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Recently, a meningococcal vaccine for group B was approved and deployed into clinical practice. In this trial, the effect of widespread use of this vaccine on the nasopharyngeal carriage of meningococcus group B was assessed in more than 24,000 adolescents in Australia.

Neisseria meningitidis is a common commensal bacterium of the nasopharynx that can cause invasive meningococcal disease (IMD). In comparison, N. gonorrhoeae is always a pathogen usually limited to mucosal sites. However, increased evidence for overlapping clinical syndromes is emerging. We compared N. meningitidis samples from a urogenital outbreak in Australia with sequences from the United States and other countries. We conducted phylogenetic analyses to assess relatedness and examine for genomic changes associated with meningococcal adaptation; we collated a total of 255 serogroup Y (MenY), sequence type (ST) 1466 isolate assemblies. Most urogenital isolates originated from Australia; those isolates formed a distinct clade, most closely related genomically to recent US IMD isolates. No specific genomic changes suggested niche adaptation or associated clinical manifestations. The MenY ST1466 N. meningitidis isolates circulating in Australia and the United States are capable of causing both urethritis and invasive meningococcal disease.

Meningococci spread via respiratory droplets, whereas the closely related gonococci are transmitted sexually. Several outbreaks of invasive meningococcal disease have been reported in Europe and the United States among men who have sex with men (MSM). We recently identified an outbreak of serogroup C meningococcal disease among MSM in Germany and France. In this study, genomic and proteomic techniques were used to analyze the outbreak isolates. In addition, genetically identical urethritis isolates were recovered from France and Germany and included in the analysis. Genome sequencing revealed that the isolates from the outbreak among MSM and from urethritis cases belonged to a clade within clonal complex 11. Proteome analysis showed they expressed nitrite reductase, enabling anaerobic growth as previously described for gonococci. Invasive isolates from MSM, but not urethritis isolates, further expressed functional human factor H binding protein associated with enhanced survival in a newly developed transgenic mouse model expressing human factor H, a complement regulatory protein. In conclusion, our data suggest that urethritis and outbreak isolates followed a joint adaptation route including adaption to the urogenital tract.

Invasive meningococcal disease (IMD) caused by Neisseria meningitidis can result in life-threatening meningitis and septicaemia. There are twelve serogroups of N. meningitidis, but most cases of IMD are caused by serogroups A, B, C, W, X and Y. In Europe, serogroup B (MenB) accounts for 51 % of documented cases as recently reported by the European Centre for Disease Prevention and Control (ECDC). As a major cause of IMD, genomic surveillance of circulating MenB strains and assessment of the potential impact of vaccination programs could help inform public health policy. In this study, a collection of 493 strains was analysed, collected in Belgium by the National Reference Centre between 2016 and 2022. Slide agglutination was used for serogroup determination and whole genome sequencing (WGS) was used to further characterize these strains. The observed serogroups were: MenB (n = 281), MenY (n = 95), MenW (n = 83), MenC (n = 30), non-groupable isolates (n = 2), MenE (n = 1) and MenX (n = 1). A higher prevalence of MenY and MenW was observed in older adults. MenB isolates were grouped into 110 sequence types (STs), 89 of which belonged to 16 clonal complexes (CCs). Coverage of the MenB-FHbp vaccine (Trumenba, bivalent rLP2086; Pfizer Inc., New York, NY, USA ipv Philadelphia) was predicted using the Meningococcal Deduced Vaccine Antigen Reactivity (MenDeVAR) index. Of the 281 MenB strains collected between 2016 and 2022, 89.1 % (lower limit – upper limit: 78.6–100.0 %) were predicted by MenDeVAR to be covered by the vaccine. This study highlights the benefits of a pathogen surveillance program and the need for experimental characterization of continuously evolving antigenic variants. •MenB was the leading cause of IMD in individuals under 65 years of age in Belgium from 2016 to 2022.•Increased prevalence of MenY and MenW observed in older adults.•High diversity of MenB isolates circulating in Belgium, with 110 STs detected, including 32 novel STs.•MenDeVAR predicts a coverage of 89.1 % for the MenB-FHbp vaccine (range: 78.6 % - 100.0 %).

