Meningococcal serogroup B vaccination series initiation in the United States: A real-world claims data analysis

In the United States (US), meningococcal serogroup B (MenB) vaccination has been recommended for 16-23-year-olds (preferably 16-18 years) based on shared clinical decision-making since 2015. MenB vaccine coverage (≥1 dose) by age 17 years has been reported, but initiation at older ages and by insurance type is unknown. In this retrospective cohort study, MarketScan claims data were analyzed to assess MenB vaccine series initiation (i.e. receipt of a first dose) during 2017-2020 among US commercially insured and Medicaid-covered individuals aged 16-18 and 19-23 years. Kaplan-Meier curves were generated to estimate series initiation at various times from index (latest of 1/1/2017 or 16^th/19^th birthday, depending on the cohort). Multivariable analyses were conducted to identify factors associated with series initiation. Among 1,450,354 Commercial and 1,140,977 Medicaid 16-18-year-olds, MenB vaccine series initiation rates within 3 years of each person's first eligibility were estimated to be 33% and 20%, respectively; among 1,857,628 Commercial and 747,483 Medicaid 19-23-year-olds, 3% and 1%, respectively. Factors identified to be significantly associated with increased likelihood of initiating a MenB vaccine series included co-administration of meningococcal serogroups ACWY (MenACWY) vaccine, younger age, female sex, nonwhite race (Medicaid only), New England or Middle Atlantic location (Commercial only), urban residence, and previous influenza vaccination. MenB vaccine series initiation among the studied US adolescents and young adults was low. There is a need for continued efforts to better understand barriers to the uptake of vaccines that are recommended based on shared clinical decision-making.

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.

Use of expanded Neisseria meningitidis serogroup B panels with the serum bactericidal antibody assay for the evaluation of meningococcal B vaccine effectiveness

INTRODUCTION

Neisseria meningitidis serogroup B (NmB) antigens are inherently diverse with variable expression among strains. Prediction of meningococcal B (MenB) vaccine effectiveness therefore requires an assay suitable for use against large panels of epidemiologically representative disease-causing NmB strains. Traditional serum bactericidal antibody assay using exogenous human complement (hSBA) is limited to the quantification of MenB vaccine immunogenicity on a small number of indicator strains.

AREAS COVERED

Additional and complementary methods for assessing strain coverage developed previously include the Meningococcal Antigen Typing System (MATS), Meningococcal Antigen Surface Expression (MEASURE) assay, and genotyping approaches, but these do not estimate vaccine effectiveness. We provide a narrative review of these methods, highlighting a more recent approach involving the hSBA assay in conjunction with expanded NmB strain panels: hSBA assay using endogenous complement in each vaccinated person's serum (enc-hSBA) against a 110-strain NmB panel and the traditional hSBA assay against 14 (4 + 10) NmB strains.

EXPERT OPINION

The enc-hSBA is a highly standardized, robust method that can be used in clinical trials to measure the immunological effectiveness of MenB vaccines under conditions that mimic real-world settings as closely as possible, through the use of endogenous complement and a diverse, epidemiologically representative panel of NmB strains.

Genetic Features of a Representative Panel of 110 Meningococcal B Isolates to Assess the Efficacy of Meningococcal B Vaccines

