Meningococcal Vaccine Research Articles

Immune persistence and booster response of a quadrivalent meningococcal conjugate vaccine (MenACYW-TT) 5 years after primary vaccination of adults at ≥56 years of age

Immune persistence and booster response of a quadrivalent meningococcal conjugate vaccine (MenACYW-TT) 5 years after primary vaccination of adults at ≥56 years of age

Immunity Dynamics of Neisseria meningitidis Serogroups ACYW from Birth and Following Vaccination

Background: Serosurveillance of epidemic cerebrospinal meningitis (ECM) in healthy individuals is crucial for assessing disease risk and evaluating the effectiveness of vaccinations. However, this practical work is rare in China. Methods: We conducted cross-section serosurveillance in Guangzhou, Zhanjiang, and Heyuan in Guangdong Province, measuring Anti-Nm IgG with serogroups A, C, Y, and W, and analyzed the trends using a generalized additive model (GAM). Results: During 2019–2022, 7752 participants were included. The overall antibody positivity rate for serogroups A, C, Y, and W were 60.75%, 15.51%, 32.83%, and 14.56%, respectively. High Anti-Nm IgG was in children aged 0–5 and 5–10 years old. Geometric mean concentrations (GMCs) of Anti-Nm IgG were higher and correlated positively with vaccine doses compared with unvaccinated individuals. The GMC showed a consistent decrease trend in the vaccinated and a U-shaped curve in populations. The declined rates of GMC were 1.59 (95% CI: 1.03, 2.14) µg/mL, 1.65 (95% CI: 1.28, 2.03), 0.62 (95% CI: 0.22, 1.03), and 0.31 (95% CI: 0.08, 0.53) µg/mL per year for serogroups A, C, Y, and W, respectively. Conclusions: There were differences in antibody positivity rate and GMC for the four serogroups of ECM in the healthy individuals of Guangdong Province, with serogroup A showing the highest, and the demographic differences highlighted the high seroprevalence of Neisseria meningitidis in younger people. The variable prevalence rates among serogroups A, C, Y, and W and the observed decline in antibody titers underscore the need for adjustments in the immunization program targeting the meningococcal vaccine.

Exploring the sequence diversity and surface expression of Factor H-Binding Protein among invasive serogroup B meningococcal strains from selected European countries

ABSTRACT Factor H-Binding Protein (fHbp) is a key component of meningococcal vaccines such as MenB-fHbp, licensed in the EU, UK, and other countries. Sufficient expression of fHbp on the bacterial surface is necessary for vaccine-induced antibodies to bind and exert bactericidal activity. The flow cytometric MEASURE assay quantifies fHbp expression in vitro, and previous studies have shown that strains with a Mean Fluorescence Intensity (MFI) >1000 are likely to be killed by MenB-fHbp-induced antibodies. This study assessed fHbp peptide distribution and expression among 451 invasive group B strains collected in 2016 across England, Wales, and Northern Ireland (EW&NI), Germany, Italy, and Spain. We found that 92% of the strains expressed fHbp above the MFI 1000 threshold. The strain distribution across EW&NI, Germany, and Italy was similar, with coverage ranging from 92.1% to 94.6%, dominated by a small number of clonal complexes and fHbp peptides. Although, the Spanish subset had a higher proportion of lower-expressing strains, particularly clonal complex 213, resulting in a lower predicted coverage for Spain (84%). These results, along with other published MEASURE data, can provide a basis for genotypic MenB-fHbp coverage predictions, however, inclusion of the upstream intergenic sequence of the fHbp gene in the prediction improved its accuracy by distinguishing between low- and high-expressing strains. Future MEASURE analyses of strains with less common fHbp variants would serve to further refine vaccine coverage predictions.

Eculizumab Use in Neuromyelitis Optica Spectrum Disorders: Routine Clinical Care Data From a European Cohort.