Background. In the absence of an efficacious broadly protective vaccine, serogroup B Neisseria meningitidis (MenB) is the leading cause of bacterial meningitis and septicemia in many industrialized countries. An investigational recombinant vaccine that contains 3 central proteins; Neisserial adhesin A (NadA), factor H binding protein (fHBP) and Neisserial heparin binding antigen (NHBA) has been developed. These antigens have been formulated with and without outer membrane vesicles (rMenB+OMV and rMenB, respectively) from the New Zealand epidemic strain (B:4:P1.7–2,4). In this trial, we assessed the immunogenicity of these formulations in infants, who are at greatest risk of contracting MenB disease. Methods. A total of 147 infants from the United Kingdom were enrolled and randomly assigned to receive rMenB or rMenB+OMV at 2, 4, 6, and 12 months of age or a single dose at 12 months of age. Serum samples taken before and after vaccination were assayed in a standardized serum bactericidal antibody assay against 7 MenB strains. Local and systemic reactogenicity were recorded for 7 days after each vaccination. Analysis was according to protocol. Results. After 3 doses, both vaccines were immunogenic against strains expressing homologous or related NadA and fHBP. rMenB+OMV demonstrated greater immunogenicity than did rMenB and was immunogenic against strains expressing homologous PorA. Both vaccines elicited anamnestic responses after the fourth dose. For both vaccines, responses were lower against strains expressing heterologous fHBP variants and after a single dose at 12 months. Conclusions. The rMenB+OMV vaccine has the potential to protect infants from MenB disease, although the breadth of protection afforded to heterologous antigens requires additional investigation.

A novel multicomponent vaccine against meningococcal capsular group B (MenB) disease contains four major components: factor-H-binding protein, neisserial heparin binding antigen, neisserial adhesin A, and outer-membrane vesicles derived from the strain NZ98/254. Because the public health effect of the vaccine, 4CMenB (Novartis Vaccines and Diagnostics, Siena, Italy), is unclear, we assessed the predicted strain coverage in Europe. We assessed invasive MenB strains isolated mainly in the most recent full epidemiological year in England and Wales, France, Germany, Italy, and Norway. Meningococcal antigen typing system (MATS) results were linked to multilocus sequence typing and antigen sequence data. To investigate whether generalisation of coverage applied to the rest of Europe, we also assessed isolates from the Czech Republic and Spain. 1052 strains collected from July, 2007, to June, 2008, were assessed from England and Wales, France, Germany, Italy, and Norway. All MenB strains contained at least one gene encoding a major antigen in the vaccine. MATS predicted that 78% of all MenB strains would be killed by postvaccination sera (95% CI 63–90, range of point estimates 73–87% in individual country panels). Half of all strains and 64% of covered strains could be targeted by bactericidal antibodies against more than one vaccine antigen. Results for the 108 isolates from the Czech Republic and 300 from Spain were consistent with those for the other countries. MATS analysis showed that a multicomponent vaccine could protect against a substantial proportion of invasive MenB strains isolated in Europe. Monitoring of antigen expression, however, will be needed in the future. Novartis Vaccines and Diagnostics.

BackgroundMeningococcal epidemics in Africa are generally caused by capsular group A strains, but W-135 or X strains also cause epidemics in this region. Factor H–binding protein (fHbp) is a novel antigen being investigated for use in group B vaccines. Little is known about fHbp in strains from other capsular groups MethodsWe investigated fHbp in 35 group A, W-135, and X strains from Africa ResultsThe 22 group A isolates, which included each of the sequence types (STs) responsible for epidemics since 1963, and 4 group X and 3 group W-135 isolates from recent epidemics had genes encoding fHbp in antigenic variant group 1. The remaining 6 W-135 isolates had fHbp variant 2. Within each fHbp variant group, there was 92%–100% amino acid identity, and the proteins expressed conserved epitopes recognized by bactericidal monoclonal antibodies. Serum samples obtained from mice vaccinated with native outer membrane vesicle vaccines from mutants engineered to express fHbp variants had broad bactericidal activity against group A, W-135, or X strains ConclusionsDespite extensive natural exposure of the African population, fHbp is conserved among African strains. A native outer membrane vesicle vaccine that expresses fHbp variants can potentially elicit protective antibodies against strains from all capsular groups that cause epidemics in the region

To combat Neisseria meningitidis serogroup A epidemics in the meningitis belt of sub-Saharan Africa, a meningococcal serogroup A conjugate vaccine (MACV) has been progressively rolled out since 2010. We report the first meningitis epidemic in Niger since the nationwide introduction of MACV. We compiled and analysed nationwide case-based meningitis surveillance data in Niger. Cases were confirmed by culture or direct real-time PCR, or both, of cerebrospinal fluid specimens, and whole-genome sequencing was used to characterise isolates. Information on vaccination campaigns was collected by the Niger Ministry of Health and WHO. From Jan 1 to June 30, 2015, 9367 suspected meningitis cases and 549 deaths were reported in Niger. Among 4301 cerebrospinal fluid specimens tested, 1603 (37·3%) were positive for a bacterial pathogen, including 1147 (71·5%) that were positive for N meningitidis serogroup C (NmC). Whole-genome sequencing of 77 NmC isolates revealed the strain to be ST-10217. Although vaccination campaigns were limited in scope because of a global vaccine shortage, 1·4 million people were vaccinated from March to June, 2015. This epidemic represents the largest global NmC outbreak so far and shows the continued threat of N meningitidis in sub-Saharan Africa. The risk of further regional expansion of this novel clone highlights the need for continued strengthening of case-based surveillance. The availability of an affordable, multivalent conjugate vaccine may be important in future epidemic response. MenAfriNet consortium, a partnership between the US Centers for Disease Control and Prevention, WHO, and Agence de Médecine Preventive, through a grant from the Bill & Melinda Gates Foundation.