Predictions of vaccine efficacy against Neisseria meningitidis serogroup B (NmB) disease are hindered by antigenic variability, limiting the representativeness of individual NmB isolates. A qualitative human serum bactericidal assay using endogenous complements of individual subjects (enc-hSBA) enables large panels of NmB isolates to be tested. A 110-isolate panel was randomly selected from 442 invasive NmB isolates from United States cases reported to the Centers for Disease Control (CDC) from 2000 to 2008. Typing analyses confirmed the 110-isolate panel is representative of the 442 isolates. The genetic features of the 110-isolate panel were compared against over 4,200 invasive NmB isolates collected from 2000 to 2018 in the United States, Australia, Canada, and nine European countries. Clonal complexes in the 110-isolate panel are also present in each geographical region; cumulative percentages show that these account for around 81% of the clonal complexes found in NmB isolates in other panels. For the antigens (fHbp, NHBA, PorA1.4, NadA) included in the currently licensed meningococcal serogroup B (MenB) vaccines, specifically considering the presence of at least one antigen with a matched genotype, the 110-isolate panel represents approximately 89% of the NmB isolates circulating worldwide, ranging from 87% for the European isolates to 95% and 97% for NmB isolates in the United States and Australia, respectively. The 110-isolate panel includes the most prevalent clonal complexes and genetic variants of MenB vaccine antigens found in a multinational collection of invasive NmB isolates. This panel is useful for assessing the efficacy of MenB vaccines in clinical trials worldwide.

IMPORTANCENeisseria meningitidis serogroup B (NmB) is a major cause of invasive meningococcal disease (IMD). Predicting the effectiveness of vaccines against NmB is difficult because NmB is an uncommon disease and because antigens targeted by meningococcal serogroup B (MenB) vaccines have highly variable genetic features and expression levels. Therefore, a large number of NmB isolates from different regions would need to be tested to comprehensively assess vaccine effectiveness. We examined a panel of 110 isolates obtained from NmB IMD cases in the United States and compared the genetic features of this panel with those of panels from different countries around the world. We found the 110-isolate panel included the most common clonal complexes and genetic variants of MenB vaccine antigens that exist in the global collections of invasive NmB isolates. This confirms the value of the NmB 110-isolate panel in understanding the effectiveness of MenB vaccines in clinical trials worldwide.

A phase 3 study to assess the immunogenicity, safety, and tolerability of MenB-FHbp administered as a 2-dose schedule in adolescents and young adults

BACKGROUND

The MenB-FHbp vaccine is licensed to prevent meningococcal serogroup B disease on either a 2-dose (0, 6 months) or 3-dose (0, 1-2, 6 months) series. This phase 3 study further assessed the immunogenicity and safety of the 2-dose MenB-FHbp schedule.

METHODS

Subjects 10-25 years of age received MenB-FHbp (months 0, 6) and the quadrivalent meningococcal conjugate vaccine MenACWY-CRM (month 0). Primary immunogenicity endpoints included percentages of subjects achieving ≥ 4-fold increases from baseline in serum bactericidal antibody using human complement (hSBA) titers for 4 diverse, vaccine-heterologous primary serogroup B test strains and titers ≥ lower limit of quantitation (LLOQ; 1:8 or 1:16) for all 4 primary strains combined (composite response) after dose 2; a titer ≥ 1:4 is the accepted correlate of protection. Percentages of participants with hSBA titers ≥ LLOQ for 10 additional vaccine-heterologous strains were also assessed; positive predictive values of primary strain responses for secondary strain responses were determined. Safety was assessed.

RESULTS

Overall, 1057 subjects received dose 1 and 946 received dose 2 of MenB-FHbp. Percentages of participants achieving ≥ 4-fold increases in hSBA titers against each primary strain after dose 2 ranged from 67.4% to 95.0% and the composite response was 74.3%. Primary strain responses were highly predictive of secondary strain responses. Most reactogenicity events were mild-to-moderate in severity and did not lead to withdrawal from the study. Adverse events (AEs) considered by the investigator to be related to vaccination occurred in 4.2% (44/1057) of subjects, and there were no serious AEs or newly diagnosed chronic medical conditions considered related to vaccination.

CONCLUSIONS

MenB-FHbp administered at 0, 6 months was well tolerated and induced protective bactericidal antibody responses against diverse serogroup B strains. Findings provide further support for the continued use of MenB-FHbp on a 2-dose schedule in this population.