Attack prevention is crucial in managing neuromyelitis optica spectrum disorders (NMOSDs). Eculizumab (ECU), an inhibitor of the terminal complement cascade, was highly effective in preventing attacks in a phase III trial of aquaporin-4 (AQP4)-IgG seropositive(+) NMOSDs. In this article, we evaluated effectiveness and safety of ECU in routine clinical care. We retrospectively evaluated patients with AQP4-IgG+ NMOSD treated with ECU between December 2014 and April 2022 at 20 German and 1 Austrian university center(s) of the Neuromyelitis Optica Study Group (NEMOS) by chart review. Primary outcomes were effectiveness (assessed using annualized attack rate [AAR], MRI activity, and disability changes [Expanded Disability Status Scale {EDSS}]) and safety (including adverse events, mortality, and attacks after meningococcal vaccinations), analyzed by descriptive statistics. Fifty-two patients (87% female, age 55.0 ± 16.3 years) received ECU for 16.2 (interquartile range [IQR] 9.6 - 21.7) months. Forty-five patients (87%) received meningococcal vaccination before starting ECU, 9 with concomitant oral prednisone and 36 without. Seven of the latter (19%) experienced attacks shortly after vaccination (median: 9 days, IQR 6-10 days). No postvaccinal attack occurred in the 9 patients vaccinated while on oral prednisone before starting ECU and in 25 (re-)vaccinated while on ECU. During ECU therapy, 88% of patients were attack-free. The median AAR decreased from 1.0 (range 0-4) in the 2 years preceding ECU to 0 (range 0-0.8; p < 0.001). The EDSS score from start to the last follow-up was stable (median 6.0), and the proportion of patients with new T2-enhancing or gadolinium-enhancing MRI lesions in the brain and spinal cord decreased. Seven patients (13%) experienced serious infections. Five patients (10%; median age 53.7 years) died on ECU treatment (1 from myocardial infarction, 1 from ileus with secondary sepsis, and 3 from systemic infection, including 1 meningococcal sepsis), 4 were older than 60 years and severely disabled at ECU treatment start (EDSS score ≥ 7). The overall discontinuation rate was 19%. Eculizumab proved to be effective in preventing NMOSD attacks. An increased risk of attacks after meningococcal vaccination before ECU start and potentially fatal systemic infections during ECU-particularly in patients with comorbidities-must be considered. Further research is necessary to explore optimal timing for meningococcal vaccinations. This study provides Class IV evidence that eculizumab reduces annualized attack rates and new MRI lesions in AQP4-IgG+ patients with NMOSD.

Eculizumab in AQP4-IgG NMOSD: Efficacy in the Real World and Potential Warning of Meningococcal Vaccines.

Eculizumab in AQP4-IgG NMOSD: Efficacy in the Real World and Potential Warning of Meningococcal Vaccines.

Safety and immunogenicity of a pentavalent meningococcal conjugate vaccine versus a quadrivalent meningococcal conjugate vaccine in adults in India: an observer-blind, randomised, active-controlled, phase 2/3 study