A multicomponent meningococcal serogroups ABCWY vaccine (MenABCWY) could provide broad protection against disease-causing meningococcal strains and simplify the immunisation schedule. The aim of this trial was to confirm the effect of the licensed meningococcal serogroup B (MenB) vaccine, 4CMenB, against diverse MenB strains, and to assess the breadth of immune response against a panel of 110 MenB strains for MenABCWY containing the antigenic components of 4CMenB and licensed serogroups ACWY vaccine, MenACWY-CRM, the non-inferiority of the immune response with MenABCWY versus 4CMenB and MenACWY-CRM, safety, and MenABCWY lot-to-lot consistency. We conducted a phase 3 randomised, controlled, observer-blinded trial of healthy adolescents and young adults (age 10–25 years) across 114 centres in Australia, Canada, Czechia, Estonia, Finland, Türkiye, and the USA. Exclusion criteria included previous vaccination with a MenB vaccine or (within the last 4 years) MenACWY vaccine. Participants were randomly allocated (5:5:3:3:3:1 ratio) via a central randomisation system using a minimisation procedure to receive 4CMenB at months 0, 2, and 6 (referred to as 4CMenB 0–2–6 hereafter); or 4CMenB at months 0 and 6 (referred to as 4CMenB 0–6 hereafter); or MenABCWY (three groups, each receiving one production lot of the MenACWY-CRM component) at months 0 and 6; or MenACWY-CRM at month 0. Demonstration in the per-protocol set of the consistency of three MenACWY-CRM component lots of the MenABCWY vaccine was a primary objective (demonstrated with two-sided 95% CIs for the ratio of human serum bactericidal antibody [hSBA] geometric mean titres against each serogroup within predefined criteria [0·5–2·0]). The primary endpoints (breadth of immune response) for the MenB component of MenABCWY and 4CMenB were measured using the endogenous complement hSBA (enc-hSBA) assay against a panel of 110 diverse MenB invasive disease strains. For each serum sample, 35 strains from the 110 MenB strain panel were randomly selected for testing. The 4CMenB breadth of immune response data have been published separately. For MenABCWY, breadth of immune response was assessed in two analyses: a test-based analysis of the percentage of samples (tests) without bactericidal serum activity against MenB strains 1 month after two MenABCWY doses versus the percentage after one MenACWY-CRM dose in the per-protocol set, and a responder-based analysis of the percentage of participants (responders) whose sera killed 70% or more strains at 1 month after two MenABCWY doses in the full analysis set. A lower limit of two-sided 95% CI above 65% would demonstrate breadth of immune response. Other primary outcomes included non-inferiority (5% margin) of two MenABCWY doses versus two 4CMenB doses by enc-hSBA assay in the per-protocol set, non-inferiority (10% margin) of two MenABCWY doses versus one MenACWY-CRM dose in MenACWY vaccine-naive participants by traditional hSBA assay in the per-protocol set, and safety in all vaccinated participants. This trial is registered with ClinicalTrials.gov, NCT04502693, and is complete. Between Aug 14, 2020, and Sept 3, 2021, 3651 participants were enrolled and randomly allocated (900 in the 4CMenB 0–2–6 group and 908 in the 4CMenB 0–6 group, 1666 in the three MenABCWY groups combined, and 177 in the MenACWY-CRM group). All primary objectives for MenABCWY were met. Consistency of immune responses against the three production lots of the MenACWY component of MenABCWY was demonstrated since two-sided 95% CIs for the ratios of hSBA geometric mean titres against serogroups A, C, W, and Y for each pair of lots were within the predefined equivalence criteria. The lot data were pooled for the remainder of MenABCWY endpoints. By enc-hSBA assay, breadth of immune response against the MenB strain panel was 77·9% (95% CI 76·6 to 79·2) in the test-based analysis and 84·1% (81·4 to 86·5; 687 of 817 participants) in the responder-based analysis. Non-inferiority of MenABCWY to 4CMenB was demonstrated by enc-hSBA assay: the difference in percentage of samples with bactericidal serum activity between the MenABCWY group (82·5% [95% CI 82·1 to 83·0]; 21 222 of 25 715) and 4CMenB 0–2 group (83·1% [82·7 to 83·6]; 22 921 of 27 569) was –0·61% (–1·25 to 0·03). Non-inferiority of two-dose MenABCWY to one-dose MenACWY-CRM was demonstrated by traditional hSBA assay, with differences between the MenABCWY group and MenACWY group in percentages of participants with a four-fold rise in hSBA titres of 11·3% (5·9 to 19·0) for serogroup A, 47·2% (38·1 to 56·3) for serogroup C, 35·3% (26·9 to 44·5) for serogroup W, and 27·0% (19·4 to 35·8) for serogroup Y. MenABCWY reactogenicity was mostly of mild or moderate severity and transient, with similar frequencies of adverse events in the MenABCWY and 4CMenB groups and no safety concerns were identified. This study demonstrates breadth of immune response against a panel of 110 MenB strains for the MenB component of the investigational MenABCWY vaccine, when administered as a 0–6 months schedule to the target population of adolescents and young adults, with predefined criteria for success met for both breadth of immune response endpoints and for non-inferiority versus 4CMenB. This investigational vaccine could provide broad meningococcal serogroup coverage in a simplified immunisation schedule, thus aiding the public health attempt in preventing invasive meningococcal disease due to five Neisseria meningitidis serogroups in adolescents and young adults. GSK.

