Modelling the impact of 4CMenB and MenACWY meningococcal combined vaccination strategies including potential 4CMenB cross-protection: An application to England

Public Health Impact and Cost-Effectiveness Analysis of 4-Component Meningococcal Serotype B Vaccination for Infants in France

BACKGROUND AND OBJECTIVES

In France, meningococcal serogroup B (MenB) is the most common serogroup causing invasive meningococcal disease (IMD) in infants and young children. Our objective was to illustrate the impact of model choices on health outcomes and the cost-effectiveness of infant vaccination with the multicomponent meningococcal serogroup B vaccine (4CMenB) versus no vaccine in France.

METHODS

A previously published dynamic transmission-based cost-effectiveness model was adapted for the French context using updated, French-specific demographic, epidemiological, and cost data. IMD incidence and long-term sequelae were derived through analysis of French healthcare and surveillance databases. A collective perspective over a 100-year time horizon was adopted, with a discount rate of 2.5%, reduced to 1.5% after the first 30 years. Deterministic and probabilistic sensitivity and scenario analyses were performed.

RESULTS

In the base case analysis, infant vaccination with 4CMenB avoided 3101 MenB IMD cases in infants aged < 1 year (- 54%) and 6845 cases in all age groups (- 21%). The estimated incremental cost-effectiveness ratio was €316,272/quality-adjusted life-year (QALY) but was highly sensitive to the types of sequelae included, MenB incidence, vaccine effectiveness parameters, and consideration of life-expectancy in IMD survivors (range: €65,272/QALY to €493,218/QALY).

CONCLUSIONS

Using economic models compliant with French methodology guidelines, 4CMenB does not seem cost-effective; however, results are sensitive to model choices and 4CMenB immunization is an effective strategy to prevent MenB IMD cases and to improve quality of life and economic burden associated with MenB IMD treatment, especially with regard to long-term sequelae.

Modelling the Public Health Impact of MenACWY and MenC Adolescent Vaccination Strategies in Germany

INTRODUCTION

Invasive meningococcal disease (IMD) causes significant mortality and long-term sequelae. This study assesses the potential public health impact of adolescent vaccination strategies employing MenACWY and MenC vaccines in Germany, where the existing meningococcal immunisation programme predominantly involves MenC administration in toddlers.

METHODS

A dynamic transmission model was developed to simulate the carriage of five meningococcal serogroup compartments (AY/B/C/W/Other) from 2019 until 2060 within 1-year age groups from 0 to 99 years of age. IMD cases were estimated based on case-carrier ratios. The model considered vaccine effectiveness against carriage acquisition and IMD.

RESULTS

The model predicts that introducing MenACWY adolescent vaccination could lead to a considerable reduction in IMD incidence, with the potential to prevent up to 65 cases per year and a cumulative total of 1467 cases by 2060. This decrease, mainly driven by herd effects, would result in a reduction of IMD incidence across all age groups, regardless of vaccination age. Furthermore, implementing MenACWY vaccination in adolescents is projected to decrease annual MenACWY-related IMD mortality by up to 64%, equating to an overall prevention of 156 IMD deaths by 2060. These protective outcomes are expected to culminate in approximately 2250 life years gained (LYG) throughout the model's projected time horizon. In contrast, the adoption of MenC vaccination in adolescents is predicted to have minimal influence on both IMD incidence and mortality, as well as on LYG.

CONCLUSION

The results of this study demonstrate that implementing MenACWY vaccination for adolescents in Germany is likely to notably reduce IMD incidence and mortality across age groups. However, the introduction of MenC adolescent vaccination shows only limited impact. Considering the extensive healthcare resources typically required for IMD management, these findings suggest the potential for economic benefits associated with the adoption of MenACWY adolescent vaccination, warranting further cost-effectiveness analysis.

Assessing the Role of Infant and Toddler MenACWY Immunisation in the UK: Does the Adolescent MenACWY Programme Provide Sufficient Protection?