Meningococcal disease remains an important public health problem globally. We assessed the non-inferiority and the lot-to-lot consistency of a pentavalent meningococcal ACYWX conjugate vaccine (NmCV-5; Serum Institute of India, Pune, India) versus a quadrivalent meningococcal ACWY conjugate vaccine (MenACWY-D) in healthy adults. In this observer-blind, randomised, active-controlled, phase 2/3 study, healthy adults aged 18-85 years were recruited from nine hospitals across seven cities in India. Participants were grouped by age (age 18-29, 30-60, and 61-85 years), and within each age group they were randomly assigned (3:1) to receive either NmCV-5 or MenACWY-D (Sanofi Pasteur). In the age 18-29 years group, participants were additionally randomly assigned (1:1:1:1) to either lot A, lot B, or lot C of NmCV-5 or MenACWY-D. Block randomisation was used (block sizes of 4, 8, and 12). Study participants and study personnel were masked to treatment assignment. Participants received either a 0·5 mL dose of NmCV-5, containing 5 μg each of conjugated A, C, W, Y, and X polysaccharides, or 0·5 mL MenACWY-D, containing 4 μg of each of conjugated A, C, W, and Y polysaccharides. Vaccinations were administered intramuscularly in the deltoid muscle. The primary outcomes were seroresponse (non-inferiority margin of -10%) and geometric mean titres (GMTs; non-inferiority margin of 0·5) in all participants, and lot-to-lot consistency of NmCV-5 (in participants aged 18-29 years; consistency was shown if the geometric mean ratio [GMR] 95% CIs were within the limit interval of 0·5 to 2). For non-inferiority, serogroup X immune response in the NmCV-5 group was compared with the lowest immune response among serogroups A, C, W, and Y in the MenACWY-D group. Immunogenicity was assessed with a serum bactericidal activity assay that used baby rabbit serum as the complement (rSBA) on days 1 and 29 in the modified per-protocol population (including all participants who were randomly assigned, received vaccine, had a post-vaccination rSBA measurement up to 121 days after vaccination, and no major protocol violations). Solicited events were collected for 7 days and serious adverse events were collected for 180 days, and assessed in the safety population (all participants who received vaccination). This study is registered with ClinicalTrials.gov, NCT04358731, and CTRI, CTRI/2019/12/022436, and is now complete. Between Dec 27, 2019, and Sept 19, 2020, 1712 individuals were screened, of whom 1640 were randomly assigned and received NmCV-5 (n=1233) or MenACWY-D (n=407; mean age 26·4 years [SD 12·2], 551 [33·6%] of 1640 were female, and 1089 [66·4%] were male). 1441 participants were aged 18-29 years (362 received lot A, 360 received lot B, and 361 received lot C of NmCV-5 and 357 received MenACWY-D, with one participant mis-randomised by age group and excluded from lot-to-lot consistency analysis). Non-inferiority of NmCV-5 against MenACWY-D was met in terms of seroresponse rates and GMT ratios for all five serogroups. The seroresponse rates were 84·3% (97·5% CI 81·7 to 86·7; serogroup A) or higher in the NmCV-5 group and 54·5% (48·5 to 60·3; serogroup A) or higher in the MenACWY-D group, with the difference in the seroresponse rate between vaccine groups ranging from 0·2 (97·5% CI -2·2 to 2·6) for serogroup W to 29·8 (24·4 to 35·2) for serogroup A. GMTs on day 29 were 7016·9 (97·5% CI 6475·7 to 7603·4; serogroup Y) or higher in the NmCV-5 group and 3646·8 (3188·2 to 4171·5; serogroup Y) or higher in the MenACWY-D group, with GMT ratios between vaccine groups for serogroups A, C, Y, and W ranging from 1·9 (97·5% CI 1·5-2·3) for serogroup W to 2·5 (2·2-2·8) for serogroup A. NmCV-5 induced robust immune responses against serogroup X. Lot-to-lot consistency of NmCV-5 was found for all five serogroups, with 95% CIs for the GMT ratio for each pair of lots being between 0·5 and 2: the lowest lower bound and the highest upper bound of the 95% CI for the GMR between NmCV-5 lot A and lot B were 0·6 and 1·4, between lot A and lot C were 0·7 and 1·6, and between lot B and lot C were 0·8 and 1·6, respectively, for any of the five serogroups. At least one solicited adverse event was reported by 527 (42·7%) of 1233 participants in the NmCV-5 group and 142 (34·9%) of 407 in the MenACWY-D group. No serious adverse events occurred that were determined to be causally related to vaccination. NmCV-5 was non-inferior to MenACWY-D in terms of seroresponse and GMTs, was safe, and demonstrated lot-to-lot consistency. NmCV-5 is prequalified by WHO and was rolled out in the African meningitis belt in April, 2024. Serum Institute of India.

Statewide Outbreak of Neisseria meningitidis Serogroup Y, Sequence Type 1466 - Virginia, 2022-2024.

