Epidemiology Of Meningococcal Disease Research Articles

Use of a meningococcal group B vaccine (4CMenB) in populations at high risk of gonorrhoea in the UK.

The meningococcal group B vaccine, 4CMenB, is a broad-spectrum, recombinant protein vaccine that is licensed for protection against meningococcal group B disease in children and adults. Over the past decade, several observational studies supported by laboratory studies have reported protection by 4CMenB against gonorrhoea, a sexually transmitted infection caused by Neisseria gonorrhoeae. Gonorrhoea is a major global public health problem, with rising numbers of diagnoses and increasing resistance to multiple antibiotics. In England, more than 82 000 cases of gonorrhoea were diagnosed in 2022, with nearly half of the cases diagnosed among gay, bisexual, and other men who have sex with men. There are currently no licensed vaccines against gonorrhoea but 4CMenB is estimated to provide 33-47% protection against gonorrhoea. On Nov 10, 2023, the UK Joint Scientific Committee on Vaccination and Immunisation agreed that a targeted programme should be initiated using 4CMenB to prevent gonorrhoea among individuals at higher risk of infection attending sexual health services in the UK. This decision was made after reviewing evidence from retrospective and prospective observational studies, laboratory and clinical data, national surveillance reports, and health economic analyses. In this Review, we summarise the epidemiology of invasive meningococcal disease and gonorrhoea in England, the evidence supporting the use of 4CMenB for protection against gonorrhoea, and the data needed to inform long-term programme planning and extension to the wider population.

4CMenB Vaccination to Prevent Meningococcal B Disease in Vietnam: Expert Review and Opinion.

An advisory board meeting was held with experts in Vietnam (Hanoi, August 2022), to review the evidence on invasive meningococcal disease (IMD) epidemiology, clinical management, and meningococcal vaccines to reach a consensus on recommendations for meningococcal vaccination in Vietnam. IMD is a severe disease, with the highest burden in infants and children. IMD presents as meningitis and/or meningococcemia and can progress extremely rapidly. Almost 90% of deaths in children occur within the first 24h, and disabling sequelae (e.g., limb amputations and neurological damage) occur in up to 20% of survivors. IMD patients are often hospitalized late, due to mild and nonspecific early symptoms and misdiagnosis. Difficulties related to diagnosis and antibiotic misuse mean that the number of reported IMD cases in Vietnam is likely to be underestimated. Serogroup B IMD is predominant in many regions of the world, including Vietnam, where 82% of IMD cases were due to serogroup B (surveillance data from 2012 to 2021). Four component meningococcal B vaccine (4CMenB) is used in many countries (and is part of the pediatric National Immunization Program in 13 countries), with infant vaccination starting from two months of age, and a 2 + 1 dosing schedule. Experts recommend 4CMenB vaccination as soon as possible in Vietnam, starting from two months of age, with a 2 + 1 dosing schedule, and at least completing one dose before 6 months of age.

Epidemiology of Meningococcal Disease in Four South American Countries and Rationale of Vaccination in Adolescents from the Region: Position Paper of the Latin American Society of Pediatric Infectious Diseases (SLIPE).

Descriptive study of MD incidence rates, serogroup distribution, case fatality rates (CFR), and MCV uptakes during the period 2010-2021 in Argentina, Brazil, Chile, and Uruguay. Data were extracted from national surveillance programs, reference laboratories, NIPs, and Pubmed. MD overall incidence from 2010 to 2021 have a decreasing trend in Argentina (0.37 [IQR = 0.20-0.61]), Brazil (0.59 [IQR = 0.54-1.22]), and Chile (0.45 [IQR = 0.40-0.77]), while a significant increase in Uruguay (0.47 [IQR = 0.33-0.69]) was found from 2016 to 2019. During the COVID-19 pandemic, all countries sharply reduced their MD incidence. The highest incidence rates were observed among infants, followed by children 1-4 years of age. No second peak was evident in adolescents. A reduction in serogroup C, W, and Y cases has occurred in Argentina, Brazil, and Chile after introduction of MCV, serogroup B becoming predominant in all four countries. Median CFR was 9.0%, 21%, 19.9%, and 17.9% in Argentina, Brazil, Chile, and Uruguay, respectively. Median uptake of MCV for Argentina and Brazil were 66.6% and 91.0% for priming in infants; 54.7% and 84.5% for booster in toddlers; and 47.5% and 53% for adolescents; while for Chile, 95.6% for toddlers. Experience after the implementation of MCV programs in South America was successful, reducing the burden of MD due to the vaccine serogroups. High vaccine uptake and the inclusion of adolescents will be crucial in the post-pandemic period to maintain the protection of the population. The increase in the proportion of serogroup B cases emphasizes the importance of continuous surveillance to guide future vaccination strategies.

