Persistence of bactericidal antibodies following early infant vaccination with a serogroup B meningococcal vaccine and immunogenicity of a preschool booster dose

Recent advances in various bio-applications of bacteria-derived outer membrane vesicles

Outer membrane vesicles (OMVs) are spherical nanoparticles released from gram-negative bacteria. OMVs were originally classified into native 'nOMVs' (produced naturally from budding of bacteria) and non-native (produced by mechanical means). nOMVs and detergent (dOMVs) are isolated from cell supernatant without any detergent cell disruption techniques and through detergent extraction, respectively. Growth stages and conditions e.g. different stress factors, including temperature, nutrition deficiency, and exposure to hazardous chemical agents can affect the yield of OMVs production and OMVs content. Because of the presence of bacterial antigens, pathogen-associated molecular patterns (PAMPs), various proteins and the vesicle structure, OMVs have been developed in many biomedical applications. OMVs due to their size can be phagocytized by APCs, enter lymph vessels, transport antigens efficiently, and induce both T and B cells immune responses. Non-engineered OMVs have been frequently used as vaccines against different bacterial and viral infections, and various cancers. OMVs can also be used in combination with different antigens as an attractive vaccine adjuvant. Indeed, foreign antigens from target microorganisms can be trapped in the lumen of nonpathogenic vesicles or can be displayed on the surface through bacterial membrane protein to increase the immunogenicity of the antigens. In this review, different factors affecting OMV production including time of cultivation, growth media, stress conditions and genetic manipulations to enhance vesiculation will be described. Furthermore, recent advances in various biological applications of OMVs such as vaccine, drug delivery, cancer therapy, and enzyme carrier are discussed. Generally, the application of OMVs as vaccine carrier in three categories (i.e., non-engineered OMVs, OMVs as an adjuvant, recombinant OMVs (rOMVs)), as delivery system for small interfering RNA and therapeutic agents, and as enzymes carrier will be discussed.

Invasive Meningococcal Disease epidemiology and vaccination strategies in four Southern European countries: a review of the available data

INTRODUCTION

Invasive meningococcal disease (IMD) is a major health concern which can be prevented through vaccination. Conjugate vaccines against serogroups A, C, W and Y and two protein-based vaccines against serogroup B are currently available in the European Union.

AREAS COVERED

We present epidemiologic data for Italy, Portugal, Greece and Spain using publicly available reports from national reference laboratories and national or regional immunization programs (1999-2019), aiming to confirm risk groups, and describe time trends in overall incidence and serogroup distribution, as well as impact of immunization. Analysis of circulating MenB isolates in terms of the surface factor H binding protein (fHbp) using PubMLST is discussed as fHbp represents an important MenB vaccine antigen. Predictions of potential reactivity of the two available MenB vaccines (MenB-fHbp and 4CMenB) with circulating MenB isolates are also provided as assessed using the recently developed MenDeVAR tool.

EXPERT OPINION

Understanding dynamics of IMD and continued genomic surveillance are essential for evaluating vaccine effectiveness, but also prompting proactive immunization programs to prevent future outbreaks. Importantly, the successful design of further effective meningococcal vaccines to fight IMD relies on considering the unpredictable epidemiology of the disease and combining lessons learnt from capsule polysaccharide vaccines and protein-based vaccines.

Effectiveness of a Meningococcal Group B Vaccine (4CMenB) in Children

BACKGROUND

In September 2015, the four-component, protein-based meningococcal serogroup B vaccine (4CMenB; Bexsero) became available for private purchase in Spain.

METHODS

We conducted a nationwide matched case-control study to assess the effectiveness of 4CMenB in preventing invasive meningococcal disease in children. The study included all laboratory-confirmed cases of invasive meningococcal disease in children younger than 60 months of age between October 5, 2015, and October 6, 2019, in Spain. Each case patient was matched with four controls according to date of birth and province. 4CMenB vaccination status of the case patients and controls was compared with the use of multivariate conditional logistic regression.

RESULTS

We compared 306 case patients (243 [79.4%] with serogroup B disease) with 1224 controls. A total of 35 case patients (11.4%) and 298 controls (24.3%) had received at least one dose of 4CMenB. The effectiveness of complete vaccination with 4CMenB (defined as receipt of at least 2 doses, administered in accordance with the manufacturer's recommendations) was 76% (95% confidence interval [CI], 57 to 87) against invasive meningococcal disease caused by any serogroup, and partial vaccination was 54% (95% CI, 18 to 74) effective. Complete vaccination resulted in an effectiveness of 71% (95% CI, 45 to 85) against meningococcal serogroup B disease. Vaccine effectiveness with at least one dose of 4CMenB was 64% (95% CI, 41 to 78) against serogroup B disease and 82% (95% CI, 21 to 96) against non-serogroup B disease. With the use of the genetic Meningococcal Antigen Typing System, serogroup B strains that were expected to be covered by 4CMenB were detected in 44 case patients, none of whom had been vaccinated.

CONCLUSIONS

Complete vaccination with 4CMenB was found to be effective in preventing invasive disease by serogroup B and non-serogroup B meningococci in children younger than 5 years of age.

Inclusion of a dual signal sequence enhances the immunogenicity of a novel viral vectored vaccine against the capsular group B meningococcus

BACKGROUND

Disease caused by the capsular group B meningococcus (MenB) is the leading cause of infectious death in UK infants. A novel adenovirus-based vaccine encoding the MenB factor H binding protein (fHbp) with an N-terminal dual signal sequence induces high titres of protective antibody after a single dose in mice. A panel of N-terminal signal sequence variants were created to assess the contribution of components of this sequence to transgene expression kinetics of the encoded antigen from mammalian cells and the resultant effect on immunogenicity of fHbp.

RESULTS

The full-length signal sequence (FL SS) resulted in superior early antigen expression compared with the panel of variants, as measured by flow cytometry and confocal imaging, and supported higher bactericidal antibody levels against the expressed antigen in mouse sera < 6 weeks post-immunisation than the licensed four component MenB vaccine. The FL SS also significantly increased antigen-specific T cell responses against other adenovirus-encoded bacterial antigens in mice.

CONCLUSIONS

These findings demonstrate that the FL SS enhances immunogenicity of the encoded antigen, supporting its inclusion in other viral vectored bacterial antigen transgenes.