Methods to evaluate serogroup B meningococcal vaccines: From predictions to real-world evidence

Serogroup B meningococci (MenB) remain a prominent cause of invasive meningococcal disease (IMD). The protein-based multicomponent 4CMenB and the bivalent MenB-FHbp are the only currently available vaccines against MenB-caused IMD. Efficacy studies are not possible, due to the low incidence of IMD. Therefore, the vaccines' immunogenicity has been evaluated against several target strains chosen to quantify complement-mediated killing induced by each vaccine component in the serum bactericidal antibody assay. However, due to the wide genetic diversity and different expression levels of vaccine antigens across MenB strains, vaccine performance may differ from one strain to another. Here, we review the methods used to predict MenB strain coverage for 4CMenB and MenB-FHbp. Phenotypic assays such as the meningococcal antigen typing system (MATS, 4CMenB-specific) and the flow cytometric meningococcal antigen surface expression assay (MEASURE; MenB-FHbp-specific) were developed. Genomic approaches are also available, such as genetic MATS (gMATS) and the Bexsero antigen sequence type (BAST) scheme, both 4CMenB-specific. All methods allow tentative predictions of coverage across MenB strains, including that afforded by each vaccine antigen, and are rapid and reproducible. Real-world data on vaccine effectiveness are needed to confirm predictions obtained by these methods.

A review of the immunogenicity, safety and current recommendations for the meningococcal serogroup B vaccine, MenB-FHbp

WHAT IS KNOWN AND OBJECTIVE

This review describes invasive meningococcal disease (IMD) epidemiology in the United States, provides a brief overview of available meningococcal vaccines and discusses meningococcal serogroup B (MenB) vaccine development. Particular focus is given to the recombinant protein MenB vaccine, MenB-FHbp (Trumenba^® , bivalent rLP2086) in light of recent publication of phase 3 data; the other MenB vaccine (Bexsero^® , MenB-4C) has been recently reviewed. Current recommendations of the US Advisory Committee on Immunization Practices (ACIP) for MenB vaccination and potential barriers to immunization are also discussed.

METHODS

Using the published literature, this article reviews the development and use of MenB-FHbp to date, with a focus on the United States.

RESULTS AND DISCUSSION

Despite the availability of medical treatment, IMD is associated with significant mortality and frequently occurring serious permanent sequelae in surviving individuals. Worldwide, most IMD is caused by six serogroups (A, B, C, W, X and Y). MenB is the most common disease-causing meningococcal serogroup in the United States and has caused several recent university-based IMD outbreaks. MenB vaccines, including MenB-FHbp, are available in the United States. ACIP recommends that all individuals ≥10 years of age at increased risk for meningococcal disease receive MenB vaccination; healthy individuals 16-23 years of age are recommended MenB vaccines based on individual clinical decision-making. MenB-FHbp is used on a 2-dose schedule (0, 6 months) when vaccinating healthy individuals and on a tailored 3-dose schedule (0, 1-2, 6 months) in cases of increased risk.

WHAT IS NEW AND CONCLUSION

Because vaccination provides the most effective protection against IMD, pharmacists are in an excellent position to offer evidence-based vaccine information, as well as to encourage and provide meningococcal immunizations to adolescents and young adults.

A physician's guide to the 2-dose schedule of MenB-FHbp vaccine

Meningococcal serogroup B (MenB) is the predominant cause of invasive meningococcal disease in the United States, with older adolescents and young adults attending college at increased risk. Notably, MenB caused all meningococcal disease outbreaks at US colleges between 2011 and 2018. MenB disease is vaccine-preventable. The MenB-FHbp vaccine can be administered on a 2-dose (0 and 6 months) schedule to healthy adolescents and young adults or as a tailored 3-dose (0, 1-2, and 6 months) schedule for individuals at increased risk. This review focuses on the 2-dose schedule (0 and 6 months) of MenB-FHbp. Clinical evidence demonstrating strong and broadly protective immunogenicity in adolescents after primary vaccination, immune persistence up to 48 months post-primary vaccination (18-61% of subjects across schedules), and immune memory evidenced by robust response to a single booster dose are described. Implementation approaches to ensure adolescents and young adults are fully vaccinated against meningococcal disease are discussed.