Molecular characteristics of Neisseria meningitidis carriage strains in university students in Lithuania

BackgroundNeisseria meningitidis can be carried asymptomatically in the human oropharynx without causing symptoms. Meningococcal carriage is relevant to the epidemiology of invasive meningococcal disease (IMD). No carriage studies have been performed among the general population in Lithuania, whereas the incidence of IMD in Lithuania was among the highest in European countries from 2009 to 2019.ResultsWe analyzed a total of 401 oropharyngeal samples collected from university students from December 2021 to February 2023 for N. meningitidis carriage using direct swab PCR assays and culture. The overall carriage prevalence based on both or either swab PCR or culture was 4.99%. PCR-based assays were used to characterize 15 carriage isolates, including detection of genogroup, multilocus sequence typing profile, and typing of antigens PorA and FetA. The most common carriage isolates were capsule null locus (cnl), accounting for 46.7%, followed by genogroups B (26.7%) and Y (13.3%). We also performed a molecular characterization of invasive N. meningitidis isolates collected during the COVID-19 pandemic and post-pandemic period to understand better the meningococcal carriage in the context of prevailing invasive strains. Despite the substantial decrease in the incidence of IMD during the 2020–2022 period, clonal complex 32 (CC32) of serogroup B continued to be the most prevalent IMD-causing CC in Lithuania. However, CC32 was not detected among carriage isolates. The most common CCs were CC269, CC198, and CC1136. The antigen peptide variants found in most carried isolates were classified as ‘insufficient data’ according to the MenDeVAR Index to evaluate the potential coverage by the 4CMenB vaccine. Nearly half of the isolates were potentially covered by the Men-Fhbp vaccine. Resistance to ciprofloxacin was detected only for one cnl isolate. All isolates were susceptible to penicillin and ceftriaxone. Our analysis identified frequent partying (≥ 4 times/month) as a risk factor for meningococcal carriage, whereas smoking, living in a dormitory, and previous COVID-19 illness were not associated with the carriage.ConclusionsOur study revealed a low prevalence of meningococcal carriage among university students in Lithuania. The carriage isolates showed genetic diversity, although almost half of them were identified as having a null capsule locus.

Epidemiological and strain characteristics of invasive meningococcal disease prior to, during and after COVID-19 pandemic restrictions in England

In 2020, COVID-19 pandemic restrictions led to a major suppression of meningococcal disease in England. Here we describe the epidemiology of invasive meningococcal disease in the three years prior to the COVID-19 pandemic, and the three years immediately after the introduction of restrictions. The UK Health Security Agency conducts national meningococcal disease surveillance in England consisting of laboratory-based case confirmation with strain characterisation by culture and/or molecular detection, as well as clinical follow-up of all cases. In the pre-pandemic period, 554-742 IMD cases were laboratory-confirmed per year. MenB caused 57.2% of cases, followed by MenW (22.7%), MenY (10.6%) and MenC (7.7%). The introduction of restrictions in late March 2020 led to a 73% reduction in IMD. After the removal of restrictions in 2021, a resurgence in MenB was observed, primarily in teenagers and young adults. During the following winter period (2022/23), MenB disease increased to the highest level since 2012 with cases rising across multiple age groups, however, cases in young children eligible for MenB vaccination remained lower than prior to the pandemic. MenACWY cases remained very low throughout the pandemic period. Once pandemic restrictions in England were removed, MenB quickly rebounded- initially driven by a resurgence in teenagers/young adults, but later among other age groups. MenACWY cases remain very low due to the protection afforded by the adolescent MenACWY conjugate vaccine programme.