Immunogenicity of a single 4CMenB vaccine booster in adolescents 11 years after childhood immunisation

The clinical development of the meningococcal vaccine, 4CMenB, included 2 doses in vaccine-naïve adolescents, which was considered unlikely to be cost-effective for implementation. Theoretically, priming with 4CMenB in early childhood might drive strong immune responses after only a single booster dose in adolescents and reduce programmatic costs. To address this question, children over 11 years old who took part in previous trials involving the administration of 3-5 doses of 4CMenB at infant/preschool age from 2006 were recruited into a post licensure single-centre trial, and were divided into two groups: those who received their last dose at 12 months old (infant group) and those who received their last dose at 3 years old (infant + preschool group). Naïve age-matched controls were randomised to receive one (adolescent 1 group) or two doses at days 0 and 28 (adolescent 2 group) of 4CMenB. Serum bactericidal antibody (SBA) assays using human complement were performed against three reference strains prior to vaccination, and at 1, 6 and 12 months. Previous vaccination was associated with a higher response to a single booster dose at 11 years of age, one-month post-vaccination, when compared with a single dose in naïve age-matched controls. At day 180, the highest responses were observed in participants in the infant + preschool group against strain 5/99 (GMT 316.1 [CI 158.4 to 630.8]), as compared with naïve adolescents who received two doses (GMTs 84.5 [CI 57.7 to 123.6]). When the last dose was received at 12-months of age, responses to a single adolescent dose were not as robust (GMT 61.1 [CI 14.8 to 252.4] to strain 5/99). This descriptive study indicates that the highest SBA responses after a single dose in adolescence were observed in participants who received a preschool dose, suggesting that B cell memory responses are not sufficiently primed at less than 12 months of age. Trial registration EudraCT 2017-004732-11, ISRCTN16774163.

Product review on the IMD serogroup B vaccine Bexsero®

Bexsero® is a multicomponent vaccine composed of four major proteins of Neisseria meningitidis: the fHbp, NHBA, NadA and PorA. This vaccine was licensed against invasive meningococcal disease (IMD) due to serogroup B isolates. When administered alone, Bexsero® showed a safety profile similar to other childhood vaccines. It provides an excellent immunogenicity but that requires booster doses in infants and young children. Although the vaccine does not seem to impact on acquisition of carriage of serogroup B isolates, it confers protection against isolates of serogroup B harboring distinct but cross-reactive variants of fHbp, NadA and NHBA. Primary vaccination schemes in infancy underwent a rapid increase after a toddler booster suggesting an anamnestic response and the establishment of a memory response. As Bexsero® targets sub-capsular proteins that can be conserved regardless the capsule, the vaccine can be effective against non-B isolates such as isolates of serogroups W and X.

Human B Cell Responses to Dominant and Subdominant Antigens Induced by a Meningococcal Outer Membrane Vesicle Vaccine in a Phase I Trial

Neisseria meningitidis outer membrane vesicle (OMV) vaccines are safe and provide strain-specific protection against invasive meningococcal disease (IMD) primarily by inducing serum bactericidal antibodies against the outer membrane proteins (OMP). To design broader coverage vaccines, knowledge of the immunogenicity of all the antigens contained in OMVs is needed. In a Phase I clinical trial, an investigational meningococcal OMV vaccine, MenPF1, made from a meningococcus genetically modified to constitutively express the iron-regulated FetA induced bactericidal responses to both the PorA and the FetA antigen present in the OMP. Using peripheral blood mononuclear cells collected from this trial, we analyzed the kinetics of and relationships between IgG, IgA, and IgM B cell responses against recombinant PorA and FetA, including (i) antibody-secreting cells, (ii) memory B cells, and (iii) functional antibody responses (opsonophagocytic and bactericidal activities). Following MenPF1vaccination, PorA-specific IgG secreting cell responses were detected in up to 77% of participants and FetA-specific responses in up to 36%. Memory B cell responses to the vaccine were low or absent and mainly detected in participants who had evidence of preexisting immunity (P = 0.0069). Similarly, FetA-specific antibody titers and bactericidal activity increased in participants with preexisting immunity and is consistent with the idea that immune responses are elicited to minor antigens during asymptomatic Neisseria carriage, which can be boosted by OMV vaccines.

IMPORTANCENeisseria meningitidis outer membrane vesicles (OMV) are a component of the capsular group B meningococcal vaccine 4CMenB (Bexsero) and have been shown to induce 30% efficacy against gonococcal infection. They are composed of multiple antigens and are considered an interesting delivery platform for vaccines against several bacterial diseases. However, the protective antibody response after two or three doses of OMV-based meningococcal vaccines appears short-lived. We explored the B cell response induced to a dominant and a subdominant antigen in a meningococcal OMV vaccine in a clinical trial and showed that immune responses are elicited to minor antigens. However, memory B cell responses to the OMV were low or absent and mainly detected in participants who had evidence of preexisting immunity against the antigens. Failure to induce a strong B cell response may be linked with the low persistence of protective responses.

Bioengineering Strategies for Developing Vaccines against Respiratory Viral Diseases

Respiratory viral pathogens like influenza and coronaviruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have caused outbreaks leading to millions of deaths. Vaccinations are, to date, the best and most economical way to control such outbreaks and have been highly successful for several pathogens. Currently used vaccines for respiratory viral pathogens are primarily live attenuated or inactivated and can risk reversion to virulence or confer inadequate immunity. The recent trend of using potent biomolecules like DNA, RNA, and protein antigenic components to synthesize vaccines for diseases has shown promising results. Still, it remains challenging to translate due to their high susceptibility to degradation during storage and after delivery. Advances in bioengineering technology for vaccine design have made it possible to control the physicochemical properties of the vaccines for rapid synthesis, heightened antigen presentation, safer formulations, and more robust immunogenicity. Bioengineering techniques and materials have been used to synthesize several potent vaccines, approved or in trials, against coronavirus disease 2019 (COVID-19) and are being explored for influenza, SARS, and Middle East respiratory syndrome (MERS) vaccines as well. Here, we review bioengineering strategies such as the use of polymeric particles, liposomes, and virus-like particles in vaccine development against influenza and coronaviruses and the feasibility of adopting these technologies for clinical use.

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.

Economic evaluation of meningococcal serogroup B (MenB) vaccines: A systematic review

BACKGROUND

Meningococcal serogroup B (MenB) has emerged as the leading cause of invasive meningococcal disease (IMD) in several countries following the release of effective vaccines against serogroups A, C, W, and Y. In 2013, however, the first multicomponent MenB vaccine (Bexsero®) was licensed in Europe.

AIM

To review the evidence on the cost-effectiveness of vaccination against MenB.

METHODS

Searches were performed in MEDLINE, EMBASE, Web of Science, NHS EED, Econlit, Tufts CEA registry, and HTA. Three reviewers independently screened and selected studies. Using a narrative synthesis, studies were categorized by vaccination strategies. The quality of included studies was assessed using the Comparative Health Economics Evaluation Reporting Standards (CHEERS) checklist.

RESULTS

13 studies were included. Ten studies were conducted in the European region and three in the Americas. None of the vaccination strategies were considered cost-effective. Including herd effects improved value for money for MenB vaccines. Routine infant vaccination was the most effective short-term strategy, however, adolescent strategies offered the best value for money. Without herd immunity, routine infant vaccination had the lowest incremental cost-effectiveness ratio estimates.

CONCLUSION

Routine MenB vaccination does not offer substantial value for money, mainly due to high vaccine costs and low disease incidence.