Concomitant administration of meningococcal vaccines with other vaccines in adolescents and adults: a review of available evidence

Invasive meningococcal disease (IMD), a rapidly progressing and potentially fatal illness, disproportionately affects adolescents and young adults. While IMD is best prevented by vaccination, vaccine uptake in these groups is low. An evidence-based understanding of the safety and effectiveness of concomitant vaccination of meningococcal vaccines, including the newer MenB protein vaccines and the more established MenACWY conjugate vaccines, with other vaccines recommended for adolescents and young adults may help maximize vaccination opportunities. We identified 21 studies assessing concomitant administration of meningococcal vaccines with other vaccines in adolescents and adults. Although studies varied in methodology, concomitant administration generally did not affect immunogenicity of the meningococcal or coadministered vaccines. In some cases, reactogenicity increased following concomitant administration, but no definitive safety concerns were raised. In general, data suggest that meningococcal vaccines can be safely and effectively coadministered with other vaccines.

Clinical data supporting a 2-dose schedule of MenB-FHbp, a bivalent meningococcal serogroup B vaccine, in adolescents and young adults

Invasive meningococcal disease (IMD) caused by Neisseria meningitidis is a potentially devastating condition that can result in death and is associated with serious long-term sequelae in survivors. Vaccination is the preferred preventative strategy. Quadrivalent polysaccharide-based vaccines that protect against infection caused by meningococcal serogroups A, C, W, and Y are not effective against meningococcal serogroup B (MenB), which was responsible for approximately 60% and 35% of confirmed IMD cases in the European Union and the United States in 2016, respectively. A recombinant protein MenB vaccine (MenB-FHbp [bivalent rLP2086; Trumenba®]) has been approved for protection against MenB infection in persons 10-25 years of age in the United States and Canada and for individuals ≥10 years of age in the European Union and Australia. In these regions, MenB-FHbp is approved as a 2- or 3-dose primary vaccination schedule. This report will review the current evidence supporting administration of MenB-FHbp as a 2-dose primary vaccination schedule. Different contexts in which a 2- or 3-dose primary vaccination schedule might be preferred (eg, routine prospective vaccination vs outbreak control) are reviewed.

Meningococcal Carriage Following a Vaccination Campaign With MenB-4C and MenB-FHbp in Response to a University Serogroup B Meningococcal Disease Outbreak-Oregon, 2015-2016

Background

Limited data exist on the impact of the serogroup B meningococcal (MenB) vaccines MenB-FHbp and MenB-4C on meningococcal carriage and herd protection. We therefore assessed meningococcal carriage following a MenB vaccination campaign in response to a university serogroup B meningococcal disease outbreak in 2015.

Methods

A convenience sample of students recommended for vaccination provided oropharyngeal swab specimens and completed questionnaires during 4 carriage surveys over 11 months. Isolates were tested by real-time polymerase chain reaction analysis, slide agglutination, and whole-genome sequencing. Vaccination history was verified via university records and the state immunization registry.

Results

A total of 4225 oropharyngeal swab specimens from 3802 unique participants were analyzed. Total meningococcal and genotypically serogroup B carriage prevalence among sampled students were stable, at 11%-17% and 1.2%-2.4% during each round, respectively; no participants carried the outbreak strain. Neither 1-3 doses of MenB-FHbp nor 1-2 doses of MenB-4C was associated with decreased total or serogroup B carriage prevalence.

Conclusions

While few participants completed the full MenB vaccination series, limiting analytic power, these data suggest that MenB-FHbp and MenB-4C do not have a large, rapid impact on meningococcal carriage and are unlikely to provide herd protection in the context of an outbreak response.