Complications and sequelae of meningococcal disease in Quebec, Canada, 1990-1994

Longitudinal study of meningococcal carriage in adolescents and young adults in South Australia 2017-2020

BACKGROUND

This analysis investigated longitudinal changes in meningococcal carriage in adolescents in South Australia over 4 years.

METHODS

Data from the "B Part of It" study, which included a state-wide cluster randomized controlled trial in secondary-school students (n = 34,489 in 2017 and 2018) and serial cross-sectional studies in school leavers aged 17-25 years (n = 4028 in 2019-2020). Individuals had oropharyngeal swabs collected annually. This study included two unique cohorts: (1) individuals enrolled in 2019, with three consecutive annual swabs taken in 2017, 2018 and 2019; and (2) individuals enrolled in 2020, with swabs taken in 2017, 2018, and 2020. Disease-associated N. meningitidis genogroups were identified using PCR and whole genome sequencing. Univariate analysis identified risk factors for recurrent carriage (≥2).

RESULTS

Among school leavers, 50 (1.7%, total n = 2980) had carriage detected at successive visits. In participants with meningococcal carriage at successive visits, 38/50 (76.0%) had the same genogroup detected by porA PCR. Of those, 19 had the same MLST type and demonstrated minimal variation, indicating they most likely had sustained carriage of the same isolate (range 226 to 490 days, mean duration 352 [SD 51] days). In the 2019 school leaver cohort, 6.7% acquired carriage in their first year out of school compared to 3.3% in their final school year. Compared to single carriage detection, recurrent carriage was potentially more likely in older adolescents (16 compared to ≤15 years; OR = 1.97 (95%CI 1.0, 3.86); p = 0.048).

CONCLUSION

Whilst carriage is typically transient, some adolescents/young adults may have persistent carriage and are likely to be an important group in the transmission of meningococci.

Outcomes of meningococcal serogroup B disease in children after implementation of routine infant 4CMenB vaccination in England: an active, prospective, national surveillance study

BACKGROUND

In 2015, the UK included 4CMenB, a multi-component, recombinant protein-based vaccine against meningococcal serogroup B (MenB) disease, in the national infant immunisation programme. We aimed to assess the effect of 4CMenB vaccination on the severity of MenB disease presentation and outcomes.

METHODS

In this active, prospective, national surveillance study, we used data from the UK Health Security Agency national surveillance of meningococcal disease. We included data from follow-up of children younger than 5 years with laboratory-confirmed MenB disease who were eligible for 4CMenB vaccination with general practice 3-6 months after disease onset. All invasive MenB isolates were tested using the Meningococcal Antigen Typing System to determine whether the isolate was potentially preventable by 4CMenB. Admission to intensive care, death, and, when possible, reported sequelae in survivors were reviewed alongside vaccine status. For the epidemiological analysis, we compared laboratory-confirmed MenB disease cases before 4CMenB implementation (Sept 1, 2010, to March 31, 2015) with those after implementation (Sept 1, 2015, to March 31, 2020). For clinical follow-up and outcomes, we included all children younger than 5 years with laboratory-confirmed MenB disease between Sept 1, 2015, and March 31, 2021.

FINDINGS

Between Sept 1, 2015, and March 31, 2021, there were 371 cases of MenB disease in children younger than 5 years, including 256 (69%) in those younger than 1 year and 128 (35%) in those younger than 3 months. After the introduction of 4CMenB, the peak age of patients with MenB disease shifted from 5-6 months to 1-3 months. Overall, 108 (29%) of 371 children were too young for vaccination, unvaccinated, or developed MenB disease within 14 days of the first dose. Of 110 meningococcal strains characterised, 11 (92%) of 12 were potentially preventable by 4CMenB in unvaccinated children compared with 53 (66%) of 80 in partly vaccinated and 11 (69%) of 16 in fully vaccinated children. 78 (21%) of 371 children required intensive care, and the case fatality ratio was 5% (17 of 371), with 11 of 17 deaths occurring before 1 year of age, including seven in infants who were too young (<8 weeks) for vaccination. Of 354 survivors, 57 (16%) had 74 sequelae reported; 45 (61%) of 74 were neurological, 17 (23%) were physical, two (3%) were behavioural or psychological, and ten (14%) were other complications. Prevalence of sequelae was similar in unvaccinated (15 [15%] of 98) and vaccinated (42 [16%] 256) children, as were composite outcomes of death or sequelae, and intensive care or death or sequelae.

INTERPRETATION

Cases of MenB disease in vaccine-eligible children declined after 4CMenB implementation, but morbidity in vaccinated and unvaccinated children remained unchanged, highlighting the importance of vaccination to prevent MenB disease. The lower peak age of infants with MenB disease after 4CMenB implementation, with a higher case fatality ratio in young infants, highlights the importance of timely vaccination.

FUNDING

UK Health Security Agency.

Sequelae at Hospital Discharge in 61 Children With Invasive Meningococcal Disease, Chile, 2009-2019

BACKGROUND

Invasive meningococcal disease (IMD) is an unpredictable and severe infection caused by Neisseria meningitidis . Its case fatality rate could vary from 9.7% to 26% and up to 36% of survivors may experience long-term sequelae, representing a challenge for public health.

AIMED

To describe the sequelae at hospital discharge caused by IMD in children between years 2009-2019.

METHODS

Cross-sectional study performed in 2 pediatric hospitals. Patients with microbiologically confirmed diagnosis of IMD from 2009 to 2019 were included. Bivariate and logistic regression analysis were performed.

RESULTS

The records of 61 patients were reviewed and included. Sixty-seven percent were male, median age 9 months (interquartile range 4-27), 72% were admitted to intensive care unit. Thirty-seven (60.5%) had at least 1 sequela (75% and 37% in patients with or without meningitis, respectively). The most frequents sequelae were neurological 72%, hearing loss 32%, and osteoarticular 24%. Significant differences were found comparing patients with and without sequelae: drowsiness 67.6% versus 41.7% ( P = 0.04), irritability 67.6% versus 25% ( P = 0.01), meningeal signs 62.2% versus 29.2% ( P = 0.01). In logistic regression analysis, postdischarge follow-up had OR 21.25 (95% confidence intervals [CI]: 4.93-91.44), irritability had OR 8.53 (95% CI: 1.64-44.12), meningeal signs had OR 8.21 (95% CI: 0.71-94.05), invasive mechanical ventilation had OR 8.23 (95% CI: 0.78-85.95), meningitis plus meningococcemia OR 1.70 (95% CI: 0.18-15.67) to have sequelae, while children with meningococcemia and vomiting had a OR 0.04 (95% CI: 0.00-0.36) and OR 0.27 (95% CI: 0.03-2.14), respectively. N. meningitidis serogroup W (MenW) was isolated in 54.1% (33/61), and N. meningitidis serogroup B (MenB) in 31.1% (19/61) of cases. A significant difference was found in osteoarticular sequelae ( P = 0.05) between MenB and MenW. There was a decrease in cases after the meningococcal conjugate vaccine against serogroups A, C, W and Y was implemented (2015-2019).

CONCLUSIONS

IMD remains as a public health concern. A high rate of sequelae was found in pediatric patients in our series, even in the clinical manifestations other than meningitis. Neurological sequelae were the most prevalent. Multidisciplinary follow-up protocols to reduce long-term impact must be urgently established to assess all children with IMD.

