Epidemiology of meningococcal disease in Latin America: current situation and opportunities for prevention

Economic burden of meningococcal disease in children and adolescents in Tijuana, Mexico

Invasive meningococcal disease (IMD) is an uncommon but serious and potentially fatal condition mainly affecting children and adolescents. Active surveillance between 2005 and 2016 at Tijuana General Hospital, Mexico, indicated that the incidence of IMD in Tijuana was higher than previously thought, at 2.69 per 100,000 population aged <16 years. The objective of this study was to estimate the economic burden associated with 51 IMD cases in children aged <16 years identified over the 11 years of active surveillance at Tijuana General Hospital, Mexico. Healthcare resource usage for the IMD cases was obtained from the hospital database and combined with unit costs from the hospital purchasing department or national databases to estimate total healthcare costs over a follow-up period of 3 months. Societal costs were represented by the value of lost wages for parents or guardians. All costs were expressed in US$. Over the 11-year study period there were 51 IMD cases, of which 13 (25%) were fatal. The total cost for all 51 cases over the 11-year study period was US$1,054,499 (average per case US$20,676), of which direct healthcare costs comprised US$1,029,948 (average per case US$20,195) and societal costs US$24,551 (average per case US$481). Extrapolated to the population of Tijuana region aged <16 years, the estimated annual economic burden of IMD was US$268,794. The major cost driver was the cost of hospitalization. These data illustrate the significant economic burden associated with IMD in Tijuana, and will be useful in assessing optimal vaccination programs against meningococcal disease in Mexico.

Phase I safety and immunogenicity study of a Brazilian serogroup B vaccine

Meningococcal disease by serogroup B has been a public health problem in Brazil in the last decades. The Brazilian Oswaldo Cruz Foundation has been working to develop a vaccine with detergent-treated outer membrane vesicles (OMV) and detoxified endotoxin (dLOS) from Neisseria meningitidis serogroup B prevalent strains. A phase I study, enrolling 26 adults (18–44 years of age) was performed using experimental vaccines combining B components and aluminum hydroxide as adjuvant. It was a dose escalation study testing vaccines made of 25, 50, and 100 µg OMV protein/mL (sum of both strains) and dLOS in half amount of total protein concentration, with three doses given two months apart. Adverse events were mild/moderate with frequency increasing with the amount of antigens. Pain in the site of injection was the most frequent reaction in all doses, reported in more than the 85% across vaccine groups. Considering all injections, cephalea was the most common systemic adverse event, detected in 11.1%, 17.2% and 32.1%, respectively with doses of 12.5 μg, 25 μg and 50 μg. High titers of total IgG (ELISA) were observed for the vaccine components before vaccination. Protective levels of bactericidal antibodies (titer ≥1:4) for both vaccine strains were also present. Considering a 4-fold increase of IgG titers compared to pre-immune values (seroconversion), 50%-70% of those who received intermediate and highest doses of antigens presented satisfactory response for OMV of N44/89 strain. The lowest dose vaccine induced no seroconversion for strain N44/89, and 11% for strain N603/95. For the three vaccines doses, 25% of seroconversion, in total IgG against LOS, was observed. Increased antibody bactericidal activity was observed for both strains in higher antigen concentrations. For IgG against LOS, all vaccine formulations showed 25% of seroconversion. In conclusion, MenB-Bio experimental vaccines were well tolerated and immunogenic, thus allowing phase II studies.

The Impact of Haemophilus Influenzae and Streptococcus Pneumoniae Vaccination in Bacterial Meningitis in a Pediatric Referral Hospital in Mexico

Objective This study aimed to compare the epidemiology of bacterial meningitis (BM) before and after vaccination, and identify possible risk factors associated with mortality.

Methods The medical and microbiologic records of children (1 month–18 years) with a discharge diagnosis of BM in a third level children's hospital in Mexico from 1990 to 2018 were reviewed. The epidemiology, pathogens, and outcomes were compared before and after introducing Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines to the Mexican immunization schedule. Risk factors associated with mortality were determined.

Results In the 28-year period, 226 cases with BM were included 55.8% (1990–1999), 27.4% (2000–2008), and 16.8% (2009–2018) (p = 0.0001). The most frequent pathogen was Hib, documented in 39% of cases. There was a reduction in neurological complications after introducing the Hib conjugate vaccine (59 vs. 39%; p = 0.003) and sequelae after the Streptococcus pneumoniae conjugate vaccine (43 vs. 35%; p = 0.05). Independent risk factors associated with mortality were coma (odds ratio [OR]: 15 [2.9–78]), intracerebral bleeding (OR: 3.5 [1.4–12]), and pneumococcal meningitis (OR: 9.4 [2.2–39]).

Conclusion Since the introduction of Hib and pneumococcal conjugate vaccines to the national immunization schedule, there was a reduction in BM cases, mainly associated with the Hib vaccine, with the consequent reduction of neurological complications and sequelae.

