 to 1526); and controls 284 (167 to 483). SBA titres ≥8 were present in 50/54 (92.6%) controls and 70/70 (100%) boosted individuals.

CONCLUSIONS

The planned introduction in the UK of an adolescent booster of MenC conjugate vaccine in 2013 is likely to provide sustained protection against MenC disease.

TRIAL REGISTRATION

Registered on ClinicalTrials.gov (NCT01459432).

Meningococcal serogroup A, C, W₁₃₅ and Y conjugated vaccine: a cost-effectiveness analysis in the Netherlands

Background

In 2002, vaccination with a serogroup C meningococcal conjugate vaccine (MenC) was introduced in the Netherlands for all children aged 14 months. Despite its success, herd immunity may wane over time. Recently, a serogroup A,C,W135,Y meningococcal conjugate vaccine (MenACWY) was licensed for use in subjects of 12 months of age and above.

Objectives

To evaluate the cost-effectiveness of meningococcal vaccination at 14 months and an additional vaccination at the age of 12 years, both with the MenACWY vaccine.

Methods

A decision analysis cohort model, with 185,000 Dutch newborns, was used to evaluate the cost-effectiveness of different immunization strategies. For strategies including a vaccination at 12 years of age, an additional cohort with adolescents aged 12 years was followed. The incremental cost-effectiveness ratio (ICER) was estimated for the current disease incidence and for a scenario when herd immunity is lost.

Results

Vaccination with MenACWY at 14 months is cost-saving. Vaccinating with MenACWY at 14 months and at 12 years would prevent 7 additional cases of meningococcal serogroup A,C,W135,Y disease in the birth cohort and adolescent cohort followed for 99 years compared to the current vaccine schedule of a single vaccination with MenC at 14 months. With the current incidence, this strategy resulted in an ICER of €635,334 per quality adjusted life year. When serogroup C disease incidence returns to pre-vaccination levels due to a loss of vaccine-induced herd-immunity, vaccination with MenACWY at 14 months and at 12 years would be cost-saving.

Conclusions

Routine vaccination with MenACWY is cost-saving. With the current epidemiology, a booster-dose with MenACWY is not likely cost-effective. When herd immunity is lost, a booster-dose has the potential of being cost-effective. A dynamic model should be developed for more precise estimation of the cost-effectiveness of the prevention of disappearance of herd immunity.

Categorization of methods used in cost-effectiveness analyses of vaccination programs based on outcomes from dynamic transmission models

The aim of this study is to categorize methods used to estimate the cost-effectiveness of vaccination programs using dynamic transmission models, and assess value to decision-makers. A targeted literature search of PubMed has been carried out for this purpose. A review of 43 articles presenting cost-effectiveness analyses of vaccination programs based on dynamic transmission models identified four methods for the estimation of a cost-effectiveness ratio: cumulative population values over a fixed time horizon; population values for a steady-state year; cohort values from time of program initiation; and cohort values at steady state. Cost-effectiveness estimates are sensitive to the choice of time horizon or number of cohorts included. Estimates at steady state are the most comparable to estimates for other healthcare interventions but do not account for pre-steady-state periods. Population values provide estimates of budget impact. In conclusion, four different methods were identified for converting clinical outcomes from a dynamic transmission model to cost-effectiveness estimates. Sensitivity analyses for time horizon or number of cohorts considered should be routinely performed.

Persistence of serum bactericidal antibody one year after a booster dose of either a glycoconjugate or a plain polysaccharide vaccine against serogroup C Neisseria meningitidis given to adolescents previously immunized with a glycoconjugate vaccine

BACKGROUND

Bactericidal antibody induced by immunization of infants with serogroup C Neisseria meningitidis (MenC) vaccines wanes rapidly during childhood. Adolescents are at particular risk from meningococcal disease, therefore they might benefit from a booster dose of vaccine. The duration of serologic response to such a booster in adolescents is unknown.

METHODS

In a previous study, English schoolchildren, aged 9 to 12 years, who had received a monovalent MenC glycoconjugate vaccine in 1999-2000, were given either a plain polysaccharide vaccine (MenC-PS group, n = 150) or a glycoconjugate vaccine (MenC-CRM group, n = 95) at 13 to 15 years of age. In this follow-up study, serum bactericidal antibody titers and specific immunoglobulin G concentrations were assessed 1 year later. Results were compared with unboosted controls of similar age (control group, n = 298).