Invasive meningococcal disease (IMD) is a severe illness that can have devastating effects; outbreaks are uncommon in the United States. Vaccination is the preferred control measure for IMD outbreaks when a defined population at risk (e.g., college students or persons experiencing homelessness) can be identified. In August 2022, the Virginia Department of Health (VDH) began investigating an IMD outbreak in Virginia's Eastern Health Planning Region, prompted by the detection of four confirmed cases within 8 weeks. Clinical isolates available from three cases were characterized as Neisseria meningitidis serogroup Y, sequence type 1466. A subsequent statewide investigation identified 36 genetically related cases, including seven deaths (case fatality rate=19.4%) as of March 1, 2024. A majority of patients (63.9%) were in an age group (30-60 years) not generally considered at increased risk for IMD; 78.0% were non-Hispanic Black or African American. No common exposures, affiliations, or risk factors were identified, and a defined population could not be identified for vaccination. VDH recommended quadrivalent (serogroups A, C, W, and Y) meningococcal conjugate vaccination of a subset of close contacts of patients based on IMD risk factors and age range similar to that of patients with identified cases. IMD outbreaks might affect populations without established IMD risk factors. Lack of a well-defined population at risk might prompt exploration of novel control strategies, such as selective vaccination of close contacts.

Initial Experiences with Invasive Meningococcal Disease: Insights from Survivors and Their Caregivers.

Invasive meningococcal disease (IMD) has a low incidence but is a life-threatening illness with a 10-15% mortality rate. Even with timely treatment, survivors may experience acute and long-term health complications. While meningococcal vaccines are recommended for adolescents and young adults in the USA, vaccination coverage remains uneven across serotypes. This study investigated the physical, social, psychological, and economic burden of IMD on survivors and their caregivers in the USA during the acute phase (Part1, presented in this manuscript) and the long-term phase (Part2, presented in a separate manuscript) of IMD. This study implemented a non-interventional, mixed-methods approach using a bespoke survey and qualitative interviews (designed on the basis of a preliminary conceptual model of IMD) with US survivors and their caregivers. A total of 11 survivors (1 adolescent, 10 adults) and 3 caregivers participated in the study. Survivors contracted IMD during infancy (n = 2), childhood (n = 3), or adulthood (n = 6), and often described leading healthy lives pre-IMD. At IMD onset, interactions with the healthcare system impacted participants' experiences; confusion and care delays were common, and procedures were often invasive (e.g., amputations). Survivors commonly experienced symptoms including skin rash (7/11), fever (6/11), and unconsciousness (6/11), consistent with caregivers' reports. Survivors able to report on the short-term impacts of IMD (n = 9) described functional limitations (9/9), emotional impacts (6/9) such as fear and trauma, and school (6/9), work (4/9), and financial (5/9) challenges. Caregivers also experienced emotional impacts (3/3) and family (2/3), work (3/3), and financial (3/3) impacts during the acute phase. IMD places a significant humanistic burden on survivors and their caregivers during the acute phase. Results from Part1 of this study indicate a need for increased disease awareness and healthcare provider education, expeditious diagnosis, and improved access to prevention methods such as available meningococcal vaccines. A video abstract is available with this article. Video abstract (MP4 1,24,432kb).

Analytical Challenges in Novel Pentavalent Meningococcal Conjugate Vaccine (A, C, Y, W, X)

Multivalent meningococcal conjugate vaccines are a significant focus for the scientific community in light of the WHO’s mission to defeat meningitidis by 2030. Well-known meningococcal vaccines such as MenAfriVac, Nimenrix, Menveo, and MenQuadfi are licensed in various parts of the world and have been successful. Recently, the World Health Organization (WHO) qualified MenFive (meningococcal A, C, Y, W, and X) conjugate vaccine, further enhancing the battery of vaccines against meningitis. The antigenic nature of the current and new serogroups, the selection of carrier proteins, and the optimal formulation of these biomolecules are pivotal parameters for determining whether a biological preparation qualifies as a vaccine candidate. Creating appropriate quality control analytical tools for a complex biological formulation is challenging. A scoping review aims to identify the main challenges and gaps in analyzing multivalent vaccines, especially in the case of novel serogroups, such as X, as the limited literature addresses these analytical challenges. In summary, the similarities in polysaccharide backbones between meningococcal serogroups (C, Y, W sharing a sialic backbone and A, X sharing a phosphorous backbone) along with various conjugation chemistries (such as CNBr activation, reductive amination, CDAP, CPIP, thioether bond formation, N-hydroxy succinimide activation, and carbodiimide-mediated coupling) resulting into a wide variety of polysaccharide -protein conjugates. The challenge in analyzing carrier proteins used in conjugation (such as diphtheria toxoid, tetanus toxoid, CRM diphtheria protein, and recombinant CRM) is assessing their purity (whether they are monomeric or polymeric in nature as well as their polydispersity). Additional analytical challenges include the impact of excipients, potential interference from serogroups, selection and establishment of standards, age-dependent behavior of biomolecules indicated by molecular size distributions, and process-driven variations. This article explains the analytical insights gained (polysaccharide content, free saccharide, free proteins, MSD) during the development of the MenFive vaccine and highlights the crucial gaps and challenges in testing.

