Targeted vaccination campaigns of teenagers after two clusters of B invasive meningococcal disease in Brittany, France, 2017

Informing the use of a supplementary immunisation programme for the management of a community cluster of invasive meningococcal disease, Yorkshire, 2022

OBJECTIVES

To outline the management of a community cluster of serogroup B invasive meningococcal disease (IMD) cases, including key factors for decision making and the choice and implementation of control measures.

STUDY DESIGN

Descriptive report of cluster management.

METHODS

Subtyping of IMD cases identified a number of potentially linked cases in a defined geographical area. An Incident Management Team (IMT) was convened to coordinate the public health response. A case definition was developed in order to identify further cases within the cluster.

RESULTS

Four cases of IMD met the case definition and were initially considered as part of this cluster. Three resided in the same small town, which was the focus for public health management. The IMT agreed that it would be proportionate to instigate additional control measures. The population at higher risk of infection were identified, and a supplementary vaccination programme was rolled out in the community. Over five clinics, 45.6% (639/1401) of the target cohort received at least one dose of the vaccine, with 34.7% (486/1401) receiving both doses. Inequalities in uptake were observed by sex, age and deprivation.

CONCLUSIONS

Decision making for public health responses to IMD clusters is complex. Informed by epidemiological evidence, numerous partners engaged in collaborative decision making, which was critical for the effective implementation of the community response. Links between the local authority public health team and the community enabled the use of existing structures and relationships to maximise the number of vaccinations delivered. No further cases of IMD linked to this cluster were identified.

Meningococcal B Immunisation in Adults and Potential Broader Immunisation Strategies: A Narrative Review

Recombinant vaccines against invasive meningococcal disease due to Neisseria meningitidis serogroup B (MenB) have shown substantial impact in reducing MenB disease in targeted populations. 4CMenB targets four key N. meningitidis protein antigens; human factor H binding protein (fHbp), Neisserial heparin binding antigen (NHBA), Neisseria adhesin A (NadA) and the porin A protein (PorA P1.4), with one or more of these expressed by most pathogenic MenB strains, while MenB-FHbp targets two distinct fHbp variants. While many countries recommend MenB immunisation in adults considered at high risk due to underlying medical conditions or immunosuppression, there are no recommendations for routine use in the general adult population. We reviewed the burden of MenB in adults, where, while incidence rates remain low (and far lower than in young children < 5 years of age at greatest risk), a substantial proportion of MenB cases (20% or more) is now observed in the adult population; evident in Europe, Australia, and in the United States. We also reviewed immunogenicity data in adults from clinical studies conducted during MenB vaccine development and subsequent post-licensure studies. A 2-dose schedule of 4CMenB generates hSBA titres ≥ 1:4 towards all four key vaccine target antigens in up to 98-100% of subjects. For MenB-FHbp, a ≥ fourfold rise in hSBA titres against the four primary representative test strains was observed in 70-95% of recipients following a 3-dose schedule. While this suggests potential benefits for MenB immunisation if used in adult populations, data are limited (especially for adults > 50 years) and key aspects relating to duration of protection remain unclear. Although a broader adult MenB immunisation policy could provide greater protection of the adult population, additional data are required to support policy decision-making.

An adenoviral-vectored vaccine confers seroprotection against capsular group B meningococcal disease

Adenoviral-vectored vaccines are licensed for prevention of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Ebola virus, but, for bacterial proteins, expression in a eukaryotic cell may affect the antigen's localization and conformation or lead to unwanted glycosylation. Here, we investigated the potential use of an adenoviral-vectored vaccine platform for capsular group B meningococcus (MenB). Vector-based candidate vaccines expressing MenB antigen factor H binding protein (fHbp) were generated, and immunogenicity was assessed in mouse models, including the functional antibody response by serum bactericidal assay (SBA) using human complement. All adenovirus-based vaccine candidates induced high antigen-specific antibody and T cell responses. A single dose induced functional serum bactericidal responses with titers superior or equal to those induced by two doses of protein-based comparators, as well as longer persistence and a similar breadth. The fHbp transgene was further optimized for human use by incorporating a mutation abrogating binding to the human complement inhibitor factor H. The resulting vaccine candidate induced high and persistent SBA responses in transgenic mice expressing human factor H. The optimized transgene was inserted into the clinically relevant ChAdOx1 backbone, and this vaccine has now progressed to clinical development. The results of this preclinical vaccine development study underline the potential of vaccines based on genetic material to induce functional antibody responses against bacterial outer membrane proteins.

