Search Results (61)

Background: Invasive meningococcal disease (IMD) remains a rare but severe condition associated with high mortality and a significant risk of long-term sequelae. Despite global vaccination efforts, the epidemiology of Neisseria meningitidis continues to evolve, with serogroup B (MenB) representing the predominant cause of IMD in many high-income countries. Methods: This consensus document reviews current evidence on MenB epidemiology and the role of the multicomponent meningococcal serogroup B vaccine (4CMenB), with a focus on immunogenicity, strain coverage, real-world effectiveness, and remaining challenges. Results: Protein-based MenB vaccines have overcome the limitations of polysaccharide approaches, demonstrating robust immunogenicity across age groups. Real-world data confirm substantial vaccine effectiveness, particularly in infant immunization programs and outbreak settings, with significant reductions in disease incidence. For example, in England in the 3 years after vaccine introduction, MenB IMD incidence declined by 75% in immunized infants compared to unvaccinated controls. Adjusted vaccine efficacy was 52.7% after the two-dose primary series and 59.1% following the booster dose, highlighting the contribution of the booster. However, protection is influenced by antigenic variability among circulating strains, resulting in incomplete and geographically variable coverage. In addition, antibody waning over time and the limited impact on nasopharyngeal carriage reduce the potential for long-term and indirect protection. These factors highlight the need to optimize vaccination strategies, including the timing of booster doses, particularly in adolescents, and the role of vaccination in different epidemiological contexts. In this regard, it is not precisely defined whether infants who were immunized in the first year of life need a booster dose in the preschool period, especially in countries with a high incidence of MenB disease. Moreover, it is not established whether and when adolescents who were vaccinated both in infancy and during the preschool period need a booster dose. Economic considerations and variability in national immunization policies further contribute to heterogeneity in vaccine implementation. Emerging evidence suggests possible cross-protection against other meningococcal serogroups and Neisseria gonorrhoeae, although findings remain inconsistent across different risk groups and do not allow us to recommend 4CMenB vaccine beyond MenB IBD prevention. Conclusions: 4CMenB is an effective tool for preventing MenB IMD, although further studies are needed. Future strategies should prioritize age-targeted boosting and enhanced genomic surveillance to maximize impact. Full article

Background: In March 2026, a meningococcal cluster centred on the University of Kent, England, caused two deaths and resulted in over 20 reported cases within the first week, including confirmed and suspected invasive cases. Subsequent UKHSA updates in early April 2026 reported 21 laboratory-confirmed MenB cases (18 linked to the outbreak strain) and two deaths, with the outbreak subsequently spreading to a second Canterbury university, Canterbury Christ Church University, and confirmed as Neisseria meningitidis serogroup B (MenB). Sub-Saharan Africa (SSA) bears a disproportionate global burden of meningococcal disease, yet university settings remain a critically understudied outbreak amplifier. This narrative review extracts epidemiological and policy lessons from the Kent event and applies them to the SSA context. Methods: We conducted a narrative review following the SANRA criteria, searching PubMed, Embase, Scopus, Google Scholar, and African Journals Online (2000–2026), with supplementary grey literature retrieved from World Health Organisation (WHO), Africa Centre for Disease Control, and United Kingdom Health Security Agency (UKHSA). Outbreak data were drawn from official UKHSA public-health statements (grey literature, archived), the University of Kent communications, and peer-reviewed expert commentary. Results: The Canterbury outbreak exposed six reproducible vulnerabilities: unprotected serogroup circulation (confirmed MenB, not covered for the current university-age cohort), nightlife-linked transmission amplification, delayed serogroup identification, poor student symptom-recognition, inadequate institutional response capacity, and, critically, multi-institutional spread via shared nightlife venues (confirmed extension to Canterbury Christ Church University within five days). Each vulnerability is demonstrably more severe in SSA universities, which face a broader multi-serogroup threat environment (NmA, B, C, W, X), virtually no university-entry vaccination requirement, and critical evidence gap of campus-specific meningococcal evidence in the published literature. Conclusions: This review proposes a five-pillar preparedness framework for SSA tertiary institutions, derived from a synthesis of the Kent outbreak and broader epidemiological evidence, intended to inform policy discussion and future research. Moreover, these should be embedded within a broader age-linked prevention strategy that begins before university entry, particularly during the transition into secondary school in high-risk settings. Priority measures include meningococcal vaccination at key educational transition points, prophylactic antibiotic pre-positioning, serogroup-capable surveillance, symptom-recognition training, and pan-continental alert A predominantly reactive response may carry substantial risk in SSA settings. Full article