Bivalent rLP2086 is a recombinant factor H binding protein-based vaccine approved in the USA for prevention of meningococcal serogroup B disease in 10–25-year-olds. We aimed to assess the persistence of bactericidal antibodies up to 4 years after a three-dose schedule of bivalent rLP2086. We did this randomised, single-blind, placebo-controlled, phase 2 trial at 25 sites in Australia, Poland, and Spain. In stage 1 of the study (February, 2009–May, 2010), healthy adolescents (aged 11–18 years) were randomly assigned, via an interactive voice and web-response system with computer-generated sequential random numbers, to receive either ascending doses of vaccine (60 μg, 120 μg, and 200 μg) or placebo at months 0, 2, and 6. Dispensing staff were not masked to group allocation, but allocation was concealed from principal investigators, participants and their guardians, and laboratory personnel. In stage 2 of the study (reported here), we enrolled healthy adolescents who had received three doses of 120 μg bivalent rLP2086 (the optimum dose level identified in stage 1) or saline. Immunogenicity was determined in serum bactericidal antibody assay using human complement (hSBA) by use of four meningococcal serogroup B test strains expressing vaccine-heterologous factor H binding protein variants: PMB80 (A22), PMB2001 (A56), PMB2948 (B24), and PMB2707 (B44). Immunogenicity in stage 2 was assessed at months 6, 12, 24, and 48 post-vaccination. We did analysis by intention to treat. This trial is registered as ClinicalTrials.gov number NCT00808028. Between March 17, 2010, and Feb 8, 2011, 170 participants who received 120 μg of bivalent rLP2086 and 80 participants who received placebo in stage 1 of the study were entered into stage 2; 210 participants completed stage 2 up to 48 months. 1 month after the third vaccination, 93% (n=139/149) to 100% (n=48/48) of vaccine recipients achieved protective hSBA titres equal to or greater than the lower limit of quantification to each test strain, compared with 0% (n=0/25) to 35% (n=8/23) of control recipients. Despite initial declines in seroprotective hSBA titres for all four test strains, for three test strains (A22, A56, and B24), more than 50% of bivalent rLP2086 recipients continued to achieve titres equal to or greater than the lower limit of quantification at months 6 (57% [n=93/163] to 89% [n=42/47]), 12 (54% [n=84/155] to 69% [n=33/48]), 24 (53% [n=26/49] to 54% [n=82/152]), and 48 (51% [n=24/47] to 59% [n=79/134]); corresponding values in the control group were 14% (n=11/80) to 22% (n=5/23) at month 6, 13% (n=10/78) to 29% (n=22/76) at month 12, 16% (n=12/74) to 36% (n=8/22) at month 24, and 24% (n=16/68) to 35% (n=8/23) at month 48. For test strain B44, hSBA titres equal to or greater than the lower limit of quantification were shown in 37% (n=18/49) of vaccine recipients at 6 months, in 29% (n=14/48) at 12 months, in 22% (n=11/49) at 24 months, and in 20% (n=10/49) at 48 months, compared with 0% (n=0/25) of control recipients at month 6, 4% (n=1/25) at months 12 and 24, and 12% (n=3/25) at month 48. Adverse events were reported in seven (4%) of 170 participants in the bivalent rLP2086 group and two (3%) of 80 participants in the control group; no event was deemed related to vaccine. After three doses of bivalent rLP2086, protective hSBA titres above the correlate of protection (≥1/4) were elicited up to 4 years in more than 50% of participants for three of four meningococcal serogroup B test strains representative of disease-causing meningococci expressing vaccine-heterologous antigens. Further studies will be needed to assess possible herd immunity effects with meningococcal serogroup B vaccines and the need for a booster dose to sustain individual protection against invasive meningococcal disease. Pfizer.