Epidemiology and Clinical Burden of Meningococcal Disease in France: Scoping Review

Invasive meningococcal disease (IMD) remains a significant health concern due to its unpredictable nature and its rapid progression. Even if occurrence of IMD is strictly monitored by a national surveillance network, no information on long-term sequelae is reported, making it difficult to assess the entire clinical burden of IMD in France. The aim of this scoping review was to analyze the epidemiology and the clinical burden of IMD in France by reporting the main epidemiological parameters, and by describing the clinical consequences and the care pathway of patients. The process of the review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension to the Scoping Reviews guidelines. In France, the incidence of IMD cases has been fluctuating over time, characterized by an overall downward trend linked to a decrease in Sg B cases and the introduction of mandatory vaccination against Sg C. Sg W cases increased in recent years (from 5% to 21% in 2019). The case fatality rate remained constant (6-12.9%). The most frequently reported sequelae were severe neurological disorder, epilepsy, and anxiety. However, data on sequelae and care pathways were scarce. Further research should concentrate on providing robust identification of sequelae and the subsequent impact on quality of life, as well as on the organization of optimal care and support for patients and their families.

Meningococcal Disease Outbreaks: A Moving Target and a Case for Routine Preventative Vaccination

Outbreaks of invasive meningococcal disease (IMD) are unpredictable, can be sudden and have devastating consequences. We conducted a non-systematic review of the literature in PubMed (1997-2020) to assess outbreak response strategies and the impact of vaccine interventions. Since 1997, IMD outbreaks due to serogroups A, B, C, W, Y and X have occurred globally. Reactive emergency mass vaccination campaigns have encompassed single institutions (schools, universities) through to whole sections of the population at regional/national levels (e.g. serogroup B outbreaks in Saguenay-Lac-Saint-Jean region, Canada and New Zealand). Emergency vaccination responses to IMD outbreaks consistently incurred substantial costs (expenditure on vaccine supplies, personnel costs and interruption of other programmes). Impediments included the limited pace of transmission of information to parents/communities/healthcare workers; issues around collection of informed consents; poor vaccine uptake by older adolescents/young adults, often a target age group; issues of reimbursement, particularly in the USA; and difficulties in swift supply of large quantities of vaccines. For serogroup B outbreaks, the need for two doses was a significant issue that contributed substantially to costs, delayed onset of protection and non-compliance with dose 2. Real-world descriptions of outbreak control strategies and the associated challenges systematically show that reactive outbreak management is administratively, logistically and financially costly, and that its impact can be difficult to measure. In view of the unpredictability, fast pace and potential lethality of outbreak-associated IMD, prevention through routine vaccination appears the most effective mitigation tool. Highly effective vaccines covering five of six disease-causing serogroups are available. Preparedness through routine vaccination programmes will enhance the speed and effectiveness of outbreak responses, should they be needed (ready access to vaccines and need for a single booster dose rather than a primary series).

Recent advances in meningococcal B disease prevention: real-world evidence from 4CMenB vaccination

OBJECTIVES

4CMenB is a broadly protective vaccine against invasive meningococcal capsular group B disease (MenB IMD). Licensed worldwide based on immunogenicity and safety data, effectiveness and impact data are now available. We comprehensively reviewed all available real-world evidence gathered from use of 4CMenB since licensure.

RESULTS

Data from 7 countries provide evidence of effectiveness and impact across different healthcare settings and age-groups, including national/regional immunization programs, observational studies and outbreak control. At least 2 4CMenB doses reduced MenB IMD by 50%-100% in 2-month to 20-year-olds depending on length of follow-up. Estimates of vaccine effectiveness in fully vaccinated cohorts ranged from 59%-100%. The safety profile of 4CMenB administered in real-world settings was consistent with pre-licensure clinical trial data.

CONCLUSION

MenB IMD is an uncommon but life-threatening disease with unpredictable epidemiology. The substantial body of data demonstrating 4CMenB effectiveness and impact supports its use in IMD prevention. The results reinforce the importance of direct protection of the highest risk groups; infants/young children and adolescents. Direct protection via routine infant immunization with catch-up in young children and routine adolescent vaccination could be the preferred option for MenB disease control. A Video Abstract linked to this article is available on Figshare: https://doi.org/10.6084/m9.figshare.14546790.