Gene expression profiling reveals insights into infant immunological and febrile responses to group B meningococcal vaccine

Neisseria meningitidis is a major cause of meningitis and septicaemia. A MenB vaccine (4CMenB) was licensed by the European Medicines Agency in January 2013. Here we describe the blood transcriptome and proteome following infant immunisations with or without concomitant 4CMenB, to gain insight into the molecular mechanisms underlying post-vaccination reactogenicity and immunogenicity. Infants were randomised to receive control immunisations (PCV13 and DTaP-IPV-Hib) with or without 4CMenB at 2 and 4 months of age. Blood gene expression and plasma proteins were measured prior to, then 4 h, 24 h, 3 days or 7 days post-vaccination. 4CMenB vaccination was associated with increased expression of ENTPD7 and increased concentrations of 4 plasma proteins: CRP, G-CSF, IL-1RA and IL-6. Post-vaccination fever was associated with increased expression of SELL, involved in neutrophil recruitment. A murine model dissecting the vaccine components found the concomitant regimen to be associated with increased gene perturbation compared with 4CMenB vaccine alone with enhancement of pathways such as interleukin-3, -5 and GM-CSF signalling. Finally, we present transcriptomic profiles predictive of immunological and febrile responses following 4CMenB vaccine.

Predicted coverage by 4CMenB vaccine against invasive meningococcal disease cases in the Netherlands

Neisseria meningitidis serogroup B is a major cause of invasive meningococcal disease in Europe. In the absence of a conjugate serogroup B vaccine, a subcapsular 4CMenB vaccine was developed. Data on 4CMenB vaccine efficacy is still limited. Recently, genomic MATS (Meningococcal Antigen Typing System) was developed as a tool to predict strain coverage, using vaccine antigens sequence data. We characterized all invasive meningococcal isolates received by the Netherlands Reference Laboratory for Bacterial Meningitis (NRLBM) in two epidemiological years 2017-2019 using whole-genome sequencing and determined serogroup, clonal complex (cc) and estimated 4CMenB vaccine coverage by gMATS. Of 396 cases of invasive meningococcal disease, corresponding to an incidence of 1.22 cases/10⁵ inhabitants, 180 (45%) were serogroup W, 155 (39%) serogroup B, 46 (12%) serogroup Y, 10 (3%) serogroup C, 2 non-groupable (0.5%) and 3 (0.7%) unknown. The incidence was the highest among 0-4 years olds (4 cases/10⁵ inhabitants), and 57/72 (79%) of these cases were serogroup B. Serogroup W predominated among persons 45 years of age or older with 110/187 (59%) cases. Serogroup B isolates comprised 11 different clonal complexes, with 103/122 (84%) isolates belonging to 4 clonal complexes: cc32, cc41/44, cc269 and cc213. In contrast, serogroup W isolates were genetically similar with 95% belonging to cc11. Of 122 serogroup B isolates, 89 (73%; 95% CI: 64-80%) were estimated to be covered by 4CMenB and the degree of coverage varied largely by clonal complex and age. Among the 0-4 year olds, 25 of 43 (58%; 95% CI: 43-72%) MenB isolates were estimated to be covered. Since the coverage of the 4CMenB vaccine is dependent on circulating clonal complexes, our findings emphasize the need for surveillance of circulating meningococcal strains. In addition, estimation of age specific coverage is relevant to determine the right target age group for vaccination.

Immunological fingerprint of 4CMenB recombinant antigens via protein microarray reveals key immunosignatures correlating with bactericidal activity

Serogroup B meningococcus (MenB) is a leading cause of meningitis and sepsis across the world and vaccination is the most effective way to protect against this disease. 4CMenB is a multi-component vaccine against MenB, which is now licensed for use in subjects >2 months of age in several countries. In this study, we describe the development and use of an ad hoc protein microarray to study the immune response induced by the three major 4CMenB antigenic components (fHbp, NHBA and NadA) in individual sera from vaccinated infants, adolescents and adults. The resulting 4CMenB protein antigen fingerprinting allowed the identification of specific human antibody repertoire correlating with the bactericidal response elicited in each subject. This work represents an example of epitope mapping of the immune response induced by a multicomponent vaccine in different age groups with the identification of protective signatures. It shows the high flexibility of this microarray based methodology in terms of high-throughput information and minimal volume of biological samples needed.

4CMenB is an approved multi-component vaccine against Serogroup B meningococcus. Here the authors develop a protein microarray for three major 4CMenB antigenic components (fHbp, NHBA and NadA) and describe antibody repertoires in sera from vaccinated infants, adolescents and adults correlating with bactericidal response.

Understanding immunogenicity assessments for meningococcal serogroup B vaccines

Invasive meningococcal disease (IMD) is a potentially devastating infection associated with high mortality and long-term sequelae; however, vaccines are available to protect against the five common disease-causing serogroups (A, B, C, W, and Y). Because traditional field efficacy clinical trials were not feasible due to low IMD incidence that necessitates a very large number of participants, serum bactericidal antibody (SBA) assays using rabbit (rSBA) or human (hSBA) complement were established as in vitro surrogates of meningococcal vaccine efficacy and are now routinely used to support vaccine licensure. Specifically, rSBA assays have been used to evaluate responses to meningococcal capsular polysaccharide-protein conjugate vaccines against serogroups A, C, W, and Y; the accepted correlate of protection for rSBA assays is a titer ≥1:8. Importantly, because the bacterial capsular polysaccharide antigen is conserved across strains, only one test strain that expresses an invariant polysaccharide capsule for each serogroup is required to assess coverage. rSBA assays are unsuitable for subcapsular protein-based serogroup B (MenB) vaccines, and therefore, hSBA assays have been used for licensure; titers ≥1:4 are considered the correlate of protection against IMD for hSBA. In contrast to MenACWY vaccines, because bacterial surface proteins are antigenically variable, MenB vaccines must be tested with hSBA assays using multiple test strains that represent the antigenic diversity of disease-causing isolates. As this complexity regarding SBA assessment methods can make data interpretation difficult, herein we describe the use of hSBA assays to evaluate MenB vaccine efficacy and to support licensure. In addition, we highlight how the two recently approved MenB vaccines differ in their use of hSBA assays in clinical studies to demonstrate broad protection against MenB IMD.

Vaccination of Infants with Meningococcal Group B Vaccine (4CMenB) in England

BACKGROUND

In September 2015, the United Kingdom introduced the multicomponent meningococcal group B vaccine (4CMenB, Bexsero) into its publicly funded national immunization program at a reduced two-dose priming schedule for infants, with a 12-month booster.

METHODS

Using data from enhanced national surveillance of invasive meningococcal disease in England, we evaluated the effect of vaccination on the incidence of meningococcal group B disease during the first 3 years of the program. The effect of vaccination was assessed by comparing the observed incidence of disease with the expected incidence based on the incidence during the 4-year prevaccination period in equivalent cohorts and with the use of disease trends in cohorts of children younger than 5 years of age who were not eligible to receive the vaccine. Vaccine effectiveness was estimated with the use of the indirect screening method.