A Narrative Review of the W, X, Y, E, and NG of Meningococcal Disease: Emerging Capsular Groups, Pathotypes, and Global Control

Neisseria meningitidis, carried in the human nasopharynx asymptomatically by ~10% of the population, remains a leading cause of meningitis and rapidly fatal sepsis, usually in otherwise healthy individuals. The epidemiology of invasive meningococcal disease (IMD) varies substantially by geography and over time and is now influenced by meningococcal vaccines and in 2020–2021 by COVID-19 pandemic containment measures. While 12 capsular groups, defined by capsular polysaccharide structures, can be expressed by N. meningitidis, groups A, B, and C historically caused most IMD. However, the use of mono-, bi-, and quadrivalent-polysaccharide-conjugate vaccines, the introduction of protein-based vaccines for group B, natural disease fluctuations, new drugs (e.g., eculizumab) that increase meningococcal susceptibility, changing transmission dynamics and meningococcal evolution are impacting the incidence of the capsular groups causing IMD. While the ability to spread and cause illness vary considerably, capsular groups W, X, and Y now cause significant IMD. In addition, group E and nongroupable meningococci have appeared as a cause of invasive disease, and a nongroupable N. meningitidis pathotype of the hypervirulent clonal complex 11 is causing sexually transmitted urethritis cases and outbreaks. Carriage and IMD of the previously “minor” N. meningitidis are reviewed and the need for polyvalent meningococcal vaccines emphasized.

Long-term impacts of MenC vaccination campaign in the Salvador, Brazil metropolitan region: A comparison of pre- and post-vaccine periods

The Meningococcal Serogroup C Conjugate Vaccine (MenC) was introduced into the Brazilian Immunization Program in 2010. However, in Salvador, the fourth largest capital in Brazil, an extended catch-up campaign was conducted earlier in that year, which focused on adolescents and young adults aged 10-24 years. To evaluate the long-term impact of MenC vaccination, we analyzed hospital-based surveillance data on cases of meningococcal disease in the Salvador metropolitan region during the pre-vaccine (2005-2009) and post-vaccine (2011-2016) campaign periods. Six years after the introduction of the MenC vaccine, the mean incidence rate decreased from 3.20 to 0.93 cases per 100,000 individuals (71% reduction, 95% CI [58.7-83.3]) in children <4 years. Reductions of 25.6% and 21.1% were also observed for the age groups of 5-9 and 10-14 years, respectively. On the other hand, incidence increased in the 15-24-year age group from 0.72 to 1.11, and from 0.31 to 0.60 in individuals aged >25 years (p < 0.05). At the end of the study period, serogroup C was the most prevalent (65.7%), followed by serogroups B (9.8%), W (2.3%), Y (1.6%) and A (1.0%); serogrouping was not possible in 19.6% of the cases, or adequate material was not available for serogroup identification. The use of real-time PCR from 2010 onwards increased detection rates of meningococcal meningitis by 29.6%. The long-term impact of the MenC vaccination campaign was associated with a significant reduction in MenC disease in children aged 0-4 years, yet no effect was observed in adolescents and adults, as evidenced by increasing trends in infection rates. In addition, the emergence of meningococcal serogroup A was identified, which should serve as an alert to public health officials and deserves further investigation.

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.

Estimation of the real burden of invasive meningococcal disease in Argentina

Among the different existing types of bacterial meningitis, the one caused by Neisseria meningitidis is the main presentation of invasive meningococcal disease (IMD). IMD is a significant public health concern and has a reported incidence rate in Argentina of 0.44 cases per 100 000 inhabitants in 2015. However, the actual incidence is thought to be higher as passive surveillance systems neither report nor identify 100% of all cases. The aim of this study is to develop an estimation of the burden of IMD in Argentina closer to reality by adjusting/correcting several limitations observed in the surveillance data available. A retrospective observational study has been performed using four Argentinean national databases recording the number of IMD cases and deaths, serogroups of N. meningitidis and ages, between 2007 to 2016. The reported data were adjusted to account for underreporting and to also integrate the cases missed due to well-known limitations associated with the diagnosis of N. meningitidis detection methods. Data were further analysed by serogroups of N. meningitidis and by age groups. After these adjustments, the potential numbers of IMD cases and IMD-related deaths are estimated to be 3.1 and 1.9 higher than reported, respectively. The study corrects the previous underestimation of the disease burden and provides expectedly more robust estimates aligned with international evidence and highlights the importance of active surveillance, with high-quality methods, for a better definition of preventive strategies against IMD in Argentina.