A combined Haemophilus influenzae type b (Hib)/meningococcal serogroup C (MenC) vaccine will soon be unavailable in the UK immunisation schedule due to discontinuation by the manufacturer. An interim statement by the Joint Committee on Vaccination and Immunisation (JCVI) advises stopping MenC immunisation at 12 months of age when this occurs. We undertook an analysis of the public health impact of various potential meningococcal vaccination strategies in the UK in the absence of the Hib/MenC vaccine. A static population-cohort model was developed evaluating the burden of IMD (using 2005-2015 epidemiological data) and related health outcomes (e.g., cases, cases with long-term sequelae, deaths), which allows for the comparison of any two meningococcal immunisation strategies. We compared potential strategies that included different combinations of infant and/or toddler MenACWY immunisations with the anticipated future situation in which a 12-month MenC vaccine is not used, but the MenACWY vaccine is routinely given in adolescents. The most effective strategy is combining MenACWY immunisation at 2, 4, and 12 months of age with the incumbent adolescent MenACWY immunisation programme, resulting in the prevention of an additional 269 IMD cases and 13 fatalities over the modelling period; of these cases, 87 would be associated with long-term sequelae. Among the different vaccination strategies, it was observed that those with multiple doses and earlier doses provided the greatest protection. Our study provides evidence suggesting that the removal of the MenC toddler immunisation from the UK schedule would potentially increase the risk of unnecessary IMD cases and have a detrimental public health impact if not replaced by an alternate infant and/or toddler programme. This analysis supports that infant and toddler MenACWY immunisation can provide maximal protection while complementing both infant/toddler MenB and adolescent MenACWY immunisation programmes in the UK.

Public health perspective of a pentavalent meningococcal vaccine combining antigens of MenACWY-CRM and 4CMenB

OBJECTIVES

Invasive meningococcal disease (IMD) is a life-threatening disease that can rapidly progress to death or leave survivors with severe, life-long sequelae. Five meningococcal serogroups (A, B, C, W and Y) account for nearly all IMD. Meningococcal serogroup distribution fluctuates over time across the world and age groups. Here, we consider the potential public health impact of a pentavalent MenABCWY vaccine developed to help further control meningococcal disease and improve immunisation rates.

RESULTS

The GSK MenABCWY vaccine combines the antigenic components of MenACWY-CRM (Menveo®) and 4CMenB (Bexsero®), building on a wide body of clinical experience and real-world evidence. Both approved vaccines have acceptable safety profiles, demonstrate immunogenicity, and are broadly used, including in national immunisation programmes in several countries. Since the advent of quadrivalent vaccines, public health in relation to IMD has improved, with a decline in the overall incidence of IMD and an increase in vaccine coverage.

CONCLUSION

A pentavalent MenABCWY has the potential to provide further public health benefits through practical, broad IMD protection programmes encompassing serogroups A, B, C, W and Y, and is currently in late-stage development.

A re-assessment of 4CMenB vaccine effectiveness against serogroup B invasive meningococcal disease in England based on an incidence model

BACKGROUND

The four-component serogroup B meningococcal 4CMenB vaccine (Bexsero, GSK) has been routinely given to all infants in the United Kingdom at 2, 4 and 12 months of age since September 2015. After 3 years, Public Health England (PHE) reported a 75% [95% confidence interval 64%; 81%] reduction in the incidence of serogroup B invasive meningococcal disease (IMD) in age groups eligible to be fully vaccinated. In contrast, vaccine effectiveness (VE) evaluated in the same immunization program applying the screening method was not statistically significant. We re-analyzed the data using an incidence model.

METHODS

Aggregate data-stratified by age, year and doses received-were provided by PHE: serogroup B IMD case counts for the entire population of England (years 2011-2018) and 4CMenB vaccine uptake in infants. We combined uptake with national population estimates to obtain counts of vaccinated and unvaccinated person-time by age and time. We re-estimated VE comparing incidence rates in vaccinated and non-vaccinated subjects using a Bayesian Poisson model for case counts with person-time data as an offset. The model was adjusted for age, time and number of doses received.

RESULTS

The incidence model showed that cases decreased until 2013-2014, followed by an increasing trend that continued in the non-vaccinated population during the immunization program. VE in fully vaccinated subjects (three doses) was 80.1% [95% Bayesian credible interval (BCI): 70.3%; 86.7%]. After a single dose, VE was 33.5% [12.4%; 49.7%]95%BCI and after two doses, 78.7% [71.5%; 84.5%]95%BCI. We estimated that vaccination averted 312 cases [252; 368]95%BCI between 2015 and 2018. VE was in line with the previously reported incidence reduction.

CONCLUSIONS

Our estimates of VE had higher precision than previous estimates based on the screening method, which were statistically not significant, and in line with the 75% incidence reduction previously reported by PHE. When disease incidence is low and vaccine uptake is high, the screening method applied to cases exclusively from the population eligible for vaccination may not be precise enough and may produce misleading point-estimates. Precise and accurate VE estimates are fundamental to inform public health decision making. VE assessment can be enhanced using models that leverage data on subjects not eligible for vaccination.