RESULTS

4CMenB uptake in England remained consistently high; data from the first 3 months of 2018 showed that 92.5% of children had completed the primary immunizations by their first birthday and 87.9% had received all three doses by 2 years. From September 2015 through August 2018, the incidence of meningococcal group B disease in England (average annual birth cohort, approximately 650,000 infants) was significantly lower in vaccine-eligible cohorts than the expected incidence (63 observed cases as compared with 253 expected cases; incidence rate ratio, 0.25; 95% confidence interval [CI], 0.19 to 0.36), with a 75% reduction in age groups that were fully eligible for vaccination. The adjusted vaccine effectiveness against meningococcal group B disease was 52.7% (95% CI, -33.5 to 83.2) with a two-dose priming schedule for infants and 59.1% (95% CI, -31.1 to 87.2) with a two-dose priming schedule plus a booster at 1 year). Over the 3-year period, there were 169 cases of meningococcal group B disease in the vaccine-eligible cohorts, and an estimated 277 cases (95% CI, 236 to 323) were prevented.

CONCLUSIONS

The 4CMenB program was associated with continued positive effect against meningococcal group B disease in children in England, and protection after three doses of the vaccine was sustained for at least 2 years. (Funded by Public Health England.).

Meningococcal Group B Vaccine For The Prevention Of Invasive Meningococcal Disease Caused By Neisseria meningitidis Serogroup B

Invasive meningococcal disease (IMD) is a major public health concern because of its high case fatality, long-term morbidity, and potential to course with outbreaks. IMD caused by Nesseira meningitidis serogroup B has been predominant in different regions of the world like Europe and only recently broadly protective vaccines against B serogroup have become available. Two protein-based vaccines, namely 4CMenB (Bexsero®) and rLP2086 (Trumenba®) are currently licensed for use in different countries against MenB disease. These vaccines came from a novel technology on vaccine design (or antigen selection) using highly specific antigen targets identified through whole-genome sequence analysis. Moreover, it has the potential to confer protection against non-B meningococcus and against other Neisserial species such as gonococcus. Real-world data on the vaccine-use are rapidly accumulating from the UK and other countries which used the vaccine for control of outbreak or as part of routine immunization program, reiterating its safety and efficacy. Additional data on real-life effectiveness, long-term immunity, and eventual herd effects, including estimates on vaccine impact for cost-effectiveness assessment are further needed. Given the predominance of MenB in Europe and other parts of the world, these new vaccines are crucial for the prevention and public health control of the disease, and should be considered.

The effect of a single 4CMenB vaccine booster in young people more than ten years after infant immunisation: protocol of an exploratory immunogenicity study

Background and rationale

The four-component capsular group B meningococcal vaccine (4CMenB) was introduced into the national immunisation schedule in the UK in September 2015 for infants in a 2 + 1 schedule at two, four and 12 months of age. A two-dose immunisation schedule for adolescents was also considered but was not found to be cost-effective in view of the relatively low rates of disease in this age group. Uncertainty about the longevity of protection induced by the vaccine and lack of certainty about an anamnestic response in primed individuals contributed to this decision.

Methods/Design

This study is an open-label, descriptive immunogenicity analysis. Up to 113 participants will be recruited, including up to 83 children who are now aged 11 years and took part in previous trials involving the administration of 4CMenB to infants, plus a group of 30 naïve age-matched controls. All previously immunised participants will receive one booster dose of 4CMenB. The 30 naïve participants will be randomised to receive two doses of 4CMenB either at 0 and 28 days or 0 and 365 days. Blood samples will be collected from all participants at 0, 28, 180 and 365 days. The primary endpoint will explore immunogenicity at day 0 and 180 in previously immunised and naïve participants. Secondary outcomes will include investigating the persistence of antibody protection in previously immunised participants at the beginning of the study, describing the characteristics of the memory B-cell responses in previously immunised participants, and measuring reactogenicity in all participants following 4CMenB doses.

Discussion

This study aims to describe whether or not a single booster dose of 4CMenB given to those who have received an infant course of 4CMenB induces a recall immune response, while concurrently describing immune responses in naïve children of the same age. If an anamnestic response is proven, a single dose adolescent booster could be envisaged as an addition to the current UK vaccination schedule.

Trial registration

EudraCT, 2017–004732-11. ISRCTN, ISRCTN16774163. Registered on 10 May 2018 (retrospectively registered).

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3494-1) contains supplementary material, which is available to authorized users.

Persistence of the immune response after 4CMenB vaccination, and the response to an additional booster dose in infants, children, adolescents, and young adults

The multicomponent meningococcal serogroup B vaccine, 4CMenB, has demonstrated effectiveness in preventing invasive MenB disease in infants and in controlling MenB outbreaks. The need for/timing of additional booster doses is not yet established. We reviewed eight studies that evaluated antibody persistence and booster following primary 4CMenB vaccination of infants, children, adolescents, and young adults. Putative seroprotective hSBA titers for ≥1 vaccine antigen were maintained by 76-100% of children 24-36 months after priming during infancy and in 84-100% after priming in the second year of life. hSBA levels were higher in vaccinees at 4 and 7.5 years following priming during adolescence than in vaccine-naïve individuals of a similar age. Antibodies persisted at higher levels to NHBA and NadA than to PorA or fHbp. Booster vaccination induced robust anamnestic responses, demonstrating effective priming by 4CMenB across age-groups. These data can inform decision-making to optimize vaccination strategies.

Potential benefits of using a multicomponent vaccine for prevention of serogroup B meningococcal disease

Meningococcal serogroup B (MenB) has become the main cause of invasive meningococcal disease in industrialized countries in recent years. The diversity of MenB strains and poor immunogenicity of the MenB capsular polysaccharide have made vaccine development challenging. Two MenB vaccines, including factor H binding protein (fHbp) as a major antigenic component, are now licensed for use. In addition to fHbp variant 1, the multicomponent vaccine 4CMenB contains neisserial heparin binding antigen, Neisseria adhesin A, and outer membrane vesicles containing porin A. The vast majority of circulating MenB strains contain genes encoding at least one 4CMenB component and many express genes for more than one vaccine antigen. Recent studies have suggested that serum bactericidal activity is enhanced against strains that express two or more vaccine antigens. Bacterial killing may also occur when antibodies to vaccine components are collectively present at levels that would individually be sub-lethal. The evaluation of immune responses to separate vaccine components does not take cooperative activity into account and may underestimate the overall protection. Available data on 4CMenB effectiveness indicate that this multicomponent vaccine affords broad coverage and protection against MenB disease. 4CMenB also has the potential to protect against disease caused by non-MenB meningococci and Neisseria gonorrhoeae.

Spontanuous Demand For Meningococcal B Vaccination: Effects On Appropriateness And Timing

When the meningococcus B vaccine was introduced into Italy in 2017, it was recommended for newborns based on national epidemiological data indicating that they were at greater risk. However, the vaccination service of the local health authority of L'Aquila had already been receiving spontaneous parental requests to provide vaccination for children in lower-risk age groups from the beginning of 2016. We therefore decided to use a self-administered questionnaire in order to investigate the parents’ socio-demographic data; their children's history of other recommended vaccinations (against measles, mumps and rubella, varicella, meningococcus C and, for females, human papilloma virus); the information sources concerning meningococcal vaccination; and the timing of its administration.

