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•Most cases of invasive meningococcal disease in Europe are caused by serogroup B.•The notification rate of serogroup B is highest among infants.•Routine MCC vaccination was the driving force behind the decreasing trend in SgC.•The notification rates of serogroups Y and W are increasing in some countries. Invasive meningococcal disease (IMD) is a major cause of bacterial meningitis and septicaemia although infection by some serogroups may be prevented through vaccination. We aimed to describe the epidemiology of IMD in EU/EEA countries during 2004–2014 to monitor serogroup- and age-specific trends, and compare country trends by the period of meningococcal C conjugate (MCC) vaccine introduction. We analysed IMD surveillance data by age, gender, serogroup, country and outcome. We estimated the percentage change in annual notification rate (NR), using linear regression analysis of the log of the annual NR. We grouped countries by the year they introduced MCC vaccination into their routine immunisation programmes. The overall NR was 0.9/100 000 population, and decreased 6.6% (95%CI: −8.0%;−5.1%) annually. Infants had the highest NR (16.0/100 000), and there were decreasing trends in all age groups <50years. Serogroup B (SgB) caused 74% of all cases, and the majority of cases in all age groups. There were decreasing trends in SgB and serogroup C (SgC) and an increasing trend in serogroup Y. Countries that introduced MCC vaccination before, and between 2004 and 2014, had decreasing trends in NR of SgC, but not countries without routine MCC vaccination. Our findings support evidence that routine MCC vaccination was the driving force behind the decreasing SgC trend. Vaccinating against SgB in the first year of life could help reduce the burden of IMD due to this serogroup. Changing serogroup-specific NR trends highlight the need for high-quality surveillance data to accurately assess the changing epidemiology of IMD, the effectiveness and impact of implemented vaccines, and the need for future vaccines.

Serogroup causing invasive meningococcal disease (IMD) can change abruptly, as it occurred in Chile when serogroup predominance switched from MenB to MenW in 2012. As a response, a national vaccination strategy was implemented since 2012 using tetravalent meningococcal-conjugate vaccines (MCV–ACWY) in children 9 months through 4 years of age. The aim of this study was to describe IMD cases by MenW in Chile 2009–2016, and to analyse its trend after the introduction of MCV-ACWY. Descriptive study of IMD cases in Chile, period 2009–2016. Cumulative incidence and mortality rate per 100,000 inhabitants, and case fatality rate (CRF) were used for descriptive analysis. Linear regression was used for post-intervention trend analysis. In 2012, MenW, mainly ST-11 cc, became predominant. MenW incidence rose from 0.01/100,000 inhabitants in 2009 to a maximum of 0.6/100,000 in 2015. Infants and adults 80 years of age and older were mostly affected, with an incidence peak of 9.7/100,000 and 1.6/100,000, respectively, in 2015. In the group of children from 1 to 4 years of age MenW incidence declined from 1.3/100,000 in 2012 to 0.1/100,000 in 2016, a 92.3% reduction after vaccination implementation. In the same period and age-cohort, CFR decreased from 23% to 0%. High mortality rates concentrated in infants and adults 80 years of age and over. MenW became predominant in Chile since 2012. IMD cases increased steadily from 2009 to 2016, with higher incidence, CFR and mortality concentrating in infants and people 80 years of age and older. MCV–ACWY provided direct protection against MenW, reducing its incidence after mass meningococcal vaccine implementation. Indirect effects of vaccination are not yet observed.

We report a cluster of serogroup B invasive meningococcal disease identified via genomic surveillance in older adults in England and describe the public health responses. Genomic surveillance is critical for supporting public health investigations and detecting the growing threat of serogroup B Neisseria meningitidis infections in older adults.

Three mother-baby pairs with invasive meningococcal disease occurred over 7 months in Western Australia, Australia, at a time when serogroup W sequence type 11 clonal complex was the predominant local strain. One mother and 2 neonates died, highlighting the role of this strain as a cause of obstetric and early neonatal death.

•The first culture-confirmed pediatric IMD case caused by Y:cc23 in China.•The increase of NmY isolates warranting the wider usage of MPC-ACYW vaccine in China.•The Chinese cc23 isolates with phenotypically resistance to penicillin or quinolones.•Identification of the global dissemination of the three cc23 sub-lineage. Serogroup Y Neisseria meningitidis (NmY) is rare in China, and only serogroup A and C meningococcal polysaccharide vaccines (MPVs) are included in the national vaccination schedule. We describe a case of fulminant meningococcemia caused by NmY, which occurred in a pediatric patient (2 years old) for the first time in China, confirmed by culture. Although the boy was treated in time, the dry gangrene in his toes and fingers left him with severe sequelae. An NmY isolate was cultured from the blood of the patient, and showed decreased susceptibility to penicillin (minimum inhibitory concentration of 0.125 μg/ml), with sequence type (ST) 1655 assigned to clonal complex (cc) 23. Genomic analysis showed it was clustered with isolates from Italy, UK, Finland, and South Africa, sharing designation of Y:P1.5–1,10–1:F4-1:ST-1655(cc23). The emergence of NmY invasive meningococcal disease cases challenges local immunization strategy and warrants wider usage of MPV-ACYW if there is sustained circulation of NmY.