Post-COVID-19 Vaccination Meningitis and Meningoencephalitis: A Systematic Review of Case Series and Case Reports.

Meningitis and meningoencephalitis, as inflammatory diseases of the brain parenchyma, are serious events reported sporadically after coronavirus disease 2019 (COVID-19) vaccination. However, there is a lack of systematic reviews consolidating these reported cases. By using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive search was conducted across PubMed, Scopus, Embase, and Web of Science databases. All case reports and series discussing the emergence of meningitis and meningoencephalitis after COVID-19 vaccination were included and evaluated using the Joanna Briggs Institute critical appraisal tool. Out of 967 records, 27 studies with 31 patients were eventually included. The most commonly reported symptoms were headaches and fever. About one-third of the patients exhibited positive meningeal signs. Most of the findings in the computed tomography scans and magnetic resonance images revealed no significant changes or enhancement in the leptomeninges. Cerebrospinal fluid analysis dominantly suggested aseptic meningitis, and about 80.6% of the patients experienced a full recovery. After a detailed review of the reported cases, further research is needed to establish a definitive correlation between meningitis and COVID-19 vaccination on a larger scale.

Yellow Fever Vaccine-Associated Neurotropic Disease: A Case Report Of A 9-Month Old Infant And Review Of Literature

Introduction Yellow fever vaccine-associated neurotropic disease (YEL-AND) is a rare and serious complication following vaccination with the 17D live attenuated yellow fever vaccine. Cases of YEL-AND present as acute inflammatory demyelinating polyneuropathy, acute disseminated encephalomyelitis, and meningoencephalitis and encephalitis. To date, only a few cases have been reported in the literature in children. Methods/Subject We present the case of a 9-month-old male who developed YEL-AND. He suffered "3 episodes of unprovoked generalized tonicclonic seizure," the first occurring within 2 hours of receiving a dose of the Yellow Fever vaccine, Measles, and Meningococcal vaccines. He was lethargic for 28 hours and had intermittent inconsolable cries for 48 hours, low-grade fever, and loss of motor milestones (sitting and standing). Available laboratory investigations and neuroimaging ruled out other possible causes. He was treated with anticonvulsants and IV Methylprednisolone and made a significant recovery and was discharged on the sixth day and has remained stable on follow-up. His clinical presentation, neuroimaging, and challenges in his management are discussed in this case report. Conclusion The licensed Yellow fever vaccines are safe, effective for the prevention of Yellow fever, and highly recommended, however, it is not completely devoid of serious adverse reactions. This case highlights a possibility of a very early onset of YEL-AND in children and should be suspected in individuals with a temporal relationship of symptom onset to vaccination.

Incidence of Relapses After Meningococcal Vaccination in Clinical Trials of Eculizumab and Ravulizumab in Anti-Aquaporin-4 Antibody-Positive (AQP4-Ab+) Neuromyelitis Optica Spectrum Disorder (NMOSD)

Incidence of Relapses After Meningococcal Vaccination in Clinical Trials of Eculizumab and Ravulizumab in Anti-Aquaporin-4 Antibody-Positive (AQP4-Ab+) Neuromyelitis Optica Spectrum Disorder (NMOSD)

Inequalities in the risk and prevention of invasive meningococcal disease in the United States - A systematic literature review.