The questionnaire was completed by 565 parents, and the results showed that the requests mainly came from the parents of children aged 5–11 years. The children whose mothers had received a high school education and were >35 years old were more likely to have received the first dose after the age of one year and to have perceived pain at the inoculation site, and less likely to have experienced mild general reactions. The requests were mainly trigged by the recommendations of healthcare professionals, and the overloading of the vaccination service led to delays in the administration of the doses after the first. The delays (reported by 74.07% of the parents) were mainly due to organisational problems in the service itself, which led 61.52% of the doses being more appropriately administered by staff working as private physicians inside public health facilities, albeit at extra cost.

These findings indicate that organisational factors and excessive demand had a considerable impact on both the efficacy of the immunisation and its appropriateness.

Immunogenicity and safety of the multicomponent meningococcal B vaccine (4CMenB) in children and adolescents: a systematic review and meta-analysis

BACKGROUND

The multicomponent meningococcal serogroup B vaccine (4CMenB) has been licensed in more than 35 countries. However, uncertainties remain about the lowest number of doses required to induce satisfactory, persistent immune responses. We did a systematic review and meta-analysis to provide quantitative estimates for the immunogenicity, persistence of immunogenicity, and safety of 4CMenB vaccine in children and adolescents.

METHODS

For this systematic review and meta-analyses (proportion, head to head, and network), we searched MEDLINE, Scopus, Embase, and ClinicalTrials.gov from database inception to June 30, 2017, for randomised trials that compared the immunogenicity or safety of the 4CMenB vaccine with its originator meningococcal B recombinant vaccine or routine vaccines in children or adolescents. For proportion meta-analyses, we also included single arm trials and follow-up studies of randomised controlled trials. Trials that assessed immunogenicity against at least one of four Neisseria meningitidis serogroup B reference strains (44-76/SL, 5/99, NZ98/254, and M10713) and included participants younger than 18 years who had received two or more doses of the 4CMenB vaccine were eligible for inclusion. We requested individual patient-level data from study authors and extracted data from published reports and online trial registries. We did meta-analyses to assess 4CMenB safety and immunogenicity against the four reference strains 30 days after a primary immunisation course (three doses for children, two doses for adolescents), 30 days after the primary course plus one booster dose (children only), 6 months or more after primary course, and 6 months or more after the booster dose.

FINDINGS

736 non-duplicate records were screened, and ten randomised trials and eight follow-on extension trials on 4CMenB met the inclusion criteria. In intention-to-treat analyses, the overall proportion of children and adolescents who achieved seroconversion 30 days after the primary course of 4CMenB was 92% (95% CI 89-95 [I²=95%, p<0·0001]) for the 44/76-SL strain, 91% (87-95 [I²=95%, p<0·0001]) for the 5/99 strain, 84% (77-90 [I²=97%, p<0·0001]) for the NZ98-254 strain, and 87% (68-99 [I²=97%, p<0·0001]) for the M10713 strain. 6 months after the primary course, the immunogenicity remained adequate to high against all three tested strains (5/99, 44/76-SL, and NZ98/254) in adolescents (≥77%), and against two of four strains (5/99 and 44/76-SL) in children (≥67%): the proportion of patients who achieved seroconversion substantially declined for M10713 (<50%) and NZ98/254 (<35%). A booster dose re-enhanced the proportion of patients who achieved seroconversion (≥93% for all strains). However, immunogenicity remained high 6 months after the booster dose for strains 5/99 (95%) and M10713 (75%) only, whereas the proportion of patients who achieved seroconversion against strains 44/76-SL and NZ98/254 returned to similar proportions recorded 6 months after the primary course (62% for 44/76-SL, 35% for NZ98/254). The incidence of potentially vaccine-related, acute serious adverse events in individuals receiving 4CMenB was low (5·4 per 1000 individuals), but was significantly higher than routine vaccines (1·2 per 1000 individuals).

INTERPRETATION

4CMenB has an acceptable short-term safety profile. The primary course is sufficient to achieve a satisfactory immune response within 30 days of vaccination. A booster dose is required for children to prolong the protection against strain M10713, and the long-term immunogenicity against strain NZ98/254 remains suboptimal.

FUNDING

None.

Antibody persistence and booster responses 24-36 months after different 4CMenB vaccination schedules in infants and children: A randomised trial

OBJECTIVES

This phase IIIb, open-label, multicentre, extension study (NCT01894919) evaluated long-term antibody persistence and booster responses in participants who received a reduced 2 + 1 or licensed 3 + 1 meningococcal serogroup B vaccine (4CMenB)-schedule (infants), or 2-dose catch-up schedule (2-10-year-olds) in parent study NCT01339923.

MATERIALS AND METHODS

Children aged 35 months to 12 years (N = 851) were enrolled. Follow-on participants (N = 646) were randomised 2:1 to vaccination and non-vaccination subsets; vaccination subsets received an additional 4CMenB dose. Newly enrolled vaccine-naïve participants (N = 205) received 2 catch-up doses, 1 month apart (accelerated schedule). Antibody levels were determined using human serum bactericidal assay (hSBA) against MenB indicator strains for fHbp, NadA, PorA and NHBA. Safety was also evaluated.

RESULTS

Antibody levels declined across follow-on groups at 24-36 months versus 1 month post-vaccination. Antibody persistence and booster responses were similar between infants receiving the reduced or licensed 4CMenB-schedule. An additional dose in follow-on participants induced higher hSBA titres than a first dose in vaccine-naïve children. Two catch-up doses in vaccine-naïve participants induced robust antibody responses. No safety concerns were identified.

CONCLUSION

Antibody persistence, booster responses, and safety profiles were similar with either 2 + 1 or 3 + 1 vaccination schedules. The accelerated schedule in vaccine-naïve children induced robust antibody responses.

Persistence of immunity after vaccination with a capsular group B meningococcal vaccine in 3 different toddler schedules

BACKGROUND

One schedule for the capsular group B meningococcal vaccine 4CMenB is 2 doses that are administered 2 months apart for children aged 12-23 months, with a booster dose 12-24 months later. Our objective was to provide data on persistence of human serum bactericidal antibody (hSBA) titres in children up to 4 years of age after initial doses at 12-24 months, and immunogenicity of a booster dose at 48 months of age compared with vaccine-naive children.

METHODS

Children previously immunized, as part of a randomized controlled trial, with 2 doses of 4CMenB vaccine at 12-24 months of age received a booster at 4 years of age. Vaccine-naive age-matched toddlers received 2 doses of 4CMenB. Human serum bactericidal antibody titres against reference strains H44/76, 5/99, NZ98/254 and M10713 were evaluated before and after innoculation with 4CMenB vaccine in 4-year-old children.