Neisseria meningitidis, a bacterium that colonizes in the human nasopharynx, occasionally causes invasive meningococcal disease leading to meningitis or septicemia. Different serogroups and lineages (clonal complexes) are related to the occurrence and epidemiology of N. meningitidis. Despite vaccines for most serogroups, N. meningitidis lineages causing unusual clinical manifestations and a higher fatality rate compared to other lineages have been reported in South America. The present study focused on exploring the diversity of N. meningitidis prophages from South America and their relationship with the epidemiological variables of these strains. We found a high diversity of prophages among the different clonal complexes. By comparing them with previously described N. meningitidis phages and prophages, we revealed groups of prophages sharing similar compositions, which could be useful for prophage comparison in N. meningitidis. Furthermore, we observed a high correlation between the prophage content and epidemiological features, e.g., pathogenicity or clonal complex. Additionally, a distinctive filamentous prophage named here as IMSAR-11 (Invasive Meningococci from South America Related to cc11) was identified. Interestingly, two versions of IMSAR-11, circular and chromosomally integrated, were found. Overall, this study reinforces the importance of the genomic characterization of circulating N. meningitidis lineages to generate new targets for lineage monitoring, diagnosis, or appropriateness of vaccine development. Further studies are necessary to understand the role of these prophages in the persistence, dispersal, and virulence of N. meningitidis in the world.

•MenB is now the predominant serogroup among pediatric IMD cases in Turkey.•Invasive MenB in Turkey is diverse and includes several clonal complexes.•MenW IMD persists in Turkey and includes several clonal complexes.•Predicted MenB strain coverage by MenB vaccines in Turkey is high but requires ongoing monitoring. Diverse Neisseria meningitidis strains belonging to various serogroups and clonal complexes cause epidemic and endemic life-threatening disease worldwide. This study aimed to investigate the genetic diversity of recent invasive meningococci in Turkey with respect to multilocus sequence type (MLST) and also meningococcal serogroup B (MenB) vaccine antigens to enable assessment of potential MenB strain coverage using the genetic Meningococcal Antigen Typing System (gMATS). Fifty-four isolates, representing 37.5% of all pediatric (ages 0–18 years) invasive meningococcal disease cases in Turkey from January 2013 to December 2017, underwent genome sequence analysis. Thirty-six (66.7%) isolates were MenB, 10 (18.5%) were serogroup W (MenW), 4 (7.4%) were serogroup A (MenA), 3 (5.6%) were serogroup Y (MenY) and 1 (1.8%) was serogroup X (MenX). The MenB isolates were diverse with cc35 (19.4%), cc41/44 (19.4%) and cc32 (13.8%) as the most prevalent clonal complexes. The MenW isolates (n = 10) comprised cc11 (n = 5), ST-2754 (cc-unassigned; n = 4) and cc22 (n = 1). gMATS was indicative of high 4CMenB coverage (72.2–79.1%) of Turkish invasive MenB strains from pediatric patients. Strain coverage of several clonal complexes differed from that seen elsewhere in Europe highlighting the importance of performing local assessments and also the use of phenotypic methods, i.e. MATS, where possible. All of the isolates possessed in-frame fhbp alleles and so were potentially covered by MenB-fHbp. Continued surveillance is essential to guide recommendations for current and future vaccines as well as understanding changes in epidemiology.

The present study describes the epidemiology of invasive meningococcal disease (IMD) in Greece for the period 2006–2016. Combined data from notified and laboratory-confirmed IMD cases were obtained from the two involved National Centres (Epidemiology and Reference Laboratory). Laboratory identification and typing was carried out by both conventional (culture) and molecular methods (PCR, MLST, PorA, and FetA typing). A total of 796 IMD cases were notified; of those, 720 (91%) were laboratory confirmed. Overall, a decline on the annual incidence of confirmed cases was observed, ranging from 0.91 (2006) to 0.47 (2016) /100,000. A similar trend was observed in most age groups especially in children 0–4 years (7.7 to 2.9/100,000), with the exception of an increase in the incidence rate in adults > 20 years (0.21 to 0.32/100,000). The overall case fatality rate was 6.5% (52/796), annual range 2–13%. Among 658 strains which were typed by sero/genogroup, 80% were identified as MenB (annual range 65–92%); however, a decline was observed in MenB incidence from 5.3 (2006) to 2.7 (2016), among infants and toddlers, while MenW (1%), MenY (2%), and MenA (1%) remained low. During the 11 years, the annual incidence of IMD declined by 50%, especially in the 0–4-year age group, due mainly to MenB. Continuous surveillance of IMD is important for the development of future vaccination and public health policies.

The epidemiology of invasive meningococcal disease (IMD) is unpredictable, varies by region and age group and continuously evolves. This review aimed to describe trends in the incidence of IMD and serogroup distribution by age group and global region over time. Data were extracted from 90 subnational, national and multinational grey literature surveillance reports and 22 published articles related to the burden of IMD from 2010 to 2019 in 77 countries. The global incidence of IMD was generally low, with substantial variability between regions in circulating disease-causing serogroups. The highest incidence was usually observed in infants, generally followed by young children and adolescents/young adults, as well as older adults in some countries. Globally, serogroup B was a predominant cause of IMD in most countries. Additionally, there was a notable increase in the number of IMD cases caused by serogroups W and Y from 2010 to 2019 in several regions, highlighting the unpredictable and dynamic nature of the disease. Overall, serogroups A, B, C, W and Y were responsible for the vast majority of IMD cases, despite the availability of vaccines to prevent disease due to these serogroups.