Background/Objectives: Meningococcal disease is primarily caused by serogroups A, B, C, W, and Y. Current US vaccination recommendations include routine serogroup A/C/W/Y (MenACWY) vaccination (ages 11–12 and 16 years) and a two-dose, 0-, 6-month MenB vaccination series (age 16–23 years) based on shared clinical decision-making. Administration of the first-in-class Pfizer pentavalent MenABCWY vaccine (Penbraya^TM), which received US licensure in 2023 as a two-dose, 0-, 6-month series, is endorsed when the MenACWY and MenB vaccines are recommended at the same visit. This study evaluated the immunogenicity and safety of two extended two-dose schedules of MenABCWY in healthy adolescents. Methods: In this observer-blinded, phase 2b study (ClinicalTrials.gov, NCT04440176; 19 June 2020), 309 healthy 11- to 14-year-olds were randomized 1:1 to receive a 0-, 36-month or 0-, 12-month Pfizer MenABCWY schedule, which more closely aligns with current US MenACWY vaccination recommendations. Endpoints included serum bactericidal assay using human complement seroprotection rates (titers ≥ 1:8 or ≥1:16, depending on strain), seroresponse rates (≥4-fold increase from baseline titer), and geometric mean titers (GMTs). Safety was also assessed. Results: One month after the second Pfizer MenABCWY dose, serogroup A/B/C/W/Y seroprotection rates were 100% for the 0-, 36-month schedule and 96.6–100% for the 0-, 12-month schedule; seroresponse rates were 100% and 92.9–100%, respectively. GMTs generally trended higher with the 0-, 36-month schedule. Seroprotection rates through 24 months after the second dose of the 0-, 12-month schedule were 44.0–75.0% for serogroup B and 88.9–100% for serogroup A/C/W/Y). No safety issues were identified. Conclusions: These data support Pfizer MenABCWY dosing flexibility and utility within the current or possible future US meningococcal vaccination framework. Full article

Background: Invasive meningococcal disease (IMD) caused by Neisseria meningitidis remains a major public health concern due to its severity, lethality, and long-term sequelae. To address the rise in serogroups W and Y in Spain, the Community of Madrid implemented a catch-up campaign in 2019–2021, targeting adolescents (ages 13–18) alongside routine tetravalent meningococcus vaccine (MenACWY) at age 12. This study evaluated MenACWY catch-up vaccination uptake in routine practice by describing vaccine coverage, temporal trends, and associated factors in adolescents born between 2001 and 2006. Methods: A population-based cross-sectional study was conducted using data from the Community of Madrid’s vaccination registry (SISPAL Vacunas). Vaccination coverage was calculated for adolescents with at least one recorded MenACWY dose from age 10 onwards. Temporal trends were analyzed by birth cohort and calendar time, and multivariable logistic regression models were used to identify factors associated with vaccination uptake. Results: Among 424,059 adolescents, overall vaccination coverage by December 2021 was 63.8%, ranging from 54.4% to 78.2% across birth cohorts. Coverage was highest in the 2006 cohort, likely due to co-administration with the tetanus and diphtheria (Td) booster. A slightly higher uptake was observed among females and adolescents with chronic conditions, while foreign-born adolescents consistently showed lower coverage. COVID-19 disruptions led to temporal variability, with sharp declines during lockdowns and partial recoveries thereafter, with persistent sociodemographic differences in uptake. Conclusions: By December 2021, coverage was incomplete, with marked variability across birth cohorts. Higher uptake was observed when vaccination was integrated into routine visits, while persistent sociodemographic disparities remained evident. These observational findings are consistent with the programmatic value of combined catch-up and routine strategies and the need for targeted actions to ensure equitable MenACWY coverage. Full article