Vaccination remains the most effective strategy to prevent invasive meningococcal disease (IMD), with MenACWY, MenB and MenABCWY recommended for adolescents/young adults in the United States (US). However, vaccination coverage remains suboptimal, which could be related to population inequalities. To understand the impact of IMD risk, prevention and control inequalities, a global systematic literature review (Medline, Embase, 2012-2022) was conducted on individual, socioeconomic, and environmental inequalities associated with IMD risk, prevention and control in all ages. Studies on IMD risk (n = 15) and prevention (n = 14) inequalities were identified. IMD incidence proportions were higher in Medicaid versus commercially insured populations, and IMD mortality was higher in poorer neighborhoods. White adolescents, adolescents from lower income families, and with lower maternal education were more likely to receive MenB vaccination; while Black and Hispanic adolescents, and adolescents with higher family incomes, were more likely to receive MenACWY vaccination. Meningococcal vaccination was associated with being up-to-date with other vaccinations, having multiple healthcare/well child visits, having a pediatrician as healthcare provider (HCP), and attending private facilities; while being uninsured was associated with lower vaccination. States with a MenACWY vaccination mandate and higher pediatrician-to-children ratios had higher vaccination rates. Important inequalities were due to individual differences, socioeconomic, and environmental factors. IMD prevention is suboptimal, especially among adolescents/young adults. To improve health equity, health policy makers could ameliorate meningococcal vaccination coverage across the US, with simplified and stronger meningococcal vaccine recommendations from public health authorities, and initiatives to enhance parental/patient and HCP knowledge of IMD and vaccine recommendations.

Meningococcal Carriage in Children with Atypical Hemolytic Uremic Syndrome Receiving Eculizumab Therapy.

Eculizumab is a first-line treatment for atypical hemolytic uremic syndrome (aHUS), and patients undergoing eculizumab therapy may become more susceptible to infection caused by Neisseria meningitidis (Nm). While meningococcal vaccination is required for patients undergoing eculizumab therapy, there is limited knowledge about meningococcal carriage in children with aHUS. We aimed to evaluate (1) the prevalence of Nm carriage, (2) serogroup distribution, and (3) the immunization status of children undergoing eculizumab treatment for aHUS. The Meningo-aHUS study is a prospective, multi-center study evaluating meningococcal carriage in children and adolescents in Türkiye receiving eculizumab for aHUS. We noted the age, gender, daycare, school, or university attendance, passive smoking status, previous infection and antibiotic use, and previous immunization history, including meningococcal vaccines, from the medical records of those children with aHUS. We collected nasopharyngeal samples, tested them for Nm using real-time polymerase chain reaction, and performed a serogroup analysis on the positive samples. We collected nasopharyngeal samples from 62 children with aHUS. Out of 62 children, 61 (98.4%) had received at least one dose of the meningococcal vaccine. The median time since the last meningococcal vaccine dose was 15 months (1-59 months). We detected meningococcal carriage in three (4.8%, 95% CI 1.0-13.5) children, and all three strains were non-groupable (NG). No other serogroups were detected. Almost all the children received their risk-group meningococcal immunization, including booster doses. A 4.8% of children with aHUS carried NG meningococci and, no vaccine serogroups were detected. Patients treated with eculizumab remain profoundly susceptible to IMD due to these NG meningococcal strains. The occurrence of breakthrough cases and carriage of Nm, especially NG strains, highlights the significance of maintaining a state of constant alertness, promptly seeking medical attention, and swiftly treating any symptoms that align with IMD, regardless of their vaccination status or antibiotic prophylaxis.

Health Technology Assessment of Vaccines in Italy: History and Review of Applications