4CMenB vaccine and its role in preventing transmission and inducing herd immunity

INTRODUCTION

: Vaccination is the most effective method of protecting people from invasive meningococcal disease (IMD). Of all the capsular groups, B is the most common cause of invasive meningococcal disease in many parts of the world. Despite this, adolescent meningococcal B vaccine programs have not been implemented globally, partly due to the lack of evidence for herd immunity afforded by meningococcal B vaccines.

AREAS COVERED

This review aims to synthesise the available evidence on recombinant 4CMenB vaccines' ability to reduce pharyngeal carriage and therefore provide indirect (herd) immunity against IMD.

EXPERT OPINION

There is some evidence that the 4CMenB vaccine may induce cross-protection against non-B carriage of meningococci. However, the overall body of evidence does not support a clinically significant reduction in carriage of disease-associated or group B meningococci following 4CMenB vaccination. No additional cost-benefit from herd immunity effects should be included when modelling the cost-effectiveness of 4CMenB vaccine programs against group B IMD. 4CMenB immunisation programs should focus on direct (individual) protection for groups at greatest risk of meningococcal disease.

Future meningococcal B and combination vaccines being developed should consider the impact of the vaccine on carriage as part of their clinical evaluation.

Impact of Meningococcal B Vaccine on Invasive Meningococcal Disease in Adolescents

Background

From 2017, a statewide cluster randomized trial was conducted in South Australia to assess the impact of the meningococcal B vaccine 4CMenB on pharyngeal Neisseria meningitidis carriage in adolescents. Senior schools were randomized to receive the vaccine in 2017 (intervention) or 2018 (control). In this study we report the vaccine impact of 4CMenB on serogroup B invasive meningococcal disease (IMD) in 16- to 19-year-old adolescents in South Australia.

Methods

This observational time series analysis of serogroup B IMD cases compares the 14 years prior to the commencement of the trial (2003–2016) with the 2 years following 4CMenB vaccination of the 2017 adolescent cohort.

Results

Approximately 62% of year 10 and 11 students (15–16 years old) in South Australia enrolled in the trial. A total of 30 522 year 10–12 students received at least 1 dose of 4CMenB. The number of serogroup B IMD cases in 16- to 19-year old adolescents in South Australia increased on average by 10% per year from 2003 to 2016 (95% confidence interval [CI], 6%–15%, P &lt; .001), peaking with 10 cases in 2015. Serogroup B IMD cases reduced to 5 in 2017–2018 and 1 in 2018–2019, below the expected numbers of 9.9 (95% prediction interval [PI], 3.9–17.5) and 10.9 (95% PI, 4.4–19.1), respectively. This translated to an overall reduction in the number of serogroup B IMD cases of 71% (95% CI, 15%–90%, P = .02). There were no serogroup B IMD cases in vaccinated adolescents.

Conclusions

Vaccinating adolescents with 4CMenB was associated with a reduction in group B meningococcal disease in South Australia.

Clinical Trials Registration

NCT03089086.

Why the Anti-Meningococcal B Vaccination during Adolescence Should Be Implemented in Italy: An Overview of Available Evidence

Although meningococcal disease has a low incidence in Italy, it is a public health concern owing to its high lethality rate and high frequency of transitory and/or permanent sequelae among survivors. The highest incidence rates are recorded in infants, children and adolescents, and most of the cases are due to Neisseria meningitidis B. In Italy, anti-meningococcal B (anti-MenB) vaccination is free for infants but, despite the considerable disease burden in adolescents, no national recommendation to vaccinate in this age-group is currently available. The aim of this study was to assess the main available scientific evidence to support the Italian health authorities in implementing a program of free anti-MenB vaccination for adolescents. We conducted an overview of the scientific literature on epidemiology, disease burden, immunogenicity and safety of available vaccines, and economic evaluations of vaccination strategies. Each case of invasive meningococcal disease generates a considerable health burden (lethality rate: 9%; up to 60% of patients experience at least one sequela) in terms of impaired quality of life for survivors and high direct and indirect costs (the mean overall cost of acute phase for a single case amounts to about EUR 13,952; the costs for post-acute and the long-term phases may vary widely depending of the type of sequela, reaching an annual cost of about EUR 100,000 in cases of severe neurological damage). Furthermore, vaccination against meningococcus B in adolescence proved cost-effective. The study highlights the need to actively offer the anti-MenB vaccination during adolescence at a national level. This would make it possible to avoid premature deaths and reduce the high costs borne by the National Health Service and by society of supporting survivors who suffer temporary and/or permanent sequelae.

Trajectory of serogroups causing Invasive Meningococcal Disease in Santa Catarina state, Brazil (2007–2019)

The aim of this study was to compare the trajectory of serogroups causing Invasive Meningococcal Disease (IMD) in the Santa Catarina (SC) state with those of whole Brazil. A retrospective analysis of all IMD cases reported from January 2007 to December 2019 was carried out. During the study period, 26,058 IMD cases were registered in Brazil and 644 and in SC state alone. Overall, Brazil showed progressive reduction in cases since 2010, when the meningococcal C conjugate vaccine was introducted on National Immunization Program, while SC showed an increase in total cases since 2013, particularly from serogroups W and C. Serogroups distribution was significantly different between Brazil and SC. The emergence of serogroup W highlights the improved meningococcal surveillance through increased accuracy in identification methods in SC state. This finding is important for discussing recommendations of quadrivalent (ACWY) conjugate vaccines in different geographical areas of Brazil.

Clinical and economic burden of invasive meningococcal disease: Evidence from a large German claims database

BACKGROUND

Limited data is available to describe clinical characteristics, long-term outcomes, healthcare resource use and the attributable costs of invasive meningococcal disease (IMD) in Germany. We aimed to examine demographic and clinical characteristics as well as healthcare resource use and related costs.

METHODS

We conducted a retrospective cohort study based on the InGef database in patients with IMD between 2009 and 2015. Cases were identified based on hospital main discharge diagnoses of IMD. Demographics, clinical characteristics, 30-day and 1-year mortality as well as IMD-related complications and sequelae in IMD cases were examined. In addition, short and long-term costs and healthcare resource use in IMD cases were analyzed and compared to an age- and sex-matched control group without IMD.

RESULTS

The study population comprised 164 IMD cases between 2009 and 2015. The mean length of the IMD-related hospitalization was 13 days and 38% of all cases presented with meningitis only, 35% with sepsis only, 16% with both and 11% with other IMD. The 30-day and one-year mortality were 4.3% and 5.5%, respectively. Approximately 13% of IMD cases had documented IMD-related complications at hospital discharge and 24% suffered from sequelae during follow-up. The IMD-related hospitalization was associated with mean costs of € 9,620 (standard deviation: € 22,197). The difference of mean costs between IMD cases and matched non-IMD controls were € 267 in the first month and € 1,161 from one month to one year after discharged from IMD-related hospitalization. During the later follow-up period, the mean overall costs and costs associated with individual healthcare sectors were also higher for IMD cases without reaching statistical significance.

CONCLUSIONS

IMD resulted in severe complications and sequelae and was associated with extensive costs and increased healthcare resource use in Germany, especially in the first year after IMD diagnosis and due the IMD-related hospitalization.