A National Advisory Committee on Immunization (NACI) update on invasive meningococcal disease (IMD) epidemiology and program-relevant considerations for preventing IMD in individuals at high risk of exposure.

Following recent outbreaks of invasive meningococcal disease (IMD) in Canada and updates to provincial vaccination guidelines, the National Advisory Committee on Immunization (NACI) conducted a targeted review of evidence with a focus on immunization of adolescents and young adults. NACI reviewed national and international immunization recommendations for populations at high-risk of IMD, national IMD epidemiology and program-relevant considerations. Given the varied IMD epidemiology, NACI determined that recommending a pan-Canadian targeted program is currently challenging and that regional programs may be better suited to prevent IMD in population groups considered to be at high-risk of exposure. Further data is needed to ascertain contemporary risk factors for IMD (including activities and settings associated with bacterial acquisition, carriage and transmission) and estimate the true cost of meningococcal vaccine-preventable infections in Canada. To support provinces and territories in their decision-making, an outline of program-relevant elements for provincial and territorial consideration is provided.

Epidemiology of invasive meningococcal disease and its sequelae: a population-based study in Italian primary care, 2000-2019.

Invasive meningococcal disease (IMD) is a severe infectious disease. Although effective preventive and therapeutical strategies are available, the fatality rate remains high in the general population, with an occurrence of meningococcal-related severe sequelae involving 10-20% of survivors. Given the crucial role of general practitioners in recognizing and preventing IMD and its related sequelae, we aim to assess the burden of these conditions in primary care. Using an Italian primary care database, the incidence rate of IMD was calculated in the period 2000-2019 by capturing the first diagnosis registered during follow-up. As far as meningococcal-related sequelae are concerned, we identified and clinically evaluated each potential sequela during the first 3 months, from 3 to 12 months, and up to 36 months. Among 508 patients diagnosed with IMD, 403 (incidence rate: 0.24 per 10,000 person-years) comprised those diagnosed with IMD in patients aged 15 years or older. We ascertained 104 sequelae (20.4%); 76% of them occurred in those aged 25 or older; 42, 27, and 35 were assessed as short-, medium-, or long-term sequelae, respectively. Overall, 4.7% of IMD patients reported physical sequelae, while 12.2% and 5.7% of patients reported neurological and psychological sequelae, respectively. Our study showed that a substantial proportion of IMD and related sequelae occur in individuals aged over 25, with a non-negligible burden for healthcare systems. As for the paediatric population, effective communication on the relevance of meningococcal vaccination in adults should be proficiently fostered.

Invasive meningococcal disease in Norway in the two decades before the COVID-19 pandemic

ObjectivesDisease caused by the bacterium Neisseria meningitidis remains a worldwide public health challenge, despite the steadily decreasing incidence in Western countries. The objective of this study was to explore the epidemiology of invasive meningococcal disease in Norway over the last two decades. DesignAll isolates sent to the National Reference Laboratory from patients with invasive meningococcal disease between the years 2000 and 2019 were analyzed using whole genome sequencing (total: 625). ResultsA five-fold decrease in case numbers occurred over this period, and the situation has gone from being dominated by serogroup B to one where serogroups Y and W are more prevalent. Concurrently, the mean age at infection has increased from 18 to 33 years. Among the 350 serogroup B isolates, 87% were an exact match or cross-reactive with one or both the currently available serogroup B vaccines, but the proportion decreased in the past decade. Core genome analyses revealed a high variation in the number of allelic differences accumulated in epidemiologically linked isolates to the point that near-identical isolates were found several years apart. ConclusionAllelic distance is an imprecise metric for the degree of epidemiologic linkage between isolates in N. meningitidis.

Epidemiology and Clinical Burden of Meningococcal Disease in France: Scoping Review.