Modeling the public health impact of different meningococcal vaccination strategies with 4CMenB and MenACWY versus the current toddler MenACWY National Immunization Program in Chile

Invasive meningococcal disease (IMD) is an uncommon yet unpredictable, severe, and life-threatening disease with the highest burden in young children. In Chile, most IMD is caused by meningococcal serogroup B (MenB) and W (MenW) infection. In response to a MenW outbreak in 2012, a toddler vaccination program was implemented using quadrivalent meningococcal conjugate vaccine against serogroups A, C, W and Y (MenACWY). The vaccine program, however, does not protect infants or other unvaccinated age groups and does not protect against MenB IMD. Since 2017, MenB IMD cases are becoming increasingly prevalent. Using a dynamic transmission model adapted for Chile, this analysis assessed the public health impact (reduction in IMD cases, long-term sequelae, deaths, and quality-adjusted life-years) of six alternative vaccination strategies using MenACWY and/or the four-component MenB (4CMenB) vaccine in infants, toddlers, and/or adolescents compared to the National Immunization Program (NIP) implemented in 2014. Strategies that added infant 4CMenB to MenACWY in toddlers or adolescents would prevent more IMD than the current NIP, observed within the first 5 years of the program. Replacing the NIP by an adolescent MenACWY strategy would prevent more IMD in the longer term, once herd immunity is established to protect unvaccinated infants or older age groups. The strategy that maximized reduction of IMD cases and associated sequelae in all age groups with immediate plus long-term benefits included infant 4CMenB and MenACWY in both toddlers and adolescents. This analysis can help policymakers determine the best strategy to control IMD in Chile and improve public health. A set of audio slides linked to this manuscript can be found at https://doi.org/10.6084/m9.figshare.16837543.

What is the context?

Invasive meningococcal disease (IMD) is a severe, sometimes fatal, unpredictable disease with highest rates in infants, young children, and adolescents. It is caused by different serogroups of Neisseria meningitidis bacteria. Most cases in Chile are due to meningococcal serogroups B (MenB) and W (MenW). Following a MenW IMD outbreak in 2012, vaccination was introduced, leading to the current National Immunization Program (NIP) in toddlers with quadrivalent meningococcal conjugate vaccine (MenACWY) (protecting against IMD caused by MenA, C, W, and Y).

What is new?

A disease model to predict the impact of vaccination strategies in the Chilean population compared six alternative strategies, using the multi-component MenB (4CMenB) vaccine for infants (protecting against MenB, with potential cross-protection against MenW and Y IMD) and/or the MenACWY vaccine for toddlers and/or adolescents.

What is the impact?

Results, compared to the NIP, show that: Strategy 1 (a program targeting only infants with 4CMenB) would reduce more MenB cases but fewer MenA, C, W and Y cases resulting in a lower reduction of total IMD cases in the long term; Strategy 3 (a program targeting only adolescents with MenACWY) would have a similar effect to the NIP in the short term but a far greater IMD reduction in the long term (as vaccinating this age group eventually reduces transmission to other age groups, reducing their risk of disease); all the other strategies targeted more than one age group, further reducing numbers of IMD cases compared with the NIP. The greatest benefits were seen with infant 4CMenB vaccination combined with toddler and adolescent MenACWY vaccination. Results can help policymakers determine the best IMD strategy to maximize the benefits of available meningococcal vaccines.

4CMenB vaccine and its role in preventing transmission and inducing herd immunity

INTRODUCTION

: Vaccination is the most effective method of protecting people from invasive meningococcal disease (IMD). Of all the capsular groups, B is the most common cause of invasive meningococcal disease in many parts of the world. Despite this, adolescent meningococcal B vaccine programs have not been implemented globally, partly due to the lack of evidence for herd immunity afforded by meningococcal B vaccines.

AREAS COVERED

This review aims to synthesise the available evidence on recombinant 4CMenB vaccines' ability to reduce pharyngeal carriage and therefore provide indirect (herd) immunity against IMD.

EXPERT OPINION

There is some evidence that the 4CMenB vaccine may induce cross-protection against non-B carriage of meningococci. However, the overall body of evidence does not support a clinically significant reduction in carriage of disease-associated or group B meningococci following 4CMenB vaccination. No additional cost-benefit from herd immunity effects should be included when modelling the cost-effectiveness of 4CMenB vaccine programs against group B IMD. 4CMenB immunisation programs should focus on direct (individual) protection for groups at greatest risk of meningococcal disease.

Future meningococcal B and combination vaccines being developed should consider the impact of the vaccine on carriage as part of their clinical evaluation.