Human genetics of meningococcal infections

Neisseria meningitidis is a leading cause of bacterial septicaemia and meningitis worldwide. Meningococcal disease is rare but can be life threatening with a tendency to affect children. Many studies have investigated the role of human genetics in predisposition to N. meningitidis infection. These have identified both rare single-gene mutations as well as more common polymorphisms associated with meningococcal disease susceptibility and severity. These findings provide clues to the pathogenesis of N. meningitidis, the basis of host susceptibility to infection and to the aetiology of severe disease. From the multiple discoveries of monogenic complement deficiencies to the associations of complement factor H and complement factor H-related three polymorphisms to meningococcal disease, the complement pathway is highlighted as being central to the genetic control of meningococcal disease. This review aims to summarise the current understanding of the host genetic basis of meningococcal disease with respect to the different stages of meningococcal infection.

Epidemiology and Control of Meningococcal Disease in Canada: A Long, Complex, and Unfinished Story

The epidemiology of meningococcal disease in Canada has been punctuated by outbreaks caused by serogroup A strains in the 1940s, virulent serogroup C clones from 1985 to 2001, a serogroup B clone in Quebec from 2003 to 2014, and more recently a W clone in British Columbia. Region- and province-wide immunization campaigns have been implemented to control these outbreaks using meningococcal C polysaccharide and conjugate vaccines, a quadrivalent ACWY conjugate vaccine, and a serogroup B protein-based vaccine. Meningococcal C conjugate vaccines have been included in routine immunization programs for children, and ACWY conjugate vaccines have been included in school-based programs for adolescents in most jurisdictions. In contrast, serogroup B protein-based vaccines were only recommended and used for high-risk individuals and to control outbreaks. Currently, the immunization schedules adopted in provinces and territories are not uniform. This is not explained by notable epidemiologic differences. Publicly funded immunization programs are the result of a complex decision-making process. Political factors including public opinion, media attention, interest groups' advocacy campaigns, decision-makers' priorities and budgetary constraints have played important roles in shaping meningococcal programs in Canada, and this should be recognized. As the recent occurrence of outbreaks caused by virulent W clones shows, continued investments in epidemiological surveillance at both the provincial and national levels are necessary, so there can be early warning and informed decisions can be made.

Healthcare Resource Utilization and Cost of Invasive Meningococcal Disease in Ontario, Canada

BACKGROUND

Invasive meningococcal disease (IMD) is associated with significant morbidity and mortality, thus remaining a concern for healthcare providers and the public. Evidence of the longitudinal burden of IMD and associated costs are scarce. Here we have evaluated the healthcare utilization and cost associated with hospitalized IMD cases in Ontario, Canada.

METHODS

Observational cohort study utilizing the Ontario provincial claims databases, comprising: (1) individuals hospitalized with IMD between January 1995 and June 2012 and (2) age-, gender- and area-matched non-IMD controls (1:20 ratio). IMD cases were identified through diagnostic codes from hospitalization data and medical services claims. Costs are presented in Canadian dollars.

RESULTS

Nine-hundred twelve IMD cases and 18,221 non-IMD controls were included. Over 5 years of follow-up, 27% of IMD cases (excluding initial hospitalization and 30-day acute phase) versus 15% of non-IMD controls (P < 0.001) were hospitalized. Compared with controls, IMD cases were more likely to receive alternative level of care (6.7% vs. 1.1%; P < 0.001) or visit the intensive care unit (49.2% vs. 2.4%; P < 0.001), and were associated with significantly higher mean hospitalization cost per case ($40,075 vs. $2827; P < 0.001). The hospitalization cost per case remained significantly higher when excluding the initial hospitalization and acute phase ($9867 vs. $3312; P < 0.001). The mean total cost per IMD case, including medications, hospitalization and medical services, was $45,768-$52,631 ($13,520-$23,789 excluding initial hospitalization and acute phase), for an overall cost (all cases during total follow-up) of $41,740,142-$47,999,289.

CONCLUSIONS

In addition to its clinical burden, IMD is associated with significant economic burden to the public health system.

Meningococcal disease in adolescents and young adults: a review of the rationale for prevention through vaccination

Invasive meningococcal disease (IMD) caused by Neisseria meningitidis is characterized by high mortality and morbidity. While IMD incidence peaks in both infants and adolescents/young adults, carriage rates are often highest in the latter age groups, increasing IMD risk and the likelihood of transmission. Effective vaccines are available for 5 of 6 disease-causing serogroups. Because adolescents/young adults represent a significant proportion of cases, often have the highest carriage rate, and have characteristically low vaccination adherence, efforts should be focused on educating this population regarding long-term consequences of infection and the importance of meningococcal vaccination in prevention. This review describes the role of adolescents/young adults in meningococcal transmission and the clinical consequences and characteristics of IMD in this population. With a focus on countries with advanced economies that have specific meningococcal vaccination recommendations, the epidemiology of meningococcal disease and vaccination recommendations in adolescents/young adults will also be discussed.

Costs of Invasive Meningococcal Disease: A Global Systematic Review

BACKGROUND

Invasive meningococcal disease remains a public health concern because of its rapid onset and significant risk of death and long-term disability. New meningococcal serogroup B and combination serogroup ACWY vaccines are being considered for publicly funded immunization programs in many countries. Contemporary costing data associated with invasive meningococcal disease are required to inform cost-effectiveness analyses.

OBJECTIVE

The objective of this study was to estimate costs and resource utilization associated with acute infection and the long-term care of invasive meningococcal disease.

DATA SOURCES AND METHODS

PubMed, EMBASE, The Cochrane Library, health economic databases, and electronically available conference abstracts were searched. Studies reporting any costs associated with acute infection and long-term sequelae of invasive meningococcal disease in English were included. All costs were converted into purchasing power parity-adjusted estimates [international dollars (I$)] using the Campbell and Cochrane Economics Methods Group and the Evidence for Policy and Practice Information and Coordinating Centre cost converter.

RESULTS

Fourteen studies met our eligibility criteria and were included. The mean costs of acute admission ranged from I$1629 to I$50,796, with an incremental cost of I$16,378. The mean length of hospital stay was reported to be 6-18 days in multiple studies. The average costs reported for readmissions ranged from I$7905 to I$15,908. Key variables such as the presence of sequelae were associated with higher hospitalization costs and longer inpatient stay. No studies estimated direct non-healthcare costs and productivity loss. Ten studies reported only unadjusted mean values without using appropriate statistical methods for adjustment.

CONCLUSIONS

Invasive meningococcal disease can result in substantial costs to healthcare systems. However, costing data on long-term follow-up and indirect costs used to populate health economic models are lacking.

Invasive Meningococcal Disease in the Vaccine Era

Infection with the meningococcus is one of the main causes of meningitis and septicaemia worldwide. Humans are the only natural reservoir for the meningococcus which is found primarily as a commensal inhabitant in the nasopharynx in ~10% of adults, and may be found in over 25% of individuals during adolescence. Prompt recognition of meningococcal infection and early aggressive treatment are essential in order to reduce mortality, which occurs in up to 10% of those with invasive meningococcal disease (IMD). This figure may be significantly higher in those with inadequate or delayed treatment. Early administration of effective parenteral antimicrobial therapy and prompt recognition and appropriate management of the complications of IMD, including circulatory shock and raised intracranial pressure (ICP), are critical to help improve patient outcome. This review summarizes clinical features of IMD and current treatment recommendations. We will discuss the evidence for immunization and effects of vaccine strategies, particularly following implementation of effective vaccines against Group B meningococcus.