Invasive meningococcal disease (IMD) is classically associated with meningitis and septic shock, but an increasing proportion of cases present with atypical, extra-meningeal manifestations. Following the COVID-19 pandemic, major epidemiological shifts have occurred in France, including a rebound in IMD incidence and changes in circulating serogroups and clonal complexes. We conducted a nationwide retrospective study including all laboratory-confirmed IMD cases analysed by the French National Reference Centre between July 2014 and June 2025. Clinical presentations were coded as non-exclusive entities. Associations with age, serogroup, clonal complex, antimicrobial susceptibility and early mortality (≤72 h) were assessed using descriptive analyses and multivariable logistic regression models. Among 4328 IMD cases, sepsis/shock (61.1%) and meningeal involvement (54.9%) predominated, while atypical forms were frequent, including bacteraemic pneumonia (7.7%), abdominal presentations (8.0%) and arthritis (6.0%). Bacteraemic pneumonia was strongly associated with older age and serogroups W and Y, whereas abdominal forms predominated in adolescents and young adults and were independently associated with serogroups W and Y and clonal complex (cc) cc11. Abdominal presentations were independently associated with early mortality (adjusted odds ratio [aOR] 2.40) but not meningococcal pneumonia. Abdominal presentations were associated with serogroup W (aOR 2.27; 95% CI 1.35–3.83) and serogroup Y (aOR 2.92; 95% CI 1.79–4.75) and with cc11 (aOR 1.77; 95% CI 1.07–2.94). In contrast, cc23 was associated with lower odds of abdominal involvement (aOR 0.42; 95% CI 0.25–0.70). Overall, atypical presentations now represent a substantial proportion of IMD in France and are strongly shaped by age and meningococcal lineage. These findings highlight diagnostic challenges, prognostic heterogeneity and the need for continued integrated clinical, microbiological and genomic surveillance in the context of evolving vaccination strategies. Full article

Introduction: Despite the advances in its prevention, invasive meningococcal disease (IMD) remains a serious health problem worldwide due to its high morbidity and mortality, including in Romania, with 22% mortality rate. The objectives were to describe the trends of IMD cases admitted to a tertiary care hospital in Romania, over 24 years, and the case fatality rate (CFR) by age, year of admission, and Neisseria meningitidis serogroups. Materials and Methods: A retrospective study was conducted in IMD patients admitted to the National Institute for Infectious Diseases “Prof. Dr. Matei Bals”, Bucharest, Romania, between 2001 and 2024. Results: A total of 256 IMD patients were admitted, 171 under fourteen years, out of which 75 were infants. Most cases were reported before 2008. The case distribution showed 90 patients (35%) with meningitis, 84 (32%) with meningococcaemia, and 82 (32%) with an association of both. Serogroup B was the most frequently and steadily found (58 cases). The overall CFR was 12%. CFR was highest in infants younger than 6 months (19%) and meningococcaemia cases (29%). Conclusions: In our study, IDM had the highest frequency and CFR in infants and meningococcaemia cases. The trends showed a decline in cases after 2008. Serogroup B was the most prevalent and stable strain over 24 years. Full article