Background/Objectives. Many vaccines have been developed in recent decades, and many more will be available in the future. When new safe and effective vaccines are available, decision-makers must extensively assess them before including them in the national immunization plan and issuing recommendations. The Health Technology Assessment (HTA) could be an objective, transparent, and comprehensive approach to guiding the decision-making process for the use of vaccines. Objectives and Methods. The aim of this study was to review the indications for HTA use contained in Italian institutional documents on vaccination, namely the National Immunization Plans (NIPs) and available full Italian HTA reports on vaccines, assessing their availability at the time of national recommendations’ introductions. Results. HTA has been recognised as an eligible approach to deciding upon the introduction of vaccines through the NIPs of 2012–2014 and 2017–2019, and the last NIP, of 2023–2025, highlights the lack of funding dedicated to the production of independent HTA reports that can be used for issuing recommendations. In 2007–2023, twenty full HTA reports on vaccines were published in Italy: eight reports on influenza vaccines, five on Human Papilloma Virus (HPV), three each on meningococcal and pneumococcal vaccines, and one on rotavirus vaccine. HTA was applied with different purposes, namely the evaluation of new vaccines or their re-assessment, but it was not always timely with respect to both the marketing authorisation and the issuing of national recommendations for use. Conclusions. As HTA can be considered the best tool to disentangle the overall value of vaccines, it would be desirable for it to be used more and more to provide the evidence for efficient resource use. This calls for action to improve the transfer of HTA results to decision-makers, to try to fill the gap between research and decision and foster evidence-based recommendations.

Meningococcal vaccine Bexsero elicits a robust cellular immune response that targets but is not consistently protective against Neisseria gonorrhoeae during murine vaginal infection.

Retrospective epidemiological studies suggest that the licensed serogroup B meningococcal vaccine 4CMenB (Bexsero) provides some protection against the closely related pathogen Neisseria gonorrhoeae in humans. This result has been replicated in murine models of gonococcal colonization, with a gonococci-reactive humoral response and more rapid clearance of vaginal infection. However, immunization with Bexsero consistently elicits a robust humoral response but does not protect all individuals, so the correlates of protection remain undefined. Herein, we exploit the fact that Bexsero promotes clearance in only a subset of immunized mice to perform a broad analysis of the adaptive response in animals that are or are not protected. We observe that Bexsero vaccination induces high levels of anti-neisserial antibodies in both serum and the vaginal lumen, and a robust cellular response highlighted by an increase in both conventional naive and memory populations as well as unconventional lymphocyte subsets. Multiplex and flow cytometry results show that Bexsero vaccination generates a robust, multi-faceted cytokine response that spans numerous T cell subsets (TH1, TH2, Treg and TH17 responses) and that non-T non-B lymphocytes play an important role in this response, as indicated by an unbiased principal component analysis. Together, this work provides the first comprehensive analysis of the robust humoral and complex cellular response to Bexsero so as to reveal the effector mechanisms that may contribute to immunity against vaginal gonococcal infection.

June 2024 ACIP Meeting Update: Influenza, COVID-19, RSV, and Other Vaccines.

The Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts that provides advice to the Centers for Disease Control and Prevention, normally meets 3 times per year to develop US vaccine recommendations. The ACIP met June 26 through 28, 2024. This update summarizes the proceedings of this meeting, with an emphasis on topics that are most relevant to the pediatric population. Major updates for pediatric clinicians include COVID-19 and influenza vaccine recommendations for the 2024 to 2025 season, meningococcal vaccination considerations, information regarding preferred Haemophilus influenzae type B containing vaccines for American Indian and Alaskan Native infants, and updates regarding implementation and effectiveness of RSV immunization in pregnant people and infants.

Economic evaluation on meningococcal vaccination strategies among children under nine years of age in Zhejiang province, China.

Meningococcal vaccination in Chinese national immunization program (NIP) includes polysaccharide vaccine against Neisseria meningitidis serogroup A (MPV-A) and polysaccharide vaccine against Neisseria meningitidis serogroup A and C(MPV-AC). This study aimed to assess the cost-effectiveness of an alternative strategy using polysaccharide conjugate vaccine against Neisseria meningitidis serogroup A,C,W,Y(MCV-ACWY) and polysaccharide vaccine against Neisseria meningitidis serogroup A,C,W,Y(MPV-ACWY). From a societal perspective, we constructed a decision tree-Markov model to simulate the economic and health consequences of meningococcal disease in a 2023 birth cohort with the current meningococcal vaccination strategy and the alternative. Parameters of epidemiology, vaccine efficacy, cost, and utility were extracted from database and previous literatures. The sensitivity analysis was implemented to evaluate the robustness of the model. Compared to the current practice, the alternative strategy could avoid 513 meningococcal disease cases, 53 sequelae and 47 deaths. The ICER was estimated at $16899.81 /QALY, under the threshold of one time of the GDP per capita of Zhejiang province in 2023. The incidence of meningococcemia, the incidence of meningococcal meningitis, the case fatality of meningococcemia, the vaccine efficacy of MCV-ACWY and the price of MCV-ACWY would influence the cost-effectiveness of the meningococcal vaccination strategies. At the threshold, the probability of cost-effectiveness was 14.76% for the current strategy and 55.98% for the alternative strategy, respectively. The current meningococcal vaccination strategy had effectively prevented meningococcal disease at a low cost, but with limited serogroup coverage. Strategy using MCV-ACWY and MPV-ACWY could increase health benefits at a substantial cost at a cost-effective manner.