[Death within Hours]

Death within Hours Abstract. The clinical picture of invasive meningococcal disease is broad, it mostly manifests as meningitis and/or sepsis. The severity ranges from a simple bacteremia associated with mild, unspecific symptoms to fulminant sepsis with multiorgan failure and death, which happens in 10-15 % of cases. Sometimes purely local infections (e.g. septic arthritis or conjunctivitis) or rarely a chronic course (prolonged, intermittent fever, rash, arthritis and headache) are the only clinical manifestation - which can also lead to a disseminated fulminant disease. Our case illustrates the tragic progression of a fulminant meningococcal sepsis with rapid death.

Carriage prevalence of Neisseria meningitidis in the Americas in the 21st century: a systematic review

Neisseria meningitidis is a bacterium that colonizes the human nasopharynx and is transmitted by respiratory droplets from asymptomatic or symptomatic carriers. Occasionally, the pathogen invades the mucosa and enters the bloodstream, causing invasive meningococcal disease, a life-threatening infection. While meningococcal colonization is the first step in the development of invasive disease, the risk factors that predict progression from asymptomatic to symptomatic status are not well-known. The present report aimed to describe the prevalence of N. meningitidis carriers throughout the Americas, emphasizing the risk factors associated with carrier status, as well as the most prevalent serogroups in each studied population. We conducted a systematic review by searching for original studies in the MEDLINE/PubMed, Embase, LILACS and SciELO databases, published between 2001 and 2018. Exclusion criteria were articles published in a review format, case studies, case control studies, investigations involving animal models, and techniques or publications that did not address the prevalence of asymptomatic carriers in an American country. A total of 784 articles were identified, of which 23 were selected. The results indicate that the highest prevalence rates are concentrated in Cuba (31.9%), the United States (24%), and Brazil (21.5%), with increased prevalence found among adolescents and young adults, specifically university students and males. The present systematic review was designed to support epidemiological surveillance and prevention measures to aid in the formulation of strategies designed to control the transmission of meningococci in a variety of populations and countries throughout the Americas.

Molecular diagnosis of microbial copathogens with influenza A(H1N1)pdm09 in Oaxaca, Mexico

Background

Multiple factors have been associated with the severity of infection by influenza A(H1N1)pdm09. These include H1N1 cases with proven coinfections showing clinical association with bacterial contagions.

Purpose

The objective was to identify H1N1 and copathogens in the Oaxaca (Mexico) population. A cross-sectional survey was conducted from 2009 to 2012. A total of 88 study patients with confirmed H1N1 by quantitative RT-PCR were recruited.

Methods

Total nucleic acid from clinical samples of study patients was analyzed using a TessArray RPM-Flu microarray assay to identify other respiratory pathogens.

Results

High prevalence of copathogens (77.3%; 68 patients harbored one to three pathogens), predominantly from Streptococcus, Haemophilus, Neisseria, and Pseudomonas, were detected. Three patients (3.4%) had four or five respiratory copathogens, whereas others (19.3%) had no copathogens. Copathogenic occurrence with Staphylococcus aureus was 5.7%, Coxsackie virus 2.3%, Moraxella catarrhalis 1.1%, Klebsiella pneumoniae 1.1%, and parainfluenza virus 3 1.1%. The number of patients with copathogens was four times higher to those with H1N1 alone (80.68% and 19.32%, respectively). Four individuals (4.5%; two males, one female, and one infant) who died due to H1N1 were observed to have harbored such copathogens as Streptococcus, Staphylococcus, Haemophilus, and Neisseria.

Conclusion

In summary, copathogens were found in a significant number (>50%) of cases of influenza in Oaxaca. Timely detection of coinfections producing increased acuity or severity of disease and treatment of affected patients is urgently needed.

Four-year antibody persistence and response to a booster dose of a pentavalent MenABCWY vaccine administered to healthy adolescents and young adults

This open-label, multicenter extension study (NCT02451514) assessed persistence of Neisseria meningitidis serogroups ABCWY antibodies 4 years after primary vaccination. Adolescents and young adults who previously received 2 doses of MenABCWY+OMV (Group III), 1 dose of MenACWY-CRM (Group VI), or newly-recruited vaccine-naïve participants (Group VII) were administered 1 (Group III) or 2 doses (Groups VI and VII) of MenABCWY+OMV, 1 month apart. Immunogenicity was assessed by human serum bactericidal assay (hSBA). Safety and reactogenicity were also evaluated. Percentages of participants with hSBA titers ≥8 (serogroups ACWY), ≥5 (serogroup B) and hSBA geometric mean titers (GMTs) were evaluated in all 129 enrolled participants (Group III: 33; Group VI: 46; Group VII: 50). Anti-ACWY antibody concentrations waned over 4 years post-vaccination, but remained above pre-vaccination concentrations. Similarly, levels of antibodies against serogroup B test strains also waned over 4 years post-vaccination, but remained above pre-vaccination concentrations for some strains. MenABCWY+OMV booster induced a robust anamnestic anti-ACWY response in Group III and VI and a good response against serogroup B test strains (≥82%) in Group III. In serogroup B-naïve participants (Groups VI and VII), anti-B responses to 2 doses of MenABCWY+OMV were less homogenous and lower than in Group III. MenABCWY+OMV was reactogenic, but well-tolerated. No safety concerns were identified. These findings indicate that although antibodies against N. meningitidis serogroups ABCWY waned over 4 years post-vaccination, exposure to a MenABCWY+OMV booster dose elicits an anamnestic response in adolescents previously exposed to the same or another multivalent meningococcal vaccine.