RESULTS

Of 332 children in the study, 123 had previously received 4CMenB and 209 were vaccine-naive controls. Before the booster, the proportions of participants (previously vaccinated groups compared with controls) with hSBA titres of 1:5 or more were as follows: 9%-11% v. 1% (H44/76), 84%-100% v. 4% (5/99), 0%-18% v. 0% (NZ98/254) and 59%-60% v. 60% (M10713). After 1 dose of 4CMenB in previously immunized children, the proportions of participants achieving hSBA titres of 1:5 or more were 100% (H44/76 and 5/99), 70%-100% (NZ98/254) and 90%-100% (M10713).

INTERPRETATION

We found that waning of hSBA titres by 4 years of age occurred after 2 doses of 4CMenB vaccine administered at 12-24 months, and doses at 12-24 months have a priming effect on the immune system. A booster may be necessary to maintain hSBA titres of 1:5 or more among those children with increased disease risk. Trial registration: ClinicalTrials.gov, no. NCT01717638.

The next chapter for group B meningococcal vaccines

The majority of invasive meningococcal disease (IMD) in the developed world is caused by capsular group B Neisseria meningitidis, however success with vaccination against organisms bearing this capsule has previously been restricted to control of geographically limited clonal outbreaks. As we enter a new era, with the first routine program underway to control endemic group B meningococcal disease for infants in the UK, it is timely to review the key landmarks in group B vaccine development, and discuss the issues determining whether control of endemic group B disease will be achieved. Evidence of a reduction in carriage acquisition of invasive group B meningococcal strains, after vaccination among adolescents, is imperative if routine immunization is to drive population control of disease beyond those who are vaccinated (i.e. through herd immunity). The need for multiple doses to generate a sufficiently protective response and reactogenicity remain significant problems with the new generation of vaccines. Despite these limitations, early data from the UK indicate that new group B meningococcal vaccines have the potential to have a major impact on meningococcal disease, and to provide new insight into how we might do better in the future.

Reduced schedules of 4CMenB vaccine in infants and catch-up series in children: Immunogenicity and safety results from a randomised open-label phase 3b trial

BACKGROUND

This study evaluated the immunogenicity and safety of a licensed meningococcal serogroup B vaccine (4CMenB) administered alone according to reduced schedules in infants or catch-up series in children.

METHODS

In this open-label, multicentre, phase 3b study (NCT01339923), infants randomised 1:1:1 received 4CMenB: 2+1 doses at 3½-5-11months or 6-8-11months of age, 3+1 doses at ages 2½-3½-5-11months. Children aged 2-10years received 2 catch-up doses administered 2months apart. Immune responses were measured by hSBA assays against 4 strains specific for vaccine components fHbp, NadA, PorA and NHBA. Sufficiency of immune responses was defined in groups with 2+1 doses schedules as a lower limit ≥70% for the 97.5% confidence interval of the percentage of infants with hSBA titres ≥4, 1month post-dose 2 for fHbp, NadA, PorA. Adverse events were collected for 7days post-vaccination; serious adverse events (SAEs) throughout the study.

RESULTS

754 infants and 404 children were enrolled. Post-primary vaccination, 98-100% of infants across all groups developed hSBA titres ≥4 for fHbp, NadA, PorA, and 48-77% for NHBA. Sufficiency of immune responses in infants receiving 2+1 schedules was demonstrated for fHbp, NadA, PorA after 2 doses of 4CMenB, as pre-specified criteria were met. Following receipt of 2 catch-up doses, 95-99% of children developed hSBA titres ≥4 for 4CMenB components. Similar safety profiles were observed across groups. A total of 45 SAEs were reported, 3 of which were related to vaccination.

CONCLUSION

Reduced infant schedules and catch-up series in children were immunogenic and safe, having the potential to widen 4CMenB vaccine coverage.

FUNDING

GlaxoSmithKline Biologicals SA.

Emerging experience with meningococcal serogroup B protein vaccines

INTRODUCTION

The successful development of two broadly protective vaccines targeting Neisseria meningitidis serogroup B (MenB); 4CMenB and rLP2086, is the most significant recent advance in meningococcal disease prevention. Areas covered: Here we review the principles underlying the development of each vaccine and the novel methods used to estimate vaccine coverage. We update clinical and post-licensure experience with 4CMenB and rLP2086. Expert commentary: The immunogenicity and acceptable safety profile of 4CMenB and rLP2086 has been demonstrated in clinical trials. Continuing uncertainties exist around the appropriate age groups to be immunized, the degree and duration of efficacy, and the impact on nasopharyngeal carriage which has implications for strategies to interrupt transmission and maximize herd protection effects. Universal vaccination programs such as those undertaken in Quebec and the United Kingdom are providing important information on these issues. The potential for MenB vaccines to prevent infection by other serogroups appears promising, and the impact of MenB vaccines on other pathogenic neisserial species with similar surface proteins warrants further investigation.

Metabolic competition as a driver of bacterial population structure

Understanding the processes whereby diversity arises and is maintained in pathogen populations is pivotal for designing disease control interventions. A particular problem is the maintenance of strain structure in bacterial pathogen populations despite frequent genetic exchange. Although several theoretical frameworks have been put forward to explain this widespread phenomenon, few have focused on the role of genes encoding metabolic functions, despite an increasing recognition of their importance in pathogenesis and transmission. In this article, we review the literature for evidence of metabolic niches within the host and discuss theoretical frameworks which examine ecological interactions between metabolic genes. We contend that metabolic competition is an important phenomenon which contributes to the maintenance of population structure and diversity of many bacterial pathogens.

Background Paper for the update of meningococcal vaccination recommendations in Germany: use of the serogroup B vaccine in persons at increased risk for meningococcal disease

In December 2013 Bexsero® became available in Germany for vaccination against serogroup B meningococci (MenB). In August 2015 the German Standing Committee on Vaccination (STIKO) endorsed a recommendation for use of this vaccine in persons at increased risk of invasive meningococcal disease (IMD). This background paper summarizes the evidence underlying the recommendation. Bexsero® is based on surface protein antigens expressed by about 80% of circulating serogroup B meningococci in Germany. The paper reviews available data on immunogenicity and safety of Bexsero® in healthy children and adolescents; data in persons with underlying illness and on the effectiveness in preventing clinical outcomes are thus far unavailable.STIKO recommends MenB vaccination for the following persons based on an individual risk assessment: (1) Persons with congenital or acquired immune deficiency or suppression. Among these, persons with terminal complement defects and properdin deficiency, including those under eculizumab therapy, are at highest risk with reported invasive meningococcal disease (IMD) incidences up 10,000-fold higher than in the general population. Persons with asplenia were estimated to have a ~ 20-30-fold increased risk of IMD, while the risk in individuals with other immune defects such as HIV infection or hypogammaglobulinaemia was estimated at no more than 5-10-fold higher than the background risk. (2) Laboratory staff with a risk of exposure to N. meningitidis aerosols, for whom an up to 271-fold increased risk for IMD has been reported. (3) Unvaccinated household (-like) contacts of a MenB IMD index case, who have a roughly 100-200-fold increased IMD risk in the year after the contact despite chemoprophylaxis. Because the risk is highest in the first 3 months and full protective immunity requires more than one dose (particularly in infants and toddlers), MenB vaccine should be administered as soon as possible following identification of the serogroup of the index case.