Adolescent Immunization: Challenges and Opportunities

Immunization is one of the greatest public health achievements of the past century. Vaccines are responsible for the worldwide eradication of smallpox, the elimination of polio in the western hemisphere, and most recently the elimination of rubella as a public health threat in the United States. Childhood vaccination rates are at an all-time high, but immunization falls off dramatically during adolescence (ages 11–19). With increased attention being paid to adolescent health and the new vaccines available for adolescents, efforts to increase adolescent immunization rates are moving to the forefront. Improving adolescent immunization rates requires advocacy on the part of all health professionals. School nurses, whose mission is to enhance the well-being of adolescents, are in a unique position to work with students, parents, and local health professionals to improve the adolescent immunization rate.

Cost-effectiveness Comparison of Monovalent C Versus Quadrivalent ACWY Meningococcal Conjugate Vaccination in Canada

BACKGROUND

In Quebec, 1 dose of monovalent C meningococcal conjugate vaccine (Men-C-Con) is offered at 12 months of age and a booster dose in grade 9 (14-15 years of age). In other Canadian provinces, a quadrivalent vaccine against serogroups ACWY (Men-4-Con) is increasingly used for adolescents. An economic analysis was performed to assess the value of a switch from Men-C-Con to Men-4-Con.

METHODS

A compartmental static simulation model was developed to assess the burden of invasive meningococcal disease due to serogroups AWY (AWY-IMD) in a cohort of 100,000 persons with different vaccination programs. Univariate and multivariate sensitivity analyses were performed, including variation in vaccine price difference ($12; range: $0-$20), AWY-IMD rate (0.08/100,000 to 0.28/100,000 person-years), level of herd immunity generated by adolescent vaccination (from zero to disease elimination) and discounting rate (0%, 3% or 6%).

RESULTS

In the low AWY-IMD rate base scenario, replacing Men-C-Con by Men-4-Con for adolescents would reduce disease burden by 16% (no herd effect) to 58% (moderate herd effect), with an incremental cost-effectiveness ratios between $445,000 per quality-adjusted life-year (QALY) and $167,000/QALY in a societal perspective. In the high AWY-IMD rate scenario, incremental cost-effectiveness ratio would be in the range of $97,000/QALY to $19,000/QALY.

CONCLUSION

Based on the epidemiologic conditions in Quebec and in most other Canadian provinces, the benefits of Men-4-Con in reducing the burden of disease would be low for a high cost. The switch would, however, be more economically attractive with a much higher incidence rate (as in a few provinces) or with a reduced vaccine price in conditions assuming a moderate to high herd effect.

Deciphering the Burden of Meningococcal Disease: Conventional and Under-recognized Elements

Invasive meningococcal disease remains a substantial global public health burden despite being vaccine-preventable worldwide. More than one million cases are reported annually, with average fatality rates ranging from 10% to 40% depending on clinical presentation and geographic location. Survivors may suffer debilitating sequelae that reduce the quality of life for the patient and family members responsible for their care. Major financial burdens are associated with acute treatment and follow-up care, and outbreak management often places extensive financial strains on public health resources. Although the clinical and financial aspects of meningococcal disease burden are straightforward to quantify, other burdens such as lifelong cognitive deficits, psychological stress, adaptive measures for reintegration into society, familial impact, and legal costs are systematically overlooked. These and other facets of disease burden are therefore not systematically considered in cost-effectiveness analyses that public health authorities take into consideration when making decisions regarding vaccination programs. Changing the approach for measuring meningococcal disease burden is necessary to accurately understand the societal consequences of this devastating illness. In this article, the conventional and under-recognized burdens of meningococcal disease are presented and discussed.

Cost-utility analysis of a nationwide vaccination programme against serogroup B meningococcal disease in Israel

OBJECTIVES

Using cost-utility analysis, to evaluate whether or not to adopt a Neisseria meningitidis serogroup B vaccination programme for Israeli children.

METHODS

Epidemiological, demographic, health service utilisation and economic data were integrated into a spreadsheet model to calculate the cost per averted disability-adjusted life year (DALY) of the intervention.

RESULTS

Assuming 78 % vaccine efficacy with no herd immunity, vaccination will prevent 223 cases and 22 deaths over a 100-year period. Based on vaccine price of $60 per dose, total intervention costs ($315,400,000) are partially offset by a $22,700,000 reduction in treatment and sequelae costs as a result of decreased morbidity. The intervention was not cost-effective since the net cost ($292,700,000) per averted DALY gained (1249 mostly due to decreased mortality) was $234,394. Additional two dose catch-up programmes vaccinating children in cohorts aged 1-2 to 1-13 were also not cost-effective.

CONCLUSIONS

The vaccination will become cost-effective if vaccine costs fall below $19.44 per dose. However, in identified high risk areas, the vaccine would be cost-effective and could be recommended for use both with and without catch-up campaigns.

The Burden of Pediatric Invasive Meningococcal Disease in Spain (2008-2013)

BACKGROUND

Invasive meningococcal disease remains a rare infectious disease not only with high mortality but also with important morbidity. Until recently no universal vaccine existed against serogroup B, which explains most of the cases in settings like Europe. The objective of this study was to analyze the clinical course and sequelae of meningococcal disease in Spain.

METHODS

Retrospective review of all children younger than 15 years admitted to any of the 36 hospitals in the MENDICOS Spanish network (www.mendicos.org) with confirmed or probable invasive meningococcal disease in children between January 2008 and December 2013.

RESULTS

A total of 458 cases were identified across the country, most of them occurring in previously healthy children (91.5%; n = 419/458). Median (interquartile range) age was 1.7 (0.7 and 4.6) years, with 53.1% of the cases occurring in children younger than 2 years; 82.1% (n = 368) were laboratory confirmed cases; 95.2% (n = 256) of those serogrouped were serogroup B. The diagnosis was meningitis in 24.9% (n = 114) of the cases, sepsis in 37.1% (n = 170) and both in 38.0% (n = 174). Mean hospital length of stay was 11.6 (10.9) days; 79.2% (n = 354) of the patients required pediatric intensive care unit admission, with a mean pediatric intensive care unit stay of 3.9 (4.9) days; 3.5% (n = 16) died; 12.9% (n = 59) of the survivors were discharged with some kind of physical sequelae, mainly neurological (n = 23).

CONCLUSIONS

Serogroup B invasive meningococcal infection explains substantial morbidity and mortality in Spain, occurring mainly in infants. The recent availability of a vaccine against serogroup B may change this scenario. Given that the vast majority of the cases occur in otherwise healthy children, inclusion of the meningococcal B vaccine in the national immunization program should be carefully considered.

Outcomes of bacterial meningitis in children

OBJECTIVE

Pediatricians are well aware of the immediate risks of bacterial meningitis in children. However, the long-term outcome of the disease has not been extensively studied. We aimed: (i) to evaluate the duration and quality of the long-term follow-up of children diagnosed with bacterial meningitis in a general pediatric department, (ii) to estimate the incidence of sequelae at the various stages of follow-up, and (iii) to compare our data with that of other studies.

METHODS

We conducted a retrospective study and included 34 children (3 months-15 years) who had been hospitalized for bacterial meningitis in the pediatric department of a University Hospital between January 1st, 2001 and December 31st, 2013.

RESULTS

Overall, 32% of patients presented with sequelae and 15% with seizures. Only one patient presented with hearing loss, but 23.5% of patients did not have any hearing test performed. Seven patients had a neuropsychological assessment performed and no severe neuropsychological sequela was observed in this group. The average follow-up duration increased during the study period (from 23 to 49months). The long-term follow-up modalities observed in other studies were highly variable. Assessing the incidence and severity of sequelae was therefore difficult.