Prevalence and genetic characteristics of 4CMenB and rLP2086 vaccine candidates among Neisseria meningitidis serogroup B strains, China

OBJECTIVE

To systematically investigate the prevalence and genetic characteristics of 4CMenB and rLP2086 vaccine candidates among Neisseria meningitidis serogroup B (NmB) in China.

METHODS

A total of 485 NmB strains isolated in 29 provinces of China between 1968 and 2016 were selected from the culture collection of the national reference laboratory according to the isolation year, location, and source. Multi-locus sequence typing (MLST) and porA gene sequencing were performed on all 485 study strains; PCR was used to detect the fHbp, nadA, and nhba gene of 432 strains; positive amplification products from the fHbp and nadA genes from all strains, as well as those of the nhba gene from 172 representative strains, were sequenced.

RESULTS

MLST results showed that the predominant (putative) clonal complexes (CCs) of NmB isolates have changed over time in China. While strains that could not be assigned to existing (p)CCs were the biggest proportion, CC4821 was the most prevalent lineage (36.0%) since 2005. PCR and sequence analysis revealed that the 4CMenB and rLP2086 vaccine candidates were highly diverse. Respectively, 152 PorA genotypes and 83 VR2 sequences were identified with significant diversity within a single CC; the complete nadA gene was found in ten of 432 study strains; fHbp was present in most strains (422/432) with variant 2 predominating (82.9%) in both patient- and carrier- derived isolates; almost all strains harbored the nhba gene while sequences were diverse.

CONCLUSIONS

With regards to clonal lineages and vaccine candidate proteins, NmB isolates from China were generally diverse. Further studies should be performed to evaluate the cross-protection of present vaccines against Chinese NmB strains.

Challenges and opportunities for meningococcal vaccination in the developing world

Meningococcal disease continues to be a life threatening infection with high morbidity and mortality even in appropriately treated patients. Meningococcal vaccination plays a major role in the control of the disease; however, implementing vaccination remains problematic in the developing world. The objective of this review is to identify the challenges facing the use of meningococcal vaccines in the developing world in order to discuss the opportunities and available solutions to improve immunization in these countries. Inadequate epidemiologic information necessary to implement vaccination and financial challenges predominate. Multiple measures are needed to achieve the successful implementation of meningococcal conjugate vaccination programs that protect against circulating serogroups in developing countries including enhanced surveillance systems, financial support and aid through grants, product development partnerships that are the end result of effective collaboration and communication between different interdependent stakeholders to develop affordable vaccines, and demonstration of the cost-effectiveness of new meningococcal vaccines.

Impact of meningococcal C conjugate vaccination programs with and without catch-up campaigns in adolescents: Lessons learned from Bahia, Brazil

The significant increase in the incidence rates and ongoing outbreaks of serogroup C meningococcal (MenC) disease, associated with the sequence type-103 complex, motivated the incorporation of the meningococcal C conjugate (MCC) vaccine in the routine immunization program in the State of Bahia, Brazil in early 2010, targeting children younger than 5 years of age. In its capital, Salvador, the program also included a catch-up campaign for individuals 10-24 years of age. We performed an observational, ecological study, analyzing data collected from 2007 to 2015, to compare the impact of these two immunization strategies on meningococcal disease incidence and mortality rates. In Salvador, following the vaccination program, a dramatic early impact on MenC disease and mortality rates could be observed, with significant reductions in incidence rates of MenC disease in all age groups, including individuals that were too old to have been vaccinated, indicating the presence of herd protection. Compared to the pre-vaccine period, a virtual disappearance of MenC disease was observed in 2015. However, in the state of Bahia (excluding the city of Salvador), no herd protection could be observed, with significant impact only among vaccine-eligible children within 5 years of introduction of the MCC vaccination program. These results highlight the importance of catch-up campaigns, including adolescents and young adults, to induce herd protection compared to immunization strategies restricted to infants and young children. This information is crucial for identifying optimal immunization policies and future strategies, focused on adolescents, to optimize the impact of MCC vaccination programs.