Persistence of Bactericidal Antibodies After Infant Serogroup B Meningococcal Immunization and Booster Dose Response at 12, 18 or 24 Months of Age

BACKGROUND

A serogroup B meningococcal vaccine (4CMenB) is licensed for infant use in countries including Canada, Australia and those of the European Union. Data on serum bactericidal antibody (hSBA) waning and the ideal timing of a "toddler" booster dose are essential to optimize vaccine utilization.

METHODS

An open-labeled, multicenter phase-2b follow-on European study conducted from 2009 to 2012. Participants previously receiving 4CMenB with routine vaccines at 2, 4 and 6 or 2, 3 and 4 months (246Con and 234Con) or at 2, 4 and 6 months intercalated with routine vaccines (246Int) received a booster dose at 12, 18 or 24 months. 4CMenB-naïve "Control" participants aged 12, 18 or 24 months received 2 doses of 4CMenB 2 months apart.

RESULTS

One thousand five hundred eighty-eight participants were recruited. At 12 months, before any booster doses, the proportions with hSBA titers ≥1:5 for strain 44/76-SL (testing vaccine component fHBP) were 73% (120/165) for the "246Con" group, 85% (125/147) for "246Int," 57% (51/90) for "234Con" and 13% (26/199) for Controls. For strain 5/99 (NadA) proportions were ≥96% (all 4CMenB-recipients) and 1% (Controls). For strain NZ98/254 (PorA), these were 18-35% (4CMenB-recipients) and 1% (Controls). By 24 months, 4CMenB-recipient proportions were 13-22% (44/76-SL), 82-94% (5/99) and 7-13% (NZ98/254) and in controls ≤4%. After a 12-month booster-dose, ≥95% of previously immunized participants had titers ≥1:5 (all strains).

CONCLUSIONS

A 4CMenB booster-dose can overcome waning hSBA titers after early-infant immunization. Administration at 12 months could help to maintain immunity during an age of high risk, and the persistence of this response requires further study.

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.

A phase 2 randomized controlled trial of a multicomponent meningococcal serogroup B vaccine, 4CMenB, in infants (II)

The licensed meningococcal serogroup B vaccine, 4CMenB (Bexsero(®)), contains recombinant membrane proteins (rMenB) and outer membrane vesicles (OMV) of the New Zealand serogroup B strain. We investigated whether reducing the OMV and/or protein content influences 4CMenB immunogenicity and reactogenicity in healthy two month-old infants. Six formulations were studied: 4CMenB, rMenB with 0, ¼ or ½ the OMV dose in 4CMenB, a half-dose of 4CMenB or a prelicensure formulation of 4CMenB, as a 4-dose primary/booster series, concomitantly with routine vaccines (DTaP-HBV-IPV/Hib and 7-valent pneumococcal conjugate) at 2, 3, 4 and 12 months of age. Immunogenicity was assessed as serum bactericidal activity measured with human complement (hSBA) against indicator strains for Men B vaccine antigens before and after the 2,3,4-month series and 12-month dose. Parents recorded solicited reactions for 7 days after each vaccination, and any adverse events throughout the study period. All formulations elicited robust immune response against rMenB components at 5 months, there was some evidence of OMV and protein dose-dependence for Men B indicator strains tested. Titers waned up to the 12-month dose, which elicited further strong responses, which were still OMV and protein dose-dependent. Groups with no, or low-dose OMV displayed slightly lower reactogenicity profiles, but all formulations were generally well-tolerated, high fever was rare and transient, and only three transient SAEs were considered possibly vaccine-related. Decreasing or removing the OMV content reduced reactogenicity of 4CMenB to a certain extent, but had an unacceptable negative impact on the immunogenicity profile. Trial: Clinicaltrials.gov NCT00937521.

The multicomponent meningococcal serogroup B vaccine (4CMenB): origin, composition, health impact and unknown aspects

Neisseria meningitidis serogroup B is the main cause for meningococcal invasive disease in many parts of the world. Since 2013, a new multicomponent vaccine against meningococcal serogroup B (4CMenB) has been licensed in Europe, Australia, Canada, Chile, Uruguay, USA and Brazil with different immunization schedules. Clinical trials involving adults, adolescents, children and infants showed 4CMenB has a good immunogenicity and safety profile. Strain coverage estimates are similar to or better than other recently approved vaccines, ranging from 66% in Canada to 91% in Unites States. Some points still remain to be clarified such as the best immunization strategy, the effect of 4CMenB on carriage, the long-term persistence of protective bactericidal antibodies titers, long-term safety outcomes, the possible emergence of N. meningitidis escape mutants and the vaccine cost–effectiveness. In this review, we focus on the vaccine composition, clinical trials and suggested schedules, safety data, potential strain coverage and future challenges.

Meningococcal B Vaccination (4CMenB) in Infants and Toddlers

Neisseria meningitidis is a Gram-negative pathogen that actively invades its human host and leads to the development of life-threatening pathologies. One of the leading causes of death in the world, N. meningitidis can be responsible for nearly 1,000 new infections per 100,000 subjects during an epidemic period. The bacterial species are classified into 12 serogroups, five of which (A, B, C, W, and Y) cause the majority of meningitides. The three purified protein conjugate vaccines currently available target serogroups A, C, W, and Y. Serogroup B has long been a challenge but the discovery of the complete genome sequence of an MenB strain has allowed the development of a specific four-component vaccine (4CMenB). This review describes the pathogenetic role of N. meningitidis and the recent literature concerning the new meningococcal vaccine.

Meningococcal serogroup B vaccine (4CMenB): Booster dose in previously vaccinated infants and primary vaccination in toddlers and two-year-old children

OBJECTIVE

The multicomponent, recombinant serogroup B vaccine, 4CMenB, is approved in Europe, Canada and Australia from two months of age. We investigated persistence to booster doses at 12 months of age following infant vaccination, and immune response to catch-up vaccination of toddlers and children up to two years of age.

METHODS

We assessed persistence of immune responses after one year in participants vaccinated as infants, and responses to two doses at 12-15 or 24-26 months of age in vaccine-naïve children, as serum bactericidal activity with human complement (hSBA) against indicator strains for four vaccine antigens. Adverse events were recorded after each vaccination.

RESULTS

High antibody titers were induced against all four 4CMenB components following booster vaccination in infant-primed toddlers and after two doses in previously unvaccinated toddlers or two-year-olds. Antibodies waned over 12 months, particularly those against NZ OMV. Systemic reactogenicity in toddlers was lower than in infants, and lower again in vaccine-naïve two-year-olds. Local reactogenicity was common in all groups.

CONCLUSIONS

Four infant or two toddler 4CMenB vaccinations elicit immune responses believed to be protective for the first two years of life, which can be boosted. Reactogenicity is lower in toddlers than in infants.