CONCLUSION

A standardized follow-up should be implemented by way of a national surveillance network of children presenting with bacterial meningitis.

Characterization of invasive Neisseria meningitidis strains from Québec, Canada, during a period of increased serogroup B disease, 2009-2013: phenotyping and genotyping with special emphasis on the non-carbohydrate protein vaccine targets

BACKGROUND

The epidemiology of invasive meningococcal disease (IMD) in Québec, Canada, has been dominated in the past decade by a clone of serogroup B (MenB) Neisseria meningitidis defined by multi-locus sequence typing (MLST) as sequence type (ST)-269. With the licensure of a new MenB vaccine Bexsero (4CMenB) in Canada, this study characterized invasive N. meningitidis recovered in Québec from 2009 to 2013, with an objective to examine the diversity of the 4CMenB vaccine antigens. Isolates were serogrouped by antisera and genogrouped by PCR, and further typed by whole cell ELISA for serotype and serosubtype antigens. Clonal analysis was done by MLST. Isolates were genotyped by analysis of their 4CMenB vaccine antigen genes of PorA, factor H binding protein (fHbp), Neisserial Heparin Binding Antigen (NHBA), and Neisseria Adhesin A (NadA).

RESULTS

Of the 263 IMD isolates analysed, 229, 16, 10, 7, and 1 belonged to MenB, MenY, MenW, MenC, and MenX, respectively. Of the 229 MenB, 159 (69.4 %) were typed as ST-269 clonal complex (CC); and they possessed a restricted number of three fHbp and five nhba gene alleles. Nine N. meningitidis isolates (eight MenB and one MenY) were found to possess at least one gene that encoded for an antigen that matched exactly with protein variants in the 4CMenB vaccine. Two MenB expressed PorA antigen P1.4 and possessed the nhba gene for peptide 2; four other MenB were predicted to have NHBA peptide 2; another two MenB were predicted to encode fHbp peptide 1.1; and a single MenY was found to have nadA gene for NadA peptide 8. In addition, another 172 isolates were found to possess genes for variant 1 fHbp peptides other than peptide 1.1 or NadA variant 1-2/3 peptides other than peptide 8; and therefore, may potentially be covered by 4CMenB.

CONCLUSION

The most prevalent clone of N. meningitidis in Quebec was ST-269 CC; and 96 % of the isolates in this CC were predicted to be covered by 4CMenB vaccine. Extensive genetic diversity was found in the other IMD isolates in Québec which might suggest a lower coverage by the vaccine when compared to the ST-269 MenB.

Clinical and Cost-Effectiveness of Procalcitonin Test for Prodromal Meningococcal Disease-A Meta-Analysis

Background

Despite vaccines and improved medical intensive care, clinicians must continue to be vigilant of possible Meningococcal Disease in children. The objective was to establish if the procalcitonin test was a cost-effective adjunct for prodromal Meningococcal Disease in children presenting at emergency department with fever without source.

Methods and Findings

Data to evaluate procalcitonin, C-reactive protein and white cell count tests as indicators of Meningococcal Disease were collected from six independent studies identified through a systematic literature search, applying PRISMA guidelines. The data included 881 children with fever without source in developed countries.The optimal cut-off value for the procalcitonin, C-reactive protein and white cell count tests, each as an indicator of Meningococcal Disease, was determined. Summary Receiver Operator Curve analysis determined the overall diagnostic performance of each test with 95% confidence intervals. A decision analytic model was designed to reflect realistic clinical pathways for a child presenting with fever without source by comparing two diagnostic strategies: standard testing using combined C-reactive protein and white cell count tests compared to standard testing plus procalcitonin test. The costs of each of the four diagnosis groups (true positive, false negative, true negative and false positive) were assessed from a National Health Service payer perspective. The procalcitonin test was more accurate (sensitivity=0.89, 95%CI=0.76-0.96; specificity=0.74, 95%CI=0.4-0.92) for early Meningococcal Disease compared to standard testing alone (sensitivity=0.47, 95%CI=0.32-0.62; specificity=0.8, 95% CI=0.64-0.9). Decision analytic model outcomes indicated that the incremental cost effectiveness ratio for the base case was £-8,137.25 (US $ -13,371.94) per correctly treated patient.

Conclusions

Procalcitonin plus standard recommended tests, improved the discriminatory ability for fatal Meningococcal Disease and was more cost-effective; it was also a superior biomarker in infants. Further research is recommended for point-of-care procalcitonin testing and Markov modelling to incorporate cost per QALY with a life-time model.

Glycoconjugate vaccines: an update

INTRODUCTION

Globally, the three main pathogens causing serious infections are Haemophilus influenzae type b, Streptococcus pneumoniae and Neisseria meningitidis. Over the last 5 years, new vaccines protecting against these bacteria have been developed and introduced in various countries.

AREAS COVERED

This review describes the recently licensed glycoconjugates being used to protect against these encapsulated bacteria. Immunogenicity and safety data that led to licensure or licensure expansion of these glycoconjugates are discussed in addition to the resultant impact on the disease burden.

EXPERT OPINION

The maintenance of robust immunisation programmes with high uptake rates is important in maintaining low rates of disease. Epidemiological surveillance systems are essential in monitoring any changes in infectious disease trends and in identifying emerging infections such as from non-typeable H. influenzae, pneumococcal serotype replacement disease and changes in the epidemiology of meningococcal serogroups. This is important to guide future vaccine development. Accessibility of these glycoconjugate vaccines in resource poor regions, which bear the highest disease burden from these pathogens, remains challenging largely due to high vaccine pricing. Recent aids from public and private funding, tiered vaccine pricing and the transfer of vaccine technology have helped in introducing these vaccines where they are most needed.

Re-evaluating cost effectiveness of universal meningitis vaccination (Bexsero) in England: modelling study

OBJECTIVE

To use mathematical and economic models to predict the epidemiological and economic impact of vaccination with Bexsero, designed to protect against group B meningococcal disease, to help inform vaccine policy in the United Kingdom.

DESIGN

Modelling study.

SETTING

England.

POPULATION

People aged 0-99.

INTERVENTIONS

Incremental impact of introductory vaccine strategies simulated with a transmission dynamic model of meningococcal infection and vaccination including potential herd effects. Model parameters included recent evidence on the vaccine characteristics, disease burden, costs of care, litigation costs, and loss of quality of life from disease, including impacts on family and network members. The health impact of vaccination was assessed through cases averted and quality adjusted life years (QALYs) gained.

MAIN OUTCOME MEASURES

Cases averted and cost per QALY gained through vaccination; programmes were deemed cost effective against a willingness to pay of £20,000 (€25,420, $32,677) per QALY gained from an NHS and personal and social services perspective.

RESULTS

In the short term, case reduction is greatest with routine infant immunisation (26.3% of cases averted in the first five years). This strategy could be cost effective at £3 (€3.8, $4.9) a vaccine dose, given several favourable assumptions and the use of a quality of life adjustment factor. If the vaccine can disrupt meningococcal transmission more cases are prevented in the long term with an infant and adolescent combined programme (51.8% after 30 years), which could be cost effective at £4 a vaccine dose. Assuming the vaccine reduces acquisition by 30%, adolescent vaccination alone is the most favourable strategy economically, but takes more than 20 years to substantially reduce the number of cases.