Meningococcal disease, a clinical and epidemiological review

Meningococcal disease is the acute infection caused by Neisseria meningitidis, which has humans as the only natural host. The disease is widespread around the globe and is known for its epidemical potential and high rates of lethality and morbidity. The highest number of cases of the disease is registered in the semi-arid regions of sub-Saharan Africa. In Brazil, it is endemic with occasional outbreaks, epidemics and sporadic cases occurring throughout the year, especially in the winter. The major epidemics of the disease occurred in Brazil in the 70's caused by serogroups A and C. Serogroups B, C and Y represent the majority of cases in Europe, the Americas and Australia. However, there has been a growing increase in serogroup W in some areas. The pathogen transmission happens for respiratory route (droplets) and clinically can lead to meningitis and sepsis (meningococcemia). The treatment is made with antimicrobial and supportive care. For successful prevention, we have some measures like vaccination, chemoprophylaxis and droplets' precautions. In this review, we have described and clarify clinical features of the disease caused by N. meningitidis regarding its relevance for healthcare professionals.

Capsule switching of Neisseria meningitidis sequence type 7 serogroup A to serogroup X

OBJECTIVES

The bacterial pathogen Neisseria meningitidis is able to escape the currently available capsule-based vaccines by undergoing capsule switching. In this study, we investigated whether capsule switching has occurred in a recently emerged sequence type (ST) 7 serogroup X isolate in China, for which currently no vaccine is available.

METHODS

To identify capsule switching breakpoints, the capsule locus and flanking regions of the ST-7 serogroup X isolate and three endemic ST-7 serogroup A isolates were sequenced and compared. To obtain further insight into capsule switching frequency and length of DNA fragments involved, capsule switching assays were performed using genomic DNA containing combinations of antibiotic selection markers at various locations in the capsule locus and flanking regions.

RESULTS

Sequence analyses showed that capsule switching has occurred and involved a 8450 bp serogroup X DNA fragment spanning the region from galE to ctrC. Capsule switching assays indicate that capsule switching occurs at a frequency of 6.3 × 10^-6 per bacterium per μg of DNA and predominantly involved DNA fragments of about 8.1-9.6 kb in length.

CONCLUSIONS

Our results show that capsule switching in N. meningitidis occurs at high frequency and involves recombination in the flanking regions of the capsule biosynthesis genes.

A cross-sectional study assessing the pharyngeal carriage of Neisseria meningitidis in subjects aged 1-24 years in the city of Embu das Artes, São Paulo, Brazil

Meningococcal carriage is a prerequisite for invasive infection. This cross-sectional study assessed the pharyngeal carriage prevalence in healthy subjects aged 1-24 years in Embu das Artes city, São Paulo, Brazil. Pharyngeal swabs were examined for the presence of Neisseria meningitidis. The isolates were tested for different serogroups using agglutination and polymerase chain reaction. A logistic regression model assessed any independent association between Neisseria meningitidis carriage and various risk factors. A total of 87/967 subjects (9%, 95% Confidence Interval (CI): 7.3-11.0) tested positive for N. meningitidis: 6.2% (95% CI: 3.8-9.4) in 1-4 years, 8.5% (95% CI: 5.1-13.0) in 5-9 years, 12.5% (95% CI: 7.8-18.6) in 10-14 years, 12.6% (95% CI: 7.4-19.7) in 15-19 years and 9% (95% CI: 4.9-14.9) in 20-24 years age groups. Highest carriage prevalence was observed in adolescents 10-19 years old. Serogroup C was predominant (18.4%) followed by serogroup B (12.6%). The 15-19 years age group showed a significant association between number of household members and carriers of N. meningitidis. This cross-sectional study is the first in Brazil to evaluate meningococcal carriage prevalence and associated factors in a wide age range.

Burden of Neisseria meningitidis infections in China: a systematic review and meta-analysis

BACKGROUND

Neisseria meningitidis is a leading cause of bacterial meningitis and septicemia in children and young adults worldwide. The disease burden associated with N. meningitidis infections has not been systematically assessed in China. Therefore, we undertook this study to determine the burden of meningococcal disease in China.

METHOD

We performed a systematic review and meta-analysis of articles on N. meningitidis incidence, carriage, seroprevalence and mortality rates in China by searching the Chinese BioMedical Database (CBM), China National Knowledge Infrastructure (CNKI), Wanfang database and PubMed for publications from January 2005 to Aug 2015.

RESULTS

In total, 50 articles were included in our analysis. The overall incidence of meningococcal disease and associated mortality were estimated to be 1.84 (95% confidence interval (CI) 0.91-3.37) per 100 000 persons per year and 0.33 (95% CI 0.12-0.86) per 100 000 persons per year, respectively. N. meningitidis carriage rate among the healthy population was estimated to be 2.7% (95% CI 2.0-3.5%). Prevalence of antibodies against N. meningitidis serogroup A and C were estimated to be 77.3% (95% CI 72.4%-81.6%) and 33.5% (95% CI 27.0%-40.8%), respectively. No studies were found for serogroup specific disease burden.

CONCLUSIONS

The overall incidence of meningococcal disease in China is low. The lower seroprevalence of serogroup C within the population suggests that it may pose a greater risk for meningococcal disease outbreak than serogroup A. The lack of data on serogroup disease burden by age groups suggests the implementation of laboratory based meningococcal surveillance systems are urgently needed in China.