RESULTS

Compliance with study protocol was achieved for 146 of the MenC-PS group, 92 of the MenC-CRM group, and 293 of the control group. Compared with the control group, both the MenC-PS and MenC-CRM groups had a significantly higher (P < 0.0001) geometric mean serum bactericidal antibody titers 1 year after the booster dose (geometric mean titers for MenC-PS group 3388 [95% confidence interval {CI}: 2460-4665]; MenC-CRM group 4417 [95% CI: 2951-6609]; control group 316 [95% CI: 252-396]). Specific immunoglobulin G concentration also rose and remained elevated 1 year after the booster.

CONCLUSIONS

A booster dose of MenC vaccine given to adolescents produced a marked rise in bactericidal antibody, which remained elevated 1 year later. Introduction of an adolescent booster of MenC vaccine might provide enhanced long-term population control of the disease.

Recombinant protein meningococcal serogroup B vaccine combined with outer membrane vesicles

INTRODUCTION

Meningococcal infection is a major cause of morbidity and mortality worldwide. Infection with Neisseria meningitidis is most common in young children, teenagers and people with certain medical conditions. Effective polysaccharide and glycoconjugate vaccines for serogroups A, C, W135 and Y have been developed. A similar capsular polysaccharide approach for serogroup B (MenB) has by most been judged as unsuitable, hence, no broad coverage vaccine has been licensed to date. The novel vaccine Bexsero (previously 4CMenB) has been developed and proven safe and immunogenic in clinical trials.

AREAS COVERED

The authors outline the constituents of Bexsero and immunogenicity and safety data from preclinical and clinical trials published in peer-reviewed literature, meeting proceedings and publicly-available clinical trial websites from 2000 to 2010.

EXPERT OPINION

Bexsero is well tolerated with a proven safety profile, and has demonstrated a robust immune response across different age groups against a range of diverse MenB strains. These data suggest that Bexsero has the ability to provide protection in infants, who are at the greatest risk of developing meningococcal disease.

Meningococcal serogroup C conjugate vaccination in Canada: how far have we progressed? How far do we have to go?

Since routine meningococcal C conjugate vaccination was introduced into Canada in 2002, there have been a large regional variation in the routine programs, changes to the timing of the infant series in some provinces, and wide differences in catch-up programs. As immunization is viewed as a provincial responsibility, less attention has been paid to determining national coverage rates and the direct and indirect effects of the widely varying provincial/territorial vaccination programs on the nation as a whole. Canada's disjointed regional immunization campaigns leave the population at risk of disease for an extended length of time. The United Kingdom has proven that with a pro-active approach to planning, coordination, and implementation of a national immunization program, excellent long-term control of invasive meningococcal disease in a large population could be achieved in as little as one year. A summation of the current meningococcal immunization strategies used in Canada and an estimate of overall vaccine coverage of children and youth is provided.

Serogroup C Neisseria meningitidis invasive infection: analysis of the possible vaccination strategies for a mass campaign

The serogroup C meningococcal conjugate vaccine is available since 1999. In the absence of randomized controlled trials that support a specific schedule, each country has adopted different vaccination programmes. Hereby, we analyse positive and negative aspects of the different vaccination strategies.

CONCLUSION

While waiting for the introduction of other antimeningococcal vaccines, covering also for the Group B meningococci, further studies on effectiveness of an optimal schedule to be adopted in European countries are needed.

Methodological concerns with economic evaluations of meningococcal vaccines

The evolution of meningococcal vaccines illustrates nicely the incremental technological process that is common to much medical innovation and particularly appropriate to economic analysis. However, the economic evaluation of vaccines is complicated by several features unique to vaccines, including the possibility of indirect (herd immunity) benefits and the shear breadth of vaccination strategies available to decision makers. As with the vaccines themselves, the modelling approaches applied to the economic evaluation of meningococcal vaccines have evolved to become increasingly complex. Despite such innovation, concerns remain about the quality of economic studies of meningococcal vaccines. This article reviews evaluations of meningococcal vaccine strategies in developed countries and provides recommendations for future work in this area. Four potentially problematic areas in the existing literature are identified - indirect costs, herd immunity, quality of life and comparison programmes - and approaches to these issues are discussed. Recommendations for reporting a 'minimum analysis profile' case are also made. Although comparisons across studies are difficult at best, recent work shows that incorporating the indirect benefits and costs of vaccination substantially improves cost effectiveness.