Invasive meningococcal disease (IMD) remains a significant health concern due to its unpredictable nature and its rapid progression. Even if occurrence of IMD is strictly monitored by a national surveillance network, no information on long-term sequelae is reported, making it difficult to assess the entire clinical burden of IMD in France. The aim of this scoping review was to analyze the epidemiology and the clinical burden of IMD in France by reporting the main epidemiological parameters, and by describing the clinical consequences and the care pathway of patients. The process of the review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension to the Scoping Reviews guidelines. In France, the incidence of IMD cases has been fluctuating over time, characterized by an overall downward trend linked to a decrease in Sg B cases and the introduction of mandatory vaccination against Sg C. Sg W cases increased in recent years (from 5% to 21% in 2019). The case fatality rate remained constant (6-12.9%). The most frequently reported sequelae were severe neurological disorder, epilepsy, and anxiety. However, data on sequelae and care pathways were scarce. Further research should concentrate on providing robust identification of sequelae and the subsequent impact on quality of life, as well as on the organization of optimal care and support for patients and their families.

Epidemiology of invasive meningococcal disease worldwide from 2010-2019: a literature review.

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.

57 Update of IMPACT Invasive Meningococcal Surveillance, 2016-2020

Abstract Background Meningococcal conjugate vaccine (MCV) programs in Canada began in 2002. Objectives This study examines the most recent surveillance data to describe the current Canadian epidemiology of invasive meningococcal disease (IMD) and the effect of MCV programs, especially on age and serogroup distribution. Design/Methods Active metropolitan area surveillance for hospitalization of adults and children due to IMD, which was defined as a clinical infection with Neisseria meningitidis isolated or detected by molecular methods or culture from a sterile body site. The study was conducted via the 12 centres of the Canadian Immunization Monitoring Program, Active (IMPACT) network from January 1, 2016 – December 31, 2020. Results During 2016-2020, a total of 105 pediatric (<20 years of age) and 145 adult IMD cases occurred. Serogroup B accounted for the greatest proportion of pediatric cases (N=58, 55.2%), followed by W (n=19, 18.1%) and Y (n=9, 8.6%) and C (n=2, 1.9%). Among adults, serogroup W accounted for the majority of cases (n=55, 38.0%), followed by Y (n=41, 28.3%), B (n=33, 22.8%) and C (n=7, 4.8%). The age distribution for serogroups covered by MCV programs has shifted to adults. The median age was 24.2 years (33.4 mean). Whereas the median age of serogroup B cases was 7.7 years (19.4 years mean) with 63.7% of cases occurring in children < 19 years of age and 46.2% in children 0-4 years of age. A total of 20 people died from meningococcal infections in 2016–2020. Five deaths were in children, four from serogroup B and one from serogroup W. Fifteen deaths were in adults, one from serogroup B, eight from serogroup W, three from serogroup Y, and three from Non-typeable/Other/Unknown serogroups. Conclusion Serogroup B, which is not covered by MCV programs, still accounts for the majority of pediatric IMD. Serogroup C has been controlled and rarely causes pediatric infection. With the implementation of MCV programs in children and adolescents, the median and mean age at infection has increased across all serogroups, except serogroup B. Serogroup W is still causing IMD among pediatric age groups.

Meningococcal Disease and Carriage in the Philippines: A Review of Recent Data

This article reviews recent data on meningococcal disease and carriage in the Philippines. It aims to provide information on the epidemiology of meningococcal disease, its carriage, data on prevention, and the impact of vaccination on disease and carriage. The World Health Organization considers the Philippines as having low endemicity for meningococcal disease. However, current data underestimates the true burden in the country due to many factors. In recent years, data from the Philippines show a high case-fatality rate since only the septicemic form is being reported. Studies on asymptomatic meningococcal carriage rates are sparse, with one study by Gonzales, et al. investigating the prevalence of meningococcal nasopharyngeal carriage in Filipinos aged 5-24 years old living in an urban setting. The study showed that the overall prevalence of carriage was 3.7% and was highest (9%) among the 10-14 age group. Serogroup B was the most common isolate. Effective meningococcal vaccines are available. Although not included in the National Immunization Program, medical societies recommend giving vaccines to individuals at high risk of infection. Data on local epidemiology accounting for the disease and asymptomatic carriage are important to strengthen future programs on immunization and prevention of meningococcal disease.