Meningococcal Disease in Children in Argentina A 3-year Active Sentinel Hospital Surveillance Study

BACKGROUND

Meningococcal disease (MD) is a medical emergency and a serious public health problem. As new meningococcal vaccines become available, MD surveillance is crucial to provide baseline epidemiologic data before implementing preventive measures. We estimated MD incidence and epidemiology in Argentina using hospital-based surveillance.

METHODS

Three-year prospective active surveillance in patients ≤15 years of age was conducted at 6 pediatric hospital sentinel units (March 2012 to February 2015).

RESULTS

Of 184,360 hospitalized patients, 1444 (0.78%) had suspected meningitis or MD. Of these, 268 (19%) presented probable acute bacterial meningitis or MD, 168 (63%) were culture positive and 51 (30%) tested positive for Neisseria meningitidis. Of 100 culture-negative cases, 30 had positive meningococcal polymerase chain reaction. Thirteen patients presented other uncommon MD manifestations, resulting in a total of 94 MD cases and an annual incidence of 5.1/10 hospitalized patients [95% confidence interval (CI): 4-6]. Fifty-four (57%) patients were males, 48% were <1 year of age and the median age was 12.5 months (1 month to 15 years). Clinical presentations were the following: meningococcemia and meningitis (37%), meningitis (30%), meningococcemia (16%), arthritis (10%), bacteremia (5%) and pneumonia (2%). Twenty-eight percent had complications. Nine children died (case fatality rate: 10%), and 8 had sequelae. Serogroups were identified for 84 isolates. Serogroup W was associated with age <1 year (odds ratio: 3.18; 95% CI: 1.14-8.99); meningococcemia was associated with mortality (P = 0.0038).

CONCLUSIONS

Highest rates of MD were observed among young infants. This study provides baseline data to estimate the impact of introducing meningococcal vaccines in Argentina.

Control of invasive meningococcal disease: is it achievable?

Neisseria meningitidis still leads to deaths and severe disability in children, adolescents and adults. Six different capsular groups of N. meningitidis cause invasive meningococcal disease in the form of meningitis and septicaemia in humans. Although conjugate meningococcal vaccines have been developed to provide protection against four of the capsular groups causing most diseases in humans, vaccines against capsular group B, which causes 85% of cases in Australia and the United Kingdom, have only recently been developed. A capsular group B meningococcal vaccine - 4CMenB (Bexsero) - has recently been licensed in the European Union, Canada and Australia. In Australia, a submission for inclusion of 4CMenB in the funded national immunization programme has recently been rejected. The vaccine will now be introduced into the national immunization programme in the United Kingdom following negotiation of a cost-effective price. With the current low incidence of invasive meningococcal disease in many regions, cost-effectiveness of a new capsular group B meningococcal vaccine is borderline in both the United Kingdom and Australia. Cost-effectiveness of an infant programme is determined largely by the direct protection of those vaccinated and is driven by the higher rate of disease in this age group. However, for an adolescent programme to be cost-effective, it must provide both long-term protection against both disease and carriage. The potential of vaccination to reduce the rate of severe invasive disease is a real possibility. A dual approach using both an infant and adolescent immunization programme to provide direct protection to those age groups at highest risk of meningococcal disease and to optimize the potential herd immunity effects is likely to be the most effective means of reducing invasive meningococcal disease. This commentary aims to describe the known disease burden and consequences of meningococcal disease, and the development and potential effectiveness of new capsular group B meningococcal vaccines.

Association of serum bactericidal antibody and opsonic antibody levels after Neisseria meningitidis serogroup C conjugate vaccine in Brazilian children and adolescents infected or not infected with HIV

Neisseria meningitidis serogroup C (MenC) is the main causative agent of meningitis in Brazil. HIV infection affects the quality of the immune system. HIV⁺ children have an increased risk of infection to encapsulated bacteria such as N. meningitidis. We evaluated the opsonic antibody (OPA) levels and its correlation with serum bactericidal antibody (SBA) levels induced by one and two doses of a MenC conjugate vaccine in children and adolescents HIV⁺ and HIV-exposed but uninfected children (HEU) group. Overall the data show the importance of two doses of vaccine for HIV⁺ individuals. About 79% and 58% of HIV⁺ patients showed SBA and OPA positive response after two doses of vaccine, respectively. For HEU group, 62% and 41% of patients showed SBA and OPA positive response after one dose of vaccine, respectively. A positive and significant association between SBA and OPA levels was seen after two doses of vaccine in HIV⁺ patients.