Background: During the COVID-19 pandemic, reductions in cases of bacterial diseases transmitted via the respiratory route were reported by the Invasive Respiratory Infection Surveillance Consortium. Here, we evaluate the epidemiology of invasive meningococcal disease (IMD) in Argentina, Brazil, Chile, and Colombia during and after the COVID-19 pandemic. Methods: The epidemiology of meningococcal disease was reviewed in selected South American countries through 2023 from publicly available national surveillance system databases. Results: The incidence of IMD decreased substantially in 2020 in Argentina, Brazil, Chile, and Colombia and was followed by a trend of increased disease. Similarly to observations in several European countries, the post-pandemic rebounds in cases of IMD in the four South American countries included in this analysis were mainly caused by serogroup B, that became one of the predominant serogroups causing IMD in all four countries. Conclusions: Enhanced surveillance of IMD, including genomic characterization of strains, is needed to inform public health policymakers and guide future vaccination strategies in the region. Full article

Laboratory confirmation of invasive meningococcal disease (IMD) relies on detection of Neisseria meningitidis in a biological specimen. Clinical management guidelines for patients presenting with signs and/or symptoms of meningitis and encephalitis emphasize the need for appropriate specimen collection for laboratory testing. To explore the potential for IMD under-diagnosis, we reviewed medical records of patients admitted with signs and/or symptoms of meningitis or encephalitis at five hospitals in Louisville, Kentucky, in 2014 to 2023. Among 675 patients admitted with meningitis and/or encephalitis with cerebrospinal fluid (CSF) cultures who received antibiotics, 300 (44.4%) received antibiotics before CSF collection. Among 431 with blood cultures who received antibiotics, 133 (30.9%) received antibiotics before blood collection. Among 751 patients with CSF collected, 651 (86.7%) CSF specimens were tested using polymerase chain reaction (PCR) for N. meningitidis detection. No blood specimens were PCR-tested. These findings indicated that current standard-of-care practices may lead to IMD under-diagnosis. Since public health surveillance relies on IMD laboratory diagnosis, these findings highlight the potential for under-ascertained IMD by surveillance. Full article

Background: Meningococcal B (MenB) vaccination offers protection against invasive meningococcal disease and moderate cross-protection against gonorrhea. However, little is known about coverage and behavioral correlates among men who have sex with men (MSM) in China. This study assessed self-reported MenB vaccination uptake and its associations with sociodemographic and behavioral factors. Methods: We conducted a nationwide cross-sectional survey among 1022 MSM recruited via community-based organizations and online platforms. Vaccination status and recent sexual behaviors were self-reported. Logistic regression identified correlates of uptake, and latent class analysis (LCA) examined behavioral profiles. Results: Participants had a mean age of 29.6 years; most were unmarried (87.7%) and nearly 90% had a college degree or above. Overall, 21.7% reported receiving MenB vaccination. Uptake was positively associated with condomless anal intercourse (aOR = 1.57, 95% CI: 1.08–2.31), group sex (occasionally: aOR = 1.63, 95% CI: 1.01–2.64; frequently: aOR = 3.86, 95% CI: 1.85–8.04), and female partners in the past six months (aOR = 3.69, 95% CI: 2.25–6.10). MSM with multiple casual male partners were less likely to be vaccinated (aOR = 0.55, 95% CI: 0.32–0.93). LCA identified heterogeneous subgroups; notably, the “multi-partner and proactive” group, with high pre-exposure prophylaxis against HIV infection awareness and frequent STI testing, showed low uptake (13.4%). Conclusions: MenB vaccination coverage among MSM in China remained suboptimal. Uptake differed across behavioral subgroups, underscoring the need for stratified, context-specific strategies to inform future vaccine introduction. Full article