Epidemiology of invasive meningococcal disease in Canada, 2012–2019

Epidemiology of invasive meningococcal disease in Canada, 2012–2019

Epidemiology of invasive meningococcal disease in Canada, 2012-2019.

A variety of routine childhood and adolescent meningococcal vaccination programs using monovalent (serogroup C) and quadrivalent (A, C, Y, W) conjugate vaccines have been implemented in Canada since 2002, resulting in a decrease in invasive meningococcal disease (IMD) incidence, particularly in serogroup C. Meningococcal vaccines have also been used for outbreak response, including the multicomponent vaccine serogroup B vaccine. This report describes the epidemiology of IMD in Canada from 2012 to 2019. Case data were obtained from the National Enhanced IMD Surveillance System between January 1, 2012 and December 31, 2019. Isolates were sent to the National Microbiology Laboratory for confirmation of serogroup and further studies including phenotype and clonal complex identification. A total of 983 cases of IMD were reported between 2012 and 2019. Overall, the age-adjusted incidence of IMD from 2012 to 2019 was 0.34 cases per 100,000 population per year when standardized to the Canadian 2011 population age distribution (95% CI: 0.32-0.36). Infants younger than one year of age had the highest average age-specific incidence rate (3.6 cases per 100,000 population per year, 95% CI: 2.8-4.3). The highest age-adjusted incidence rate was associated with serogroup B (0.17 cases per 100, 000 population per year, 95% CI: 0.16-0.19). Prior to 2015, most invasive serogroup W isolates were identified as clonal complex 22 (ST-22 CC) and the increase in serogroup W in Canada in recent years has been associated with the replacement of the endemic ST-22 CC with the hyper-virulent ST-11 CC. Invasive meningococcal disease is a rare but severe infection in Canada that mostly affects the very young. Serogroup B continues to account for the greatest proportion of disease. Serogroup W associated with ST-11 CC is becoming a growing contributor of disease in all age groups not protected by serogroup W-containing vaccines.

Epidemiology of invasive meningococcal disease and sequelae in the United Kingdom during the period 2008 to 2017 \u2013 a secondary database analysis

BackgroundInvasive meningococcal disease (IMD) causes high fatality in untreated patients alongside long-term sequelae in 20% survivors. For a comprehensive assessment of epidemiology, an analysis of these sequelae is required. This study aims to investigate the epidemiology of disease between 2008 and 2017 including a description of the sequelae, through the analysis of data collected from the UK Clinical Practice Research Datalink (CPRD) linked with data from the Hospital Episode Statistics (HES), and Office for National Statistics (ONS) mortality registry data.MethodsThis was a 10-year retrospective observational cohort study designed to describe the incidence, case-fatality rate (CFR) and occurrence of sequelae due to meningococcal disease, in the UK between 2007 and 2017 using data from the UK CPRD-HES-ONS. Cases were identified and matched on age, gender, date of diagnosis of IMD and followed-up-time with a control group without IMD. Demographics, clinical characteristics, mortality, and IMD-related sequelae were examined for IMD cases and compared with matched controls for a more comprehensive assessment.ResultsThe study analysed 640 IMD patients with majority of the cases diagnosed (76.9%) in a hospital setting. Age-group analysis showed a decrease in the incidence rate of IMD in patients aged <1 year (30.4 – 7.5%) and an increase in those >50 years (10.4 – 27.8%). CFR was slightly higher among females, toddlers, and adults >50 years. No significant change in CFR was observed over study period. Case-control study showed a higher number of IMD sequelae among cases compared to age- and gender-matched controls, especially in those ≥ 50 years.ConclusionThe study showed that, despite a relatively low incidence rate, IMD is responsible for a high CFR, namely in older age groups and by a high number of IMD sequelae. The study showed that leveraging data from existing databases can be used to complement surveillance data in truly assessing the epidemiology of IMD. Despite the availability of routine vaccination programs, IMD still poses a significant burden in the healthcare system of the UK. Optimization of vaccination programs may be required to reduce the disease burden.