Meningococcal meningitis: clinical and laboratorial characteristics, fatality rate and variables associated with in-hospital mortality

ABSTRACT Meningococcal meningitis is a public health problem. The aim of this study was to describe the clinical characteristics of patients with meningococcal meningitis, and to identify associated factors with mortality. This was a retrospective study, between 2006 and 2011, at a referral center in São Paulo, Brazil. Logistic regression analysis was used to identify factors associated with mortality. We included 316 patients. The median age was 16 years (IQR: 7–27) and 60% were male. The clinical triad: fever, headache and neck stiffness was observed in 89% of the patients. The cerebrospinal triad: pleocytosis, elevated protein levels and low glucose levels was present in 79% of patients. Factors associated with mortality in the multivariate model were age above 50 years, seizures, tachycardia, hypotension and neck stiffness. The classic clinical and laboratory triads of meningococcal meningitis were variable. The fatality rate was low. Age, seizures and shock signs were independently associated with mortality.

Cobertura da vacina meningocócica C nos estados e regiões do Brasil em 2012

Objetivos: Descrever a cobertura da vacina meningocócica C em crianças menores de um ano de idade, em 2012, nos estados e regiões do Brasil, e correlacionar com variáveis socioeconômicas e cobertura da Estratégia de Saúde da Família. Métodos: Estudo ecológico. A cobertura vacinal foi calculada utilizando o número de doses da vacina em 2012, disponível no Sistema de Informação do Programa Nacional de Imunizações, como numerador, e população residente menor de um ano, também em 2012, como denominador. Ainda, foi realizada uma correlação de Pearson (r) entre a cobertura vacinal e as variáveis socioeconômicas. Resultados: As regiões Norte e Nordeste não atingiram a recomendação de 95% para cobertura. A cobertura vacinal apresentou correlação positiva moderada com renda média per capita (r=0,6) e negativa e moderada com o coeficiente de Gini (r=-0,5). Conclusão: São necessárias ações educativas e políticas para aumentar a cobertura vacinal com objetivo de reduzir a incidência da doença meningocócica, além de estudos com delineamentos mais robustos.

Meningococcal quadrivalent tetanus toxoid conjugate vaccine (MenACWY-TT, Nimenrix™): A review of its immunogenicity, safety, co-administration, and antibody persistence

INTRODUCTION

Meningococcal disease is a major cause of morbidity and mortality worldwide with reported epidemics and outbreaks in different parts of the world. Despite the availability of antimicrobial therapy, challenges remain in early recognition and prevention of disease. Several vaccines have been developed to date aiming at preventing disease spread.

DISCUSSION

MenACWY-TT (Nimenrix™) has been extensively studied for use in different age groups. Phase II and III randomized trials have demonstrated its immunogenicity when administered in children aged 1 year and older, adolescents and adults. It has an acceptable safety profile with minor adverse events comparable to other vaccines. Follow up studies have shown persistence of protective antibodies up to three years. MenACWY-TT was safely and effectively co-administered with different recommended vaccines.

CONCLUSION

MenACWY-TT is a safe and immunogenic vaccine that can be used to protect against these four serogroups in individuals older than 1 year of age.

Cost-effectiveness analysis of a multicomponent meningococcal serogroup B vaccine in hypothetic epidemic situation in a middle-income country

NmenB vaccine (4CMenB) is now available, but studies on the cost-effectiveness of vaccine introduction in a country outbreak situation are lacking. The aim of this study was to evaluate the cost-effectiveness of 4CMenB in the context of a hypothetical epidemic outbreak in Chile. We analyzed the direct and indirect costs of acute disease, sequelae and death for each case of meningococcal disease (MD) based on information obtained during the latest NmenB outbreak in Santiago, Chile, occurring between 1993-1999, with an incidence of 5.9/100,000 inhabitants and a mortality of 7.3%. We analyzed the cost of a mass vaccination campaign, considering one dose of 4CMenB for population between 12 months and 25 y of age and 3 doses for infants. Cost-effectiveness analysis was based on 80% and 92% 4CMenB immunogenicity for individual's bellow and over 12 months respectively. Sensitivity analysis was applied to different vaccine costs.

RESULTS

The total cost of the epidemic was USD $59,967,351, considering individual cost of each acute case (USD$2,685), sequelae (USD$2,374) and death (USD $408,086). In Chile, the 4CMenB mass vaccination strategy would avoid 215 cases, 61 sequelae, and 16 deaths per year. The strategy would be cost-effective at a vaccine dose cost ≤ of USD$18.

CONCLUSIONS

Implementation of a mass vaccination campaign to control a hypothetical NmenB outbreak in Chile would be cost-effective at a vaccine cost per dose ≤ of USD$18. This is the first report of a cost-effectiveness analysis for use of 4CMenB as a single intervention strategy to control an epidemic outbreak of NmenB.