CONCLUSIONS

Routine infant vaccination is the most effective short term strategy and could be cost effective with a low vaccine price. Critically, if the vaccine reduces carriage acquisition in teenagers, the combination of infant and adolescent vaccination could result in substantial long term reductions in cases and be cost effective with competitive vaccine pricing.

The inpatient costs and hospital service use associated with invasive meningococcal disease in South Australian children

BACKGROUND

Invasive meningococcal disease (IMD) remains a serious public health concern due to a sustained high case fatality rate and morbidity in survivors. This study aimed to estimate the hospital service costs associated with IMD and variables associated with the highest costs in Australian children admitted to a tertiary paediatric hospital.

METHODS

Clinical details were obtained from medical records and associated inpatient costs were collected and inflated to 2011 Australian dollars using the medical and hospital services component of the Australian Consumer Price Index. Both unadjusted and adjusted analyses were undertaken. Multivariate regression models were used to adjust for potential covariates and determine independent predictors of high costs and increased length of hospital stay.

RESULTS

Of 109 children hospitalised with IMD between May 2000 and April 2011, the majority were caused by serogroup B (70.6%). Presence of sequelae, serogroup B infection, male gender, infants less than one year of age, and previous medical diagnosis were associated with higher inpatient costs and length of stay (LOS) in hospital (p<0.001) during the acute admissions. Children diagnosed with septicaemia had a longer predicted LOS (p=0.033) during the acute admissions compared to those diagnosed with meningitis alone or meningitis with septicaemia. Serogroup B cases incurred a significantly higher risk of IMD related readmissions (IRR: 21.1, p=0.008) for patients with sequelae. Serogroup B infection, male gender, diagnosis of septicaemia, infants less than one year of age, and no previous medical diagnosis were more likely to have higher inpatient costs and LOS during the IMD related readmissions for patients with sequelae (p<0.05).

CONCLUSION

Although IMD is uncommon, the disease severity and associated long-term sequelae result in high health care costs, which should be considered in meningococcal B vaccine funding considerations.

Persistence of serogroup C antibody responses following quadrivalent meningococcal conjugate vaccination in United States military personnel

Serogroup C meningococcal (MenC) disease accounts for one-third of all meningococcal cases and causes meningococcal outbreaks in the U.S. Quadrivalent meningococcal vaccine conjugated to diphtheria toxoid (MenACYW_D) was recommended in 2005 for adolescents and high risk groups such as military recruits. We evaluated anti-MenC antibody persistence in U.S. military personnel vaccinated with either MenACYW_D or meningococcal polysaccharide vaccine (MPSV4). Twelve hundred subjects vaccinated with MenACYW_D from 2006 to 2008 or MPSV4 from 2002 to 2004 were randomly selected from the Defense Medical Surveillance System. Baseline serologic responses to MenC were assessed in all subjects; 100 subjects per vaccine group were tested during one of the following six post-vaccination time-points: 5–7, 11–13, 17–19, 23–25, 29–31, or 35–37 months. Anti-MenC geometric mean titers (GMT) were measured by rabbit complement serum bactericidal assay (rSBA) and geometric mean concentrations (GMC) by enzyme-linked immunosorbent assay (ELISA). Continuous variables were compared using the Wilcoxon rank sum test and the proportion of subjects with an rSBA titer ≥8 by chi-square. Pre-vaccination rSBA GMT was <8 for the MenACWY_D group. rSBA GMT increased to 703 at 5–7 months post-vaccination and decreased by 94% to 43 at 3 years post-vaccination. GMT was significantly lower in the MenACWY_D group at 5–7 months post-vaccination compared to the MPSV4 group. The percentage of MenACWY_D recipients achieving an rSBA titer of ≥8 decreased from 87% at 5–7 months to 54% at 3 years. There were no significant differences between vaccine groups in the proportion of subjects with a titer of ≥8 at any time-point. GMC for the MenACWY_D group was 0.14 µg/mL at baseline, 1.07 µg/mL at 5–7 months, and 0.66 µg/mL at 3 years, and significantly lower than the MPSV4 group at all time-points. Anti-MenC responses wane following vaccination with MenACYW_D; a booster dose is needed to maintain protective levels of circulating antibody.

The burden and impact of severe and long-term sequelae of meningococcal disease

This review describes current knowledge on the severity and long-term sequelae of meningococcal disease (MD) specifically. The literature databases Medline and Embase were used by combining search terms for MD and Neisseria meningitidis with terms for severity, mortality and sequelae. Case fatality for sufferers of MD remains high, typically 5-10%, despite the best medical care. Long-term sequelae in survivors may include physical, neurological, cognitive, behavioral and psychological consequences, such as hearing loss, amputations, skin scarring and neurodevelopmental deficits. A significantly lower quality of life is seen in survivors of MD compared with unaffected controls, with detrimental effects of childhood MD continuing into adulthood. MD carries a substantial risk of long-term sequelae and mortality. This should be recognized by physicians treating patients with this disease and lends support for the implementation of preventative measures such as vaccination.

Introducing vaccination against serogroup B meningococcal disease: an economic and mathematical modelling study of potential impact

BACKGROUND

Meningococcal disease remains an important cause of morbidity and mortality worldwide. The first broadly effective vaccine against group B disease (which causes considerable meningococcal disease in Europe, the Americas and Australasia) was licensed in the EU in January 2013; our objective was to estimate the potential impact of introducing such a vaccine in England.

METHODS

We developed two models to estimate the impact of introducing a new 'MenB' vaccine. The cohort model assumes the vaccine protects against disease only; the transmission dynamic model also allows the vaccine to protect against carriage (accounting for herd effects). We used these, and economic models, to estimate the case reduction and cost-effectiveness of a number of different vaccine strategies.

RESULTS

We estimate 27% of meningococcal disease cases could be prevented over the lifetime of an English birth cohort by vaccinating infants at 2,3,4 and 12 months of age with a vaccine that prevents disease only; this strategy could be cost-effective at £9 per vaccine dose. Substantial reductions in disease (71%) can be produced after 10 years by routinely vaccinating infants in combination with a large-scale catch-up campaign, using a vaccine which protects against carriage as well as disease; this could be cost-effective at £17 per vaccine dose.

CONCLUSIONS

New 'MenB' vaccines could substantially reduce disease in England and be cost-effective if competitively priced, particularly if the vaccines can prevent carriage as well as disease. These results are relevant to other countries, with a similar epidemiology to England, considering the introduction of a new 'MenB' vaccine.

Challenges to the surveillance of meningococcal disease in an era of declining incidence in montréal, Québec

OBJECTIVES

Though rare in Montréal, meningococcal disease continues to cause serious morbidity and mortality. In an era of declining incidence, our objective was to evaluate the sensitivity and the timeliness of case reporting and the capacity to statistically detect disease clusters.

METHODS

We used the public health department's reportable disease database (RDD) to calculate the timeliness of reporting by physicians and laboratories for the period 1995 to 2008. The sensitivity of case reporting was evaluated through capture-recapture estimation using the RDD and the hospitalization discharge database (MED-ECHO). To evaluate the detection of cases clustered by time and proximity, we applied scan statistics to the RDD with cases coded by time and geographic location for the period 1992 to 2008.

RESULTS

While the system sensitivity was judged to be high at 94%, physicians reported only 54% of cases. A total of 92.3% of cases were notified by physicians or laboratories within seven days, meaning that in theory, 13 cases were not notified in time to conduct thorough contact tracing and offer chemoprophylaxis to close contacts. In high-incidence years, scan statistics detected two statistically-significant clusters one to two weeks earlier than traditional detection through the manual monitoring of cumulative cases.