Group B meningococcal vaccine science and policy

Capsular group B Neisseria meningitidis is one of the leading causes of death in developed countries. A new vaccine (4CMenB) has recently been developed which was found to have an acceptable safety profile in clinical studies and to be immunogenic. This review examines the evidence supporting the licensure of the 4CMenB vaccine and discusses recommendations for its use.

Persistence of specific bactericidal antibodies at 5 years of age after vaccination against serogroup B meningococcus in infancy and at 40 months

BACKGROUND

The multicomponent serogroup B meningococcal (4CMenB) vaccine induces antibodies against indicator strains of serogroup B meningococcus under various schedules. We investigated the persistence of antibodies in 5-year-old children 18-20 months after their last dose (at about 3.5 years of age).

METHODS

We assessed 5-year-old children who received the 4CMenB vaccine or a recombinant protein vaccine in a previous randomized trial. We also recruited 50 vaccine-naive 5-year-olds and administered 2 doses of 4CMenB to each child. We measured serum bactericidal antibody titres against 4 indicator strains of serogroup B meningococcus matched to each individual vaccine component and against 4 mismatched strains.

RESULTS

Of those who received the 4CMenB vaccine at 2, 4, 6, 12 and 40 months (n = 16), the percentage with protective antibody titres (≥ 1:4) at 60 months ranged from 44% to 88% against matched strains and from 13% to 81% against mismatched strains. Loss of protective titres was also observed for those who received the 4CMenB vaccine at 12, 40 and 42 months (n = 5) (80%-100% against matched strains, 60%-100% against mismatched strains) or at 40 and 42 months (n = 29) (31%-100% against matched strains, 41%-81% against mismatched strains). Administering the 4CMenB vaccine to 5-year-old children yielded protective titres against matched strains in 92%-100% and against mismatched strains in 59%-100%. The majority of these children reported injection-site pain (40/50 [80%] after dose 1, 39/46 [85%] after dose 2) and erythema (47/50 [94%] and 40/46 [87%], respectively); rates of fever were low (5/50 [10%] and 2/46 [4%], respectively).

INTERPRETATION

Waning of immunity by 5 years of age occurred after receipt of the 4CMenB vaccine in infancy, even with an additional booster at 40 months. The 4CMenB vaccine is immunogenic and was fairly well tolerated by 5-year-old children, although injection-site pain was noteworthy.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT01027351.

Neisseria meningitidis factor H-binding protein fHbp: a key virulence factor and vaccine antigen

Neisseria meningitidis is a leading cause of meningitis and sepsis worldwide. The first broad-spectrum multicomponent vaccine against serogroup B meningococcus (MenB), 4CMenB (Bexsero(®)), was approved by the EMA in 2013, for prevention of MenB disease in all age groups, and by the US FDA in January 2015 for use in adolescents. A second protein-based MenB vaccine has also been approved in the USA for adolescents (rLP2086, Trumenba(®)). Both vaccines contain the lipoprotein factor H-binding protein (fHbp). Preclinical studies demonstrated that fHbp elicits a robust bactericidal antibody response that correlates with the amount of fHbp expressed on the bacterial surface. fHbp is able to selectively bind human factor H, the key regulator of the alternative complement pathway, and this has important implications both for meningococcal pathogenesis and for vaccine design. Here, we review the functional and structural properties of fHbp, the strategies that led to the design of the two fHbp-based vaccines and the data generated during clinical studies.

A multi-component meningococcal serogroup B vaccine (4CMenB): the clinical development program

Recently approved in Europe and Australia, the multi-component meningococcal B vaccine, 4CMenB (Bexsero^®, Novartis Vaccines and Diagnostics), contains three surface-exposed recombinant proteins (fHbp, NadA, and NHBA) and New Zealand strain outer membrane vesicles (NZ OMV) with PorA 1.4 antigenicity. This comprehensive review of the 4CMenB clinical development program covers pivotal phase I/IIb/III studies in over 7,000 adults, adolescents, and infants. The immunological correlate for clinical protection used was human complement-mediated serum bactericidal activity titers ≥4 or 5 against indicator strains for individual antigens. Based on achievement of protective titers, a four-dose schedule (three primary doses and one booster dose) for infants and a two-dose schedule for adolescents provided the best results. Observed increases in injection site pain/tenderness and fever in infants, and injection site pain, malaise, and headache in adolescents compared with routine vaccines, were mostly mild to moderate; frequencies of rare events (Kawasaki disease, juvenile arthritis) were not significantly different from non-vaccinated individuals. 4CMenB is conservatively estimated to provide 66–91 % coverage against meningococcal serogroup B strains worldwide.

The capsular group B meningococcal vaccine, 4CMenB : clinical experience and potential efficacy

INTRODUCTION

Capsular group B meningococcal disease is a leading cause of childhood meningitis and septicaemia. Up to 10% of sufferers die, and sequelae remain in > 30% of survivors. A vaccine, four component meningococcal group B ( 4CMenB ), designed with the aim to induce broad coverage against this highly variable bacterium, has been licensed in countries including in the European Union, Canada and Australia.

AREAS COVERED

Immunogenicity and safety data, published in peer-reviewed literature between 2004 and 2014, are presented in the context of the recent recommendation for the use of the vaccine in infants in the UK.

EXPERT OPINION

4CMenB induces significant reactogenicity when administered with routine infant vaccines, in particular with respect to fever rates. Fevers can be somewhat reduced using paracetamol. The efficacy of the vaccine is unknown but has been extrapolated from effectiveness data obtained from use of one of its components in New Zealand, immunogenicity data from clinical trials and estimation of coverage from in vitro studies. These data suggest that the vaccine will prevent a proportion of invasive meningococcal disease cases in infants and young children. Implementation and well-planned post-marketing surveillance will address uncertainties over field effectiveness.

Child and adolescent immunizations: selected review of recent US recommendations and literature

PURPOSE OF REVIEW

To provide a clinically relevant summary of the latest research and recommendations regarding childhood and adolescent immunizations.

RECENT FINDINGS

Childhood vaccination has dramatically reduced pediatric morbidity and mortality in the United States. Recent research on childhood and adolescent immunizations has focused on expanding the use of current vaccines for additional subpopulations as well as the development of new vaccines. In particular, data confirming the safety and immunogenicity of vaccines in various groups of children have shaped national guidelines. Furthermore, studies on vaccine uptake, cost-effectiveness, and impact of vaccination have reinforced the importance of adhering to these guidelines. More work needs to be done by providers and parents to increase vaccination coverage rates to better protect children and adolescents from these serious diseases. In this article, selected recent publications and recommendations on the following vaccines are reviewed: influenza, meningococcal conjugate, childhood and adolescent/adult formulations of diphtheria and tetanus toxoids and acellular pertussis, pneumococcal conjugate, and human papillomavirus.

SUMMARY

Research on childhood and adolescent vaccinations continues to shape future guidelines. Through this work, we can learn how to optimize the protection of all children and adolescents against vaccine-preventable diseases.