Background: Invasive meningococcal disease (IMD) is an uncommon but potentially life-threatening condition, resulting in life-long sequelae or death in up to 20% of cases. Most IMD cases are caused by Neisseria meningitidis serogroups (Men) A, B, C, W, X, and Y. The highest IMD incidence is among children < 5 years of age (YOA). We reviewed IMD epidemiology data and existing national immunization programs (NIP) in the Americas and identify unmet needs to decrease IMD burden in young children. Methods: Using national surveillance data and published literature from 2006 to 2024, we evaluated the IMD burden and national vaccination strategies for children < 5 YOA in the Americas, focusing on Canada, the United States, Brazil, Chile, Argentina. Results: The highest IMD incidence was among infants, followed by children 1–4 YOA, with MenB infections predominating in both age groups. Chile has both MenACWY (2014) and MenB (2023) infant vaccination in its NIP. Argentina and Brazil’s NIPs include MenACWY (2017) and MenC (2010) vaccinations for infants, respectively. In Canada, MenC (2002) vaccination is recommended at 1 YOA (replaced by MenACWY in 2024 in Manitoba); MenB vaccination is selectively recommended. In each country, the incidence of IMD caused by vaccine-preventable serogroups decreased following the introduction of the respective meningococcal vaccination in the NIP. Conclusions: Comprehensive meningococcal vaccination programs in the Americas have the potential to reduce the IMD burden in children < 5 YOA. National recommendations and NIPs could reduce IMD burden by offering equitable access to protection against IMD, aligning with the WHO roadmap to defeat meningitis by 2030. Full article

Background/Objectives: Meningococcal disease (MD) remains a significant public health concern worldwide. In Serbia, mandatory immunization against MD with the meningococcal polysaccharide vaccine (MenAC) for high-risk groups and international travelers was introduced in 2006. Since 2017, the polysaccharide vaccine has been replaced with the quadrivalent meningococcal conjugate vaccine (MenACWY). The aim of this study was to analyze long-term trends in incidence, age-specific patterns, seasonality, and lethality of invasive meningococcal disease (IMD) in the Autonomous Province of Vojvodina (AP Vojvodina), Serbia, over a 28-year period. Methods: A descriptive study analyzed all reported cases of IMD in AP Vojvodina, from 1997 to 2024. Data were obtained from the regional communicable disease surveillance system, based on mandatory hospital reporting and case classification according to national and WHO guidelines. Temporal, demographic, and clinical characteristics, along with disease outcomes, were analyzed. Results: From 1997 to 2024, 175 IMD cases were reported in AP Vojvodina. The annual incidence peaked in 1997 (1.24/100,000), with smaller surges in 2003 and 2005. Since 2006, coinciding with the introduction of immunization against MD, a sustained decline has been observed, with incidence rarely exceeding 0.30/100,000. A slight resurgence occurred in 2023–2024, with 13 cases reported. From 1997 to 2024, IMD in AP Vojvodina exhibited a clear seasonal pattern, with most cases occurring in winter and early spring, peaking in January (17%), March (12%), and February (11%), and the fewest cases occuring in the summer months. Throughout the study period, the highest IMD incidence rates were consistently observed among infants <1 year of age and children aged 1–4 years, with peaks of up to 22.9/100,000 and 16.0/100,000, respectively. Incidence was much lower in older age groups, especially adults. After a 2006 peak, rates declined across all ages, with a slight resurgence in 2023–2024 among children and adolescents. Children aged 1–4 years made up the largest share of IMD cases, peaking in January–March (45.1%). Half of the infant cases were recorded in October–November, while cases in older children, adolescents, and adults were fewer and showed varied monthly patterns, with small peaks in winter and early spring. During the 28-year study period, the highest IMD mortality rate was observed among infants <1 year of age (0.59 per 100,000 population), followed by children aged 1–4 years (0.32 per 100,000). Mortality rates declined progressively with increasing age, with the lowest rate recorded among individuals aged ≥40 years (0.01 per 100,000). Of the 175 IMD cases reported in AP Vojvodina (1997–2024), 21 were fatal (case fatality rate [CFR] = 12.0%). The CFR of IMD varied across age groups. The highest CFR was observed among individuals aged ≥40 years (21.4%), followed by the 5–9 years (17.4%) and <1 year (16.7%) age groups. None of the patients had been vaccinated against MD. Fatal outcomes were more common in children aged 1–4 years and among rural residents, though differences were not statistically significant (p > 0.05). Most deaths (57.1%) occurred in the first quarter of the year. A strong association was found between clinical form and outcome, with meningococcal sepsis being significantly more frequently associated with fatality than meningitis (p = 0.0002). Deaths were sporadic over time, with most occurring within 1–2 days of notification. All confirmed fatal cases were due to serogroup B. Conclusions: MD remains a rare yet serious public health threat in AP Vojvodina. Mortality rates indicate that the public health impact of this disease is greatest among the youngest age groups; however, the risk of death, i.e., disease severity, does not appear to be age dependent. The recent rise in cases, high fatality among sepsis patients, and absence of prior vaccination among all IMD cases highlight the need for enhanced surveillance, physician education, and consideration of introducing both MenACWY and MenB vaccines for high-risk groups. Full article