A dose-range study assessing immunogenicity and safety of one dose of a new candidate meningococcal serogroups A, C, W-135, Y tetanus toxoid conjugate (MenACWY-TT) vaccine administered in the second year of life and in young children

Meningococcal disease incidence is highest in young children, yet a tetravalent conjugate vaccine is currently not available for this age group. This study evaluated a single dose of four different ACWY-TT conjugate vaccine formulations in 240 toddlers (12-14 months) and 268 children (3-5 years) compared to licensed age-appropriate control vaccines. In toddlers, rSBA-MenC GMTs for the selected formulation were statistically higher than after monovalent-MenC-conjugate vaccine. In children, rSBA-GMTs against each serogroup were statistically higher than after tetravalent polysaccharide vaccine. The safety profile was comparable to licensed controls. The new ACWY-TT conjugate vaccine promises high seroprotection levels against meningococcal disease from 1 year of age.

Herd immunity: recent uses in vaccine assessment

Human communities defend themselves against specific infectious agents in a way that extends beyond the simple sum of the immune status of its individuals. By analogy with individual immunity to specific agents, the community level of immunity may vary from complete susceptibility to full protection. Herd immunity has been used to name this community property, which is the result of evolution through natural selection, leading to relationships between two species, typical of prey-predator systems. Varying uses of the term herd immunity led to the use of other expressions, such as herd protection, herd effect and community immunity. Knowledge derived from observational studies and models on herd immunity has supported decisions on the choice of vaccines and vaccination strategies for the benefit of populations. This knowledge is most likely to be extended in the future, with far-reaching effects.

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.

Immunogenicity, reactogenicity and persistence of meningococcal A, C, W-135 and Y-tetanus toxoid candidate conjugate (MenACWY-TT) vaccine formulations in adolescents aged 15-25 years

Development of meningococcal serogroups A, C, W-135 and Y conjugate vaccines could expand coverage against devastating meningococcal diseases. The immunogenicity of one dose of each one of five MenACWY-TT formulations versus a licensed ACWY polysaccharide vaccine was evaluated in 175 healthy subjects of 15-25 years. Serum bactericidal titers (rSBA) were evaluated before and after vaccination. The percentage of rSBA responders to each serogroup A, C, W-135 and Y did not statistically differ from the control for each of the five formulations except for serogroup A that was lower after administration of one formulation. In the 3-year follow-up of the first study where the latter formulation was assessed, bactericidal antibody persistence was similar to the licensed ACWY polysaccharide vaccine for MenA and MenC and higher for MenW-135 and MenY. Our results present five investigational MenACWY-TT conjugate vaccine formulations which are well tolerated and highly immunogenic in adolescents.

Estimating the number needed to vaccinate to prevent diseases and death related to human papillomavirus infection

BACKGROUND

A vaccine against human papillomavirus (HPV) types 6, 11, 16 and 18 is now licensed for use in Canada and many other countries. We sought to estimate the number needed to vaccinate to prevent HPV-related diseases and death.

METHODS

A cohort model of the natural history of HPV infection was developed. Model simulations were based on 209 different parameter sets that reproduced Canadian HPV type-specific data for infection, cervical intraepithelial neoplasia, cervical cancer and genital warts. The number needed to vaccinate was calculated as the number of women who would need to be vaccinated to prevent an HPV-related event during their lifetime.

RESULTS

Among 12-year-old girls, we estimated that the number needed to vaccinate to prevent an episode of genital warts would be 8 (80% credibility interval [CrI] 5-15) and a case of cervical cancer 324 (80% CrI 195-757). These estimates were based on the assumption that the vaccine procures lifelong protection and that its efficacy is 95%. If vaccine protection is assumed to wane at 3% per year, the predicted number needed to vaccinate would increase to 14 (80% CrI 6-18) and 9080 (80% CrI 1040-does not prevent), respectively. The latter number would be greatly reduced with the addition of a booster dose, to 480 (80% CrI 254-1572).

INTERPRETATION

Our model predictions suggest that vaccination with the currently available HPV vaccine may significantly reduce the incidence of genital warts, cervical intraepithelial neoplasia and cervical cancer. However, the benefits (particularly in terms of cervical cancer reduction) are highly dependent on the duration of vaccine protection, on which evidence is currently limited.