La vaccination contre les infections invasives à méningocoque

AbstractInvasive meningococcal infections are rapidly progressive, potentially fatal and cause severe sequelae. The meningococcus is a capsulated bacterium, the composition of the capsule varies (which also determines the serogroups). Among the twelve serogroups of meningococcus, six are responsible for almost all cases but with a variable distribution worldwide and according to age. Current vaccines are prepared from capsular polysaccharide and are available against serogroup A, C, Y, and W strains. The capsular polysaccharide of meningococcus serogroup B is poorly immunogenic because of its similarity to the human neural cell adhesion molecule and cannot be used to develop a vaccine. Protein vaccines have been developed to target serogroup B strains and provide coverage for a large proportion of currently circulating strains of meningococcal B. Vaccine strategies must take into account the changing epidemiology of invasive meningococcal disease.

The Epidemiology of Meningococcal Disease and Carriage, Genotypic Characteristics and Antibiotic Resistance of Neisseria meningitidis Isolates in Zhejiang Province, China, 2011-2021.

Neisseria meningitidis (Nm) remains a worldwide leading cause of epidemic meningitis. During 2011–July 2021, 55 meningococcal disease (MD) cases were reported with a case fatality rate of 5.45% in Zhejiang Province, China. The median age was 7 years. The annual incidence was 0.0017–0.0183 per 100,000 population. The highest age-specific incidence was observed in the group younger than 1 year. Serogroup was identified in 30 laboratory-confirmed MD cases, and MenB was most predominant. MenB was mainly observed in two age groups: younger than 5 and older than 35 years. MenB incidence was significantly increasing from 0.0018 per 100,000 in 2013 to 0.0070 per 100,000 in 2019. During 2015–2020, 17 positive samples were detected from 2,827 throat swabs from healthy population, of which 70.59% was MenB. Twenty multilocus sequence typing sequence types (STs) containing eight newly assigned STs (ST15881–ST15888) were determined in all Nm isolates. Either in MD cases or in healthy population, MenB CC ST-4821 was the predominant ST. It was worth noting that two MenY CC ST-23 cases occurred in 2019 and 2021, respectively. MenY CC ST-23 MD cases increased gradually in China. Phylogeny results based on genome sequencing indicated that Chinese MenW CC ST-11 isolates were genetically linked and grouped together with Japanese isolates, separated from MenW CC ST-11 isolates from Saudi Arabia Hajj outbreak, Europe, South Africa, South America, North America, and Oceania. MenW CC ST-11 isolates from East Asia might have evolved locally. Antibiotic susceptibility tests revealed a relatively high resistance rate (22.86%) of Nm isolates to penicillin. This study provided valuable data for Chinese public health authorities to grasp the temporal epidemiological characteristics of MD and healthy carriage.

Evolution of invasive meningococcal disease epidemiology in Europe, 2008 to 2017.

BackgroundInvasive meningococcal disease (IMD) epidemiology has fluctuated over the past 25 years and varies among serogroups, age groups and geographical locations.AimThis study analysed the evolution of European IMD epidemiology from 2008 to 2017 to identify trends.MethodsReported number of IMD cases and associated incidence were extracted from the European Centre for Disease Prevention and Control Surveillance Atlas for Infectious Diseases for individual European countries. Epidemiology and its evolution were analysed by serogroup and age group.ResultsOverall IMD incidence decreased by 34.4% between 2008 and 2017. Serogroup B remained predominant in 2017; despite a 56.1% decrease over the 10-year period, the rate of decrease has slowed in recent years and varies by age group. Serogroup C was the second most prevalent serogroup until 2016. Its incidence decreased among individuals aged 1–24 years, the main population targeted by MenC vaccination campaigns, but increases have occurred in other age groups. Incidences of serogroups W and Y were low but increased by > 500% and > 130% (to 0.10 and 0.07/100,000) respectively, from 2008 to 2017. Considering all serogroups, a marked modification of the evolution trends by age group has occurred, with increases in incidence mainly affecting older age groups.ConclusionAlthough the overall IMD incidence decreased in Europe between 2008 and 2017, increases were observed for serogroups W and Y, and in the older population when considering all serogroups. It may be necessary to adapt current vaccination strategies to reflect epidemiological changes and their likely future evolution.