Background: Neisseria meningitidis B is one of the main causative pathogens of meningitis and other forms of severe meningococcal disease. In the past decade, meningococcal B vaccines have been developed to address this infection and its sequelae. Objective: This article aims to present an example of how the EU regulatory framework allowed the early authorisation of two life-saving vaccines initially based on immunogenicity surrogates of clinical evidence. This was subsequently followed by post-marketing surveillance providing real-world evidence to support their safety profile and impact on the paediatric population in the EU. Methods: We review the evidence supporting the initial regulatory approval of the vaccines, the confirmatory data demonstrating vaccine effectiveness post-authorisation, and the real-world impact of these vaccines on the paediatric population. Results: Two vaccines were approved in the EU for active immunisation to prevent IMD caused by MenB (4CMenB in 2013 and MenB-fHBP in 2017). Both marketing authorisations were based on immunogenicity data (efficacy studies were not feasible due to the rarity of the disease) and safety data generated from pre-authorisation studies. Additional pharmacovigilance activities to further investigate the safety profile and effectiveness studies were requested to be conducted after approval. Both the effectiveness and safety profile of the vaccines were confirmed by these data. Conclusions: This paper illustrates that the EU medicines regulatory framework and safety monitoring system are robust. By supplementing the initial evidence with post-authorisation studies, further effectiveness and safety data enabled regulators to confirm the positive benefit–risk of the vaccines without delaying their access to the people who need them. Full article

Background/Objectives: In France, non-pharmaceutical interventions (NPIs) implemented to control COVID-19 led to a significant decline in invasive meningococcal disease (IMD) cases. However, a rebound in cases, particularly for serogroups W and Y, was observed after the gradual lifting of NPIs, raising questions about an “immunity gap” due to reduced circulation of the bacteria. During the study period, vaccination against MenC was mandatory from 2018, and vaccination against MenB has been recommended since 2022. Methods: We conducted a retrospective seroepidemiological study using 166 normal sera collected between 2016 and 2024. Anti-Neisseria meningitidis IgG levels were quantified by ELISA using purified capsular polysaccharides for serogroups B, C, W, Y, and X. Samples were categorized into three periods: pre-NPIs (n = 72), during NPIs (n = 33), and post-NPIs (n = 61). Statistical comparisons were performed using Kruskal–Wallis tests for non-parametric data. Results: Our results show a significant decline in anti-serogroup B IgG antibody levels after the lifting of NPIs (p < 0.0001) in line with reduced circulation. Anti-serogroup C IgG antibody levels increased incrementally (p = 0.0003), particularly in those aged 1–4 years, likely reflecting a catch-up in anti-meningococcal C vaccination coverage. Anti-serogroup W IgG antibody levels remained stable, suggesting sustained circulation, but shifted to young children in the post-NPI period, potentially due to a genotypic shift. Anti-serogroup Y IgG antibody levels transiently increased significantly (p < 0.0001) during the NPI period but then decreased back after their lifting. Anti-serogroup X IgG antibody levels remained stable, consistent with its low prevalence and the absence of targeted vaccination. Full article