Neisseria meningitidis and Streptococcus pneumoniae as leading causes of pediatric bacterial meningitis in nine Mexican hospitals following 3 years of active surveillance

OBJECTIVES

Meningococcal meningitis is reported as a rare condition in Mexico. There are no internationally published studies on bacterial causes of meningitis in the country based on active surveillance. This study focuses on finding the etiology of bacterial meningitis in children from nine Mexican Hospitals.

METHODS

From January 2010 to February 2013, we conducted a three years of active surveillance for meningitis in nine hospitals throughout Mexico. Active surveillance started at the emergency department for every suspected case, and microbiological studies confirmed/ruled out all potentially bacterial pathogens. We diagnosed based on routine cultures from blood and cerebrospinal fluid (not polymerase chain reaction or other molecular diagnostic tests), and both pneumococcal serotyping and meningococcal serogrouping by using standard methods.

RESULTS

Neisseria meningitidis was the leading cause, although 75% of cases occurred in the northwest of the country in Tijuana on the US border. Serogroup C was predominant. Streptococcus pneumoniae followed Neisseria meningitides, but was uniformly distributed throughout the country. Serotype 19A was the most incident but before universal implementation of the 13-valent pneumococcal conjugate vaccine. Other bacteria were much less common, including Enterobacteriaceae and Streptococcus agalactiae (these two affecting mostly young infants).

CONCLUSIONS

Meningococcal meningitis is endemic in Tijuana, Mexico, and vaccination should be seriously considered in that region. Continuous universal vaccination with the 13-valent pneumococcal conjugate vaccine should be nationally performed, and polymerase chain reaction should be included for bacterial detection in all cultures - negative but presumably bacterial meningitis cases.

Immune responses to a recombinant, four-component, meningococcal serogroup B vaccine (4CMenB) in adolescents: a phase III, randomized, multicentre, lot-to-lot consistency study

BACKGROUND

For decades, a broadly effective vaccine against serogroup B Neisseria meningitidis (MenB) has remained elusive. Recently, a four-component recombinant vaccine (4CMenB) has been developed and is now approved in Europe, Canada, Australia and some Latin American countries. This phase III, randomized study evaluated the lot consistency, early immune responses and the safety profile of 4CMenB in 11 to 17-year-old adolescents in Australia and Canada (NCT01423084).

METHODS

In total, 344 adolescents received two doses of one of 2 lots of 4CMenB, 1-month apart. Immunogenicity was assessed before, 2-weeks and 1-month following the second vaccination. Serum bactericidal activity using human complement (hSBA) was measured against three reference strains 44/76-SL, 5/99 and NZ98/254, selected to express one of the vaccine antigens; Neisseria adhesin A (NadA), factor H binding protein (fHbp) and porin A (PorA) containing outer membrane vesicle (OMV), respectively. Responses to the Neisseria heparin binding antigen (NHBA) were assessed with enzyme linked immunosorbent assay (ELISA). Local and systemic reactions were recorded for 7 days following each vaccination; unsolicited adverse events were monitored throughout the study.

RESULTS

Immunological equivalence of the two lots of 4CMenB was established at 1-month. At baseline, ≤7% of participants had hSBA titers ≥5 to all three reference strains. Two weeks following the second dose of 4CMenB, all participants had hSBA titers ≥5 against fHbp and NadA compared with 84-96% against the PorA reference strains. At 1-month, corresponding proportions were 99%, 100% and 70-79%, respectively. Both lots were generally well tolerated and had similar adverse event profiles.

CONCLUSIONS

Two doses of 4CMenB had an acceptable safety profile and induced a robust immune response in adolescents. Peak antibody responses were observed at 14 days following vaccination. While a substantial non-uniform antigen-dependent early decline in antibody titers was seen thereafter, a significant percentage of participants continued to maintain protective hSBA titers at 1-month.

Meningococcal disease before and after the introduction of meningococcal serogroup C conjugate vaccine. Federal District, Brazil

Objectives

To analyze the behavior of meningococcal disease in the Federal District, Brazil, from 2005 to 2011, and to assess the direct impact of the meningococcal serogroup C conjugate vaccine.

Methods

A descriptive study of cases of meningococcal disease among residents of the Federal District. We included in the study confirmed cases of meningococcal disease reported to the local surveillance. To reduce underreporting we compared data to the Brazilian Mortality Database and the Public Health Laboratory Database. We studied sociodemographic, clinical, and pathogen-related variables. For the assessment of the impact of meningococcal serogroup C conjugate vaccine, which was introduced in 2010 for children under two years of age, we compared the incidence of meningococcal disease before and after vaccine introduction in the recommended age groups for vaccination.

Results

We identified 309 cases of meningococcal disease, of which 52.1% were males. The average case fatality rate was 20.7%, the median age was three years and there was a predominance of serogroup C (70.2%) and C:23:P1.14-6 phenotype throughout the study period. In 2005–2009, 2010 and 2011, the incidence rates of meningococcal disease were 2.0, 1.8 and 0.8/100,000 inhabitants/year, while mortality rates were 0.