CONCLUSIONS

To improve system performance, we recommended increasing the emphasis of laboratory reporting, reinforcing early reporting by physicians and if incidence increases, using scan statistics to identify clusters that can add to a public health practitioner's initial "hunch" of an emerging outbreak.

A new scoring system derived from base excess and platelet count at presentation predicts mortality in paediatric meningococcal sepsis

INTRODUCTION

The aim of this study was to derive a novel prognostic score for mortality in paediatric meningococcal sepsis (MS) based on readily available laboratory markers.

METHODS

A multicentre retrospective cohort study for the consortium set and a single centre retrospective study for replication set. The consortium set were 1,073 children (age 1 week to 17.9 years) referred over a 15-year period (1996 to 2011), who had an admission diagnosis of MS, referred to paediatric intensive care units (PICUs) in six different European centres. The consortium set was split into a development set and validation set to derive the score. The replication set were 134 children with MS (age 2 weeks to 16 years) referred over a 4-year period (2007 to 2011) to PICUs via the Children's Acute Transport Service (CATS), London.

RESULTS

A total of 85/1,073 (7.9%) children in the consortium set died. A total of 16/134 (11.9%) children in the replication set died. Children dying in the consortium set had significantly lower base excess, C-reactive protein (CRP), platelet and white cell count, more deranged coagulation and higher lactate than survivors. Paediatric risk of mortality (PRISM) score, Glasgow meningococcal septicaemia prognosis score (GMSPS) and Rotterdam score were also higher. Using the consortium set, a new scoring system using base excess and platelet count at presentation, termed the BEP score, was mathematically developed and validated. BEP predicted mortality with high sensitivity and specificity scores (area under the curve (AUC) in the validation set=0.86 and in the replication set=0.96). In the validation set, BEP score performance (AUC=0.86, confidence interval (CI): 0.80 to 0.91) was better than GMSPS (AUC=0.77, CI: 0.68, 0.85), similar to Rotterdam (AUC=0.87, CI: 0.81 to 0.93) and not as good as PRISM (AUC=0.93, CI: 0.85 to 0.97).

CONCLUSIONS

The BEP score, relying on only two variables that are quickly and objectively measurable and readily available at presentation, is highly sensitive and specific in predicting death from MS in childhood.

Parents' experiences of support during and after their child's diagnosis of meningococcal disease

AIM

To understand parents'/carers' experiences of support received following their child's diagnosis of invasive meningococcal serogroup B disease (MenB).

METHODS

Structured interviews with parents/carers of 244 survivors of MenB disease in childhood, drawn from a population-based case-control study.

RESULTS

Responses indicated that optimal support should encompass the whole treatment pathway, beginning with fast and accurate recognition of MenB by clinicians, followed by the provision of information about the symptoms and possible sequelae of MenB, better communication about the treatment process and disease progression and greater follow-up care.

CONCLUSION

Parents' experience of support following their child's diagnosis of MenB could be significantly enhanced through better education and enhanced knowledge in health care professionals, improved access to information about short- and long-term sequelae and easier access to follow-up support and advice. Much of the data generated pertained to situations and processes common to most serious illnesses occurring in children and therefore it is likely that these findings pose wider questions about support and communication in paediatrics.

Counting the cost of meningococcal disease : scenarios of severe meningitis and septicemia

BACKGROUND

Meningococcal disease can result in severe disabling sequelae, but there is no published information about the lifelong rehabilitation costs of patients with severe outcome in the UK. As cost-effectiveness studies play a crucial role in determining whether immunization programmes will be implemented, it is important to identify these costs.

OBJECTIVE

The aim of the study was to estimate lifelong rehabilitation costs associated with severe cases of meningococcal disease and to present these costs in a format appropriate for use in a cost-effectiveness analysis.

METHODS

Two severe scenarios of meningococcal disease with major sequelae were developed; one that presented acutely as meningitis and the other as septicemia. Scenarios were based on systematic reviews of the literature describing the sequelae of meningococcal disease, dialogue with Meningitis Research Foundation members who have experience of the disease, and discussions with pediatricians who have been responsible for managing children with this disease over many years. The two scenarios were devised to represent cases typical of the severe end of the spectrum. To obtain a comprehensive list of the health, educational and other resources used by survivors during and since their acute illness, families of individuals with sequelae similar to those in each of our scenarios were interviewed. Relevant academics and professionals in health, social care and education were consulted in order to ensure that our scenarios accurately represented the treatment and support that individuals with such sequelae might realistically receive from the National Health Service (NHS), the local authority and Personal Social Services (PSS). The majority of costs were derived from English Department of Health reference costs and unit costs of health and social care reflecting values for the financial year 2008-2009 indexed to 2010-2011. Costs were based on a life expectancy of 70 years in each scenario and are presented at a discount rate of 3.5 % for the first 30 years and 3 % thereafter, as recommended by the UK treasury (non-discounted costs are also presented for comparison). Costs are presented from both an NHS/PSS perspective and a government perspective.

RESULTS

This study has revealed that severe cases of disease that result in long-term sequelae can result in costs to the NHS/PSS of around £160,000-£200,000 in the first year alone. Over a lifetime of 70 years, discounted costs from an NHS/PSS perspective ranged from approximately £590,000 to £1,090,000 (£1,250,000-£3,320,000 undiscounted) and discounted costs from a government perspective ranged from £1,360,000 to £1,720,000 (£3,030,000-£4,470,000 undiscounted).

CONCLUSION

This study fills a gap in the UK literature and produces estimates that can be used in cost-effectiveness analysis to better represent the cost of illness at the severe end of the spectrum. Costs from a government perspective highlight the wider impacts of this disease, which is important for clinical decision makers, and budgetary and service planners to be aware of when making decisions about the benefits of implementing public health interventions such as immunization programmes.

The disease burden of invasive meningococcal serogroup B disease in Canada

BACKGROUND

Invasive meningococcal disease remains a rare but deadly infection in Canada. New serogroup B vaccines may offer the potential for prevention and control. This report examines the disease burden caused by serogroup B invasive meningococcal infections.

METHODS

From 2002 to 2011, active, population-based metropolitan area surveillance for adult and pediatric hospital admissions for adult and pediatric hospital admissions for laboratory-confirmed infection with Neisseria meningitidis, was conducted by the 12 centers of the Canadian Immunization Monitoring Program, Active.

RESULTS

A total of 769 invasive meningococcal cases occurred from 2002 to 2011; 54% (n = 413) in children with a peak incidence of 6.16 (95% confidence interval: 3.18-10.76) per 100,000 in children aged <1 year in 2009. Serogroup B accounted for the largest proportion of cases and had the highest incidence of all serogroups across all ages, with a peak incidence of 0.31 (0.23-0.40) per 100,000 in 2007. Serogroup B case fatality rate was 4.3% in children, and 21% of pediatric survivors had sequelae. B:17:P1.19 ST-269 was the most frequently detected antigenic type.

CONCLUSIONS

Serogroup B invasive meningococcal infections caused substantial morbidity and mortality and are the leading cause of invasive meningococcal disease in Canada. The proportion of cases potentially preventable with the new serogroup B vaccines should be evaluated to determine whether universal immunization programs are warranted.