A perspective on the novel pentavalent Men5CV (NmCV-5) meningitis vaccine and Nigeria's pioneering rollout campaign.

The burden of meningitis poses great challenges for neurology and global health, manifesting with a range of symptoms from mild fever and headaches, to severe long term complications such as paralysis and cognitive impairment.. Unfortunately, those living in endemic regions, especially survivors, are often confronted with the harsh reality of reduced quality of life as measured by disability-adjusted life years. Meningitis is one of the leading causes of mortality and morbidity, especially in the meningitis belt of sub-Saharan Africa, with a recorded disease burden of over 2.5 million cases globally and children under five disproportionately impacted. This paper examines the global burden of meningitis, exploring its prevalence and impact across different regions. It further analyzes the evolution of vaccination strategies for meningitis prevention, emphasizing the recent development and introduction of the novel Men5CV meningococcal conjugate vaccine. Recurrent meningitis outbreaks across the meningitis belt have resulted in significant mortality over decades. A major turning point in the fight against the serogroup A epidemic was the development of the MenAfriVac vaccine, which resulted in declining cases. However, serogroups C, W, and X continue to pose problems. The novel pentavalent (Men5CV) vaccine has emerged as a remarkable advancement in the fight against meningitis, with its safety and effectiveness against a variety of serogroups, including the elusive serogroup X, demonstrated in clinical trials. Its pre-qualification by the World Health Organization (WHO), and subsequent recommendation for incorporation into routine immunization programs issued a new era with the potential for meningitis eradication. Nigeria now sets a benchmark for other nations in the meningitis zone, becoming the first country in the world to roll out the new Men5CV vaccines. Funding from organizations like Gavi, the Vaccine Alliance, highlights the importance of coordinated international efforts aligned with the WHO's roadmap for meningitis elimination by 2030. Stakeholder involvement, extensive immunization campaigns, and a strong healthcare infrastructure are all practical recommendations for public health integration.

Understanding the Sequelae of Invasive Meningococcal Disease in the United States.

Invasive meningococcal disease (IMD) is an uncommon but serious and potentially fatal condition that can result in reduced life expectancy and a broad spectrum of sequelae, many of which may be lifelong and devastating for those who survive the acute disease period. In the United States of America (USA), vaccination is available against the five meningococcal serogroups (A, B, C, W, and Y), but meningococcal vaccination rates among healthy USA adolescents and individuals at high risk because of medical conditions are low, rendering them vulnerable to IMD and its sequelae. Despite the severity of the disease, the clinical impact and rates of IMD sequelae in the USA are poorly understood, as USA-specific data are limited, and the methodology of existing research is heterogenous. This commentary presents clinical experts' perspectives on IMD sequelae based on the available published evidence and direct clinical experience. Among sequelae previously identified in a global systematic literature review, 16 conditions were considered as related to IMD by the present authors. These sequelae include short- and long-term physical, neurological, and emotional consequences that impose a substantial humanistic burden on survivors and their caregivers and result in considerable healthcare and societal costs. This commentary highlights existing knowledge gaps concerning IMD sequelae, including the unclear relationship between IMD and mental health disorders, the contribution of sequelae to the disease burden, prevalence of late-onset sequelae among survivors, and timing of the development of sequelae in different age groups. Addressing these knowledge gaps can inform decisions regarding clinical management in the post-acute period and help quantify the impact of prevention through meningococcal vaccination.