Genomic surveillance of Neisseria meningitidis serogroup W in Portugal from 2003 to 2019.

In recent years, a change in the epidemiology of meningococcal disease caused by Neisseria meningitidis serogroup W (MenW) has been observed worldwide, with the emergence of new sublineages associated with a higher rate of fatal cases. The present study intends to describe the epidemiology of invasive meningococcal disease (IMD) due to MenW in Portugal between 2003 and 2019, and to genetically characterize population structure. Despite MenW has a low incidence in Portugal, having almost disappeared from 2008 to 2015, since 2016, the number of MenW cases has been steadily increasing at a rate of ~ twofold per year, with more than 80% of the characterized isolates belonging to clonal complex 11 (cc11). Core-genome phylogeny of 25 Portuguese (PT) MenW isolates showed a strain clustering mainly either with the Original UK or the UK 2013 sublineages. Our study also reported for the first time the presence of distinct prophages with a notable overrepresentation of an ~ 32-35-kb PS_1-like prophage found in MenW cc11 genomes. The presence of the PS_1-like prophage in almost all 4723 cc11 genomes selected from Neisseria PubMLST database regardless of the capsular group they belong to suggests an ancestral acquisition of this mobile element prior to capsular switching events. Overall, by mimicking the scenario observed worldwide, this study reinforces the importance of a close monitoring of MenW disease, especially from cc11, in order to promptly adapt the vaccination plan for IMD control in Portugal. Moreover, future studies are needed to understand the putative contribution of prophages to fitness and virulence of PT MenW strains.

Systematic review of invasive meningococcal disease epidemiology in the Eastern Mediterranean and North Africa region

BackgroundInvasive meningococcal disease (IMD) represents a global health burden. However, its epidemiology in the Eastern Mediterranean (EM) and North Africa (NA) regions is currently not well understood. This review had four key objectives: to describe asymptomatic meningococcal carriage, IMD epidemiology (e.g. serogroup prevalence, case-fatality rates [CFRs]), IMD presentation and management (e.g. clinical diagnosis, antibiotic treatments) and economic impact and evaluation (including health technology assessment [HTA] recommendations) in EM and NA.MethodsA systematic literature search (MEDLINE and EMBASE) was conducted (January 2000 to February 2021). Search strings included meningococcal disease and the regions/countries of interest. Identified publications were screened sequentially by title/abstract, followed by screening of the full-text article; articles were also assessed on methodological quality. Literature reviews, genetic sequencing or diagnostic accuracy studies, or other non-pertinent publication type were excluded. An additional grey literature search (non-peer-reviewed sources; start date January 2000) was conducted to the end of April 2019.ResultsOf the 1745 publications identified, 79 were eligible for the final analysis (n = 61 for EM and n = 19 for NA; one study was relevant to both). Asymptomatic meningococcal carriage rates were 0–33% in risk groups (e.g. military personnel, pilgrims) in EM (no data in NA). In terms of epidemiology, serogroups A, B and W were most prevalent in EM compared with serogroups B and C in NA. IMD incidence was 0–20.5/100,000 in EM and 0.1–3.75/100,000 in NA (reported by 7/15 countries in EM and 3/5 countries in NA). CFRs were heterogenous across the EM, ranging from 0 to 57.9%, but were generally lower than 50%. Limited NA data showed a CFR of 0–50%. Data were also limited in terms of IMD presentation and management, particularly relating to clinical diagnosis/antibiotic treatment. No economic evaluation or HTA studies were found.ConclusionsHigh-risk groups remain a significant reservoir of asymptomatic meningococcal carriage. It is probable that inadequacies in national surveillance systems have contributed to the gaps identified. There is consequently a pressing need to improve national surveillance systems in order to estimate the true burden of IMD and guide appropriate prevention and control programmes in these regions.