Evolving strategies for meningococcal vaccination in Europe: Overview and key determinants for current and future considerations

Invasive meningococcal disease (IMD) is a life-threatening, unpredictable condition. Vaccines are available against 5 of the 6 meningococcal serogroups (Men) accounting for nearly all IMD cases worldwide; conjugate monovalent MenC, quadrivalent MenACWY, and protein-based MenB vaccines are commonly used. We provide a comprehensive overview of the evolution of meningococcal vaccination strategies employed in national immunization programmes (NIPs) and their impact on IMD incidence in Europe. A more in-depth description is given for several countries: the United Kingdom (UK), the Netherlands, Greece, Italy, and Ireland. We searched European health authorities' websites and PubMed. Various vaccines and immunization schedules are used in 21 NIPs. Most countries implement MenC vaccination in infants, MenACWY in adolescents, and a growing number, MenB in infants. Only Malta has introduced MenACWY vaccination in infants, and several countries reimburse immunization of toddlers. The UK, Italy, Ireland, Malta, Andorra, and San Marino recommend MenB vaccination in infants and MenACWY vaccination in adolescents, targeting the most prevalent serogroups in the most impacted age groups. Main factors determining new vaccination strategies are fluctuating IMD epidemiology, ease of vaccine implementation, ability to induce herd protection, favorable benefit-risk balance, and acceptable cost-effectiveness. Since 1999, when the UK introduced MenC vaccination, the reduction in IMD incidence has been gradually enhanced as other countries adopted routine meningococcal vaccinations. Meningococcal vaccination strategies in each country are continually adapted to regional epidemiology and national healthcare priorities. Future strategies may include broader coverage vaccines when available (e.g., MenABCWY, MenACWY), depending on prevailing epidemiology.

Cost-Effectiveness of 4CMenB Infant Vaccination in England: A Comprehensive Valuation Considering the Broad Impact of Serogroup B Invasive Meningococcal Disease

OBJECTIVES

This cost-effectiveness analysis (CEA) of 4CMenB infant vaccination in England comprehensively considers the broad burden of serogroup B invasive meningococcal disease (MenB IMD), which has not been considered, or was only partially considered in previous CEAs.

METHODS

A review of previous MenB vaccination CEAs was conducted to identify aspects considered in the evaluation of costs and health outcomes of the disease burden of MenB IMD. To inform the model structure and comprehensive analysis, the aspects were grouped into 5 categories. A stepwise analysis was conducted to analyze the impact of each category, and the more comprehensive consideration of disease burden, on the incremental cost-effectiveness ratio (ICER).

RESULTS

MenB IMD incidence decreased by 46.0% in infants and children 0-4 years old within 5 years after introduction of the program. Stepwise inclusion of the 5 disease burden categories to a conventional narrow CEA setting reduced the ICER from £360 595 to £18 645-that is, considering the impact of all 5 categories, 4CMenB infant vaccination is cost-effective at a threshold of £20 000 per QALY gained.

CONCLUSIONS

When considering comprehensively the MenB IMD burden, 4CMenB infant vaccination can be cost-effective, a finding contrary to previous CEAs. This analysis allows policy decision-makers globally to infer the impact of current disease burden considerations on the cost-effectiveness and the comprehensive assessment necessary for MenB IMD. Although this comprehensive CEA can help inform decision making today, it may be limited in capturing the full disease burden and complex interactions of health and economics of MenB IMD.

Why the Anti-Meningococcal B Vaccination during Adolescence Should Be Implemented in Italy: An Overview of Available Evidence

Although meningococcal disease has a low incidence in Italy, it is a public health concern owing to its high lethality rate and high frequency of transitory and/or permanent sequelae among survivors. The highest incidence rates are recorded in infants, children and adolescents, and most of the cases are due to Neisseria meningitidis B. In Italy, anti-meningococcal B (anti-MenB) vaccination is free for infants but, despite the considerable disease burden in adolescents, no national recommendation to vaccinate in this age-group is currently available. The aim of this study was to assess the main available scientific evidence to support the Italian health authorities in implementing a program of free anti-MenB vaccination for adolescents. We conducted an overview of the scientific literature on epidemiology, disease burden, immunogenicity and safety of available vaccines, and economic evaluations of vaccination strategies. Each case of invasive meningococcal disease generates a considerable health burden (lethality rate: 9%; up to 60% of patients experience at least one sequela) in terms of impaired quality of life for survivors and high direct and indirect costs (the mean overall cost of acute phase for a single case amounts to about EUR 13,952; the costs for post-acute and the long-term phases may vary widely depending of the type of sequela, reaching an annual cost of about EUR 100,000 in cases of severe neurological damage). Furthermore, vaccination against meningococcus B in adolescence proved cost-effective. The study highlights the need to actively offer the anti-MenB vaccination during adolescence at a national level. This would make it possible to avoid premature deaths and reduce the high costs borne by the National Health Service and by society of supporting survivors who suffer temporary and/or permanent sequelae.