Background: The Spanish Interterritorial Council of the National Health System (a central government body) currently recommends vaccination against meningococcal serogroup C (MenC) at 4 and 12 months of age for prevention of invasive meningococcal disease (IMD). The Advisory Committee on Vaccines of the Spanish Association of Pediatrics (a professional medical association) and numerous Spanish regional bodies instead recommend quadrivalent vaccination against serogroups A, C, W, and Y (MenACWY) at 4 and 12 months of age. The central government and Spanish Association of Pediatrics also recommend MenACWY vaccination at 12 years of age. This study assessed the potential public health effects of replacing the MenC vaccination schedule with different MenACWY vaccination schedules in infants. Methods: Here, a static multi-cohort population model was used to evaluate potential effects on public health of IMD due to meningococcal serogroups C/W/Y, comparing MenC infant vaccination (reference strategy) against four different strategies including quadrivalent tetanus toxoid conjugate vaccine (MenACWY-TT; Nimenrix^®, Pfizer Europe MA EEIG, Brussels, Belgium) infant vaccination; all strategies included MenACWY-TT vaccination at 12 years of age. Results: The most effective strategy for infant vaccination was MenACWY-TT at 2, 4, and 12 months, preventing an estimated additional 103 IMD cases, 17 deaths, and 41 cases with long-term sequelae (LTS) versus the reference strategy in the base-case IMD incidence scenario. When strategies included a two-dose infant schedule, the earlier the infant MenACWY-TT vaccine was administered, the more additional cases, deaths, and cases with LTS were prevented (base-case and high-incidence scenarios). Conclusions: This analysis supports implementation of MenACWY-TT as a replacement for MenC vaccination. Full article

Background: Neisseria meningitidis (N. meningitidis) is a leading cause of acute meningitis and is classified into 13 serogroups, six of which are predominantly associated with invasive meningococcal disease. This study aimed to investigate the genotype, subgenotype, and antigenic profiles of N. meningitidis serogroup B strains isolated in Vietnam. Methods: Genotyping was performed on 106 N. meningitidis strains isolated from clinical samples from Vietnamese patients and nasopharyngeal swabs of healthy adolescents between 2019 and 2024. The genetic profiles, including the porA, porB, fetA, fHbp, abcZ, adk, aroE, fumC, gdh, pdhC, and pgm genes, were analyzed using Sanger sequencing and bioinformatic methods. Results: We found that 84.9% of the strains carried VR3 families 36 or 35-1, with VR1, VR2, and VR3 families 22-25, 14, and 36 being the most prevalent. Among the 106 serogroup B isolates, 20 variants of the porB allele 3 were identified, with porB 3-1212 being the most frequent (30.2%). Dominant PorB variable loops included L1.6, L4.5, L5.7, L6.6, and L7.13. fHbp variant group 2 was predominant (104/106 strains), and 12 FetA allele variants were identified, with F1-7 being the most common (47.2%). Three clonal complexes were identified, and clonal complex ST-32 was the most predominant. Fifty-five strains (51.9%) belonged to sequence types that have not yet been assigned to any clonal complexes, and 15 strains (14.1%) with allelic profiles were not assigned to STs. The 3-253 and 3-1212 alleles of porB, the F1-7 variant of FetA, the ST-44 and ST-1576 sequence types, and the ST-41/44 complex were observed more frequently in patients compared to asymptomatic carriers, suggesting their association with more virulence. Conclusions: This study showed a high genetic and antigenic diversity of N. meningitidis serogroup B isolates in Vietnam, with VR3 family 36 most common and porB 3-1212 as the predominant allele. fHbp variant group 2 and FetA allele F1-7 were most frequent. ST-32 was the dominant clonal complex, though many strains remained unassigned, highlighting the need for ongoing molecular surveillance. Full article