The changing epidemiology of meningococcal disease in Quebec, Canada, 1991-2011: potential implications of emergence of new strains

Background

In order to inform meningococcal disease prevention strategies, we analysed the epidemiology of invasive meningococcal disease (IMD) in the province of Quebec, Canada, 10 years before and 10 years after the introduction of serogroup C conjugate vaccination.

Methodology

IMD cases reported to the provincial notifiable disease registry in 1991–2011 and isolates submitted for laboratory surveillance in 1997–2011 were analysed. Serogrouping, PCR testing and assignment of isolates to sequence types (ST) by using multilocus sequence typing (MLST) were performed.

Results

Yearly overall IMD incidence rates ranged from 2.2–2.3/100,000 in 1991–1992 to 0.49/100,000 in 1999–2000, increasing to 1.04/100,000 in 2011. Among the 945 IMD cases identified by laboratory surveillance in 1997–2011, 68%, 20%, 8%, and 3% were due to serogroups B, C, Y, and W135, respectively. Serogroup C IMD almost disappeared following the implementation of universal childhood immunization with monovalent C conjugate vaccines in 2002. Serogroup B has been responsible for 88% of all IMD cases and 61% of all IMD deaths over the last 3 years. The number and proportion of ST-269 clonal complex has been steadily increasing among the identified clonal complexes of serogroup B IMD since its first identification in 2003, representing 65% of serogroup B IMD in 2011. This clonal complex was first introduced in adolescent and young adults, then spread to other age groups.

Conclusion

Important changes in the epidemiology of IMD have been observed in Quebec during the last two decades. Serogroup C has been virtually eliminated. In recent years, most cases have been caused by the serogroup B ST-269 clonal complex. Although overall burden of IMD is low, the use of a vaccine with potential broad-spectrum coverage could further reduce the burden of disease. Acceptability, feasibility and cost-effectiveness studies coupled with ongoing clinical and molecular surveillance are necessary in guiding public policy decisions.

From genes to vaccine: A breakthrough in the prevention of meningococcal group B disease

Although safe and effective vaccines exist for meningococcal serogroups A, C, W-135 and Y, no vaccine is available for routine use against disease caused by serogroup B (MenB). Consequently, MenB is now the most common cause of invasive meningococcal disease in Canada. MenB causes more than 80% of invasive meningococcal disease in infants and can occur at any age. The mortality and morbidity rates related to this disease are very high. Vaccine development against MenB has been hampered by the fact that MenB polysaccharide is not immunogenic in humans. Although vaccines derived from the outer membrane vesicle have been effective in controlling MenB outbreaks, such vaccines protect against the outbreak strain only. A new vaccine development strategy, reverse vaccinology, has led to the identification of genes coding for surface-exposed proteins, which are able to induce bactericidal antibodies against a broad range of MenB strains. A new vaccine containing a combination of these proteins has been tested in different age groups, in several clinical trials. The data available provide hope that control of MenB through routine vaccination will soon be possible.

Meningococcal disease: clinical presentation and sequelae

The clinical spectrum of invasive meningococcal disease is diverse with meningitis and/or septicaemia being the commonest modes of presentation. The severity of manifestations of meningococcal infection ranges from bacteraemia, associated with mild non-specific symptoms, to fulminant sepsis with multiorgan failure and death in approximately 10-15% of cases. Localised infections (such as conjunctivitis or septic arthritis) as well as chronic disease may be the sole clinical manifestations but can also lead to disseminated fulminant disease. Among survivors, disabling long-term sequelae can complicate meningococcal disease and result in potentially devastating effects on the quality of life of survivors, most of whom are infants, children and adolescents. The only rational approach to the prevention of meningococcal disease and the associated human suffering is through vaccination.

Invasive meningococcal capsular group Y disease, England and Wales, 2007-2009

Increases may result from mutations that allow the organism to evade the immune system.

Enhanced national surveillance for invasive meningococcal disease in England and Wales identified an increase in laboratory-confirmed capsular group Y (MenY) disease from 34 cases in 2007 to 44 in 2008 and 65 in 2009. For cases diagnosed in 2009, patient median age at disease onset was 60 years; 39% of patients had underlying medical conditions, and 19% died. MenY isolates causing invasive disease during 2007–2009 belonged mainly to 1 of 4 clonal complexes (cc), cc23 (56% of isolates), cc174 (21%), cc167 (11%), and cc22 (8%). The 2009 increase resulted primarily from sequence type 1655 (cc23) (22 cases in 2009, compared with 4 cases each in 2007 and 2008). cc23 was associated with lpxL1 mutations and meningitis in younger age groups (<25 years); cc174 was associated with nonmeningitis, particularly pneumonia, in older age groups (>65 years). The increase in MenY disease requires careful epidemiologic and molecular monitoring.

Consensus recommendation for meningococcal disease prevention in children and adolescents in the Middle East region

Facing the availability of the new generation of quadrivalent meningococcal conjugate vaccines (Menveo®, Menactra® and others pending for license) and their recent implementation in Saudi Arabia, experts from 11 countries of the Middle East region met at a “Meningococcal Leadership Forum” (MLF), which took place in May 2010 in Dubai. The participants of the conference discussed the importance of introducing the concept of conjugate vaccines – especially for children and adolescents – and elaborated a consensus recommendation to support healthcare professionals and decision makers with their expertise. In experts’ opinion, conjugate vaccines are the best choice for the prevention of meningococcal disease caused by serogroups A, C, W-135 and Y. As quadrivalent meningococcal conjugate vaccines are registered and available in the Middle East region, they should replace plain polysaccharide vaccines and be integrated in pediatric and adolescent vaccination schedules, including infant vaccination concomitantly with basic EPI vaccines when licensed.

Meningococcal disease serogroup C

Despite current advances in antibiotic therapy and vaccines, meningococcal disease serogroup C (MDC) remains a serious threat to global health, particularly in countries in North and Latin America, Europe, and Asia. MDC is a leading cause of morbidity, mortality, and neurological sequelae and it is a heavy economic burden. At the individual level, despite advances in antibiotics and supportive therapies, case fatality rate remains nearly 10% and severe neurological sequelae are frequent. At the population level, prevention and control of infection is more challenging. The main approaches include health education, providing information to the public, specific treatment, chemoprophylaxis, and the use of vaccines. Plain and conjugate meningococcal C polysaccharide vaccines are considered safe, are well tolerated, and have been used successfully for over 30 years. Most high-income countries use vaccination as a part of public health strategies, and different meningococcal C vaccination schedules have proven to be effective in reducing incidence. This is particularly so with conjugate vaccines, which have been found to induce immunogenicity in infants (the age group with the highest incidence rates of disease), stimulate immunologic memory, have longer effects, not lead to hyporesponsiveness with repeated dosing, and decrease acquisition of nasopharyngeal carriage, inducing herd immunity. Antibiotics are considered a cornerstone of MDC treatment and must be administered empirically as soon as possible. The choice of which antibiotic to use should be made based on local antibiotic resistance, availability, and circulating strains. Excellent options for a 7-day course are penicillin, ampicillin, chloramphenicol, and third-generation cephalosporins (ceftriaxone and cefotaxime) intravenously, although the latter are considerably more expensive than the others. The use of steroids as adjunctive therapy for MDC is still controversial and remains a topic of debate. A combination of all of the aforementioned approaches is useful in the prevention and control of MDC, and each country should tailor its public health policy to its own particular needs and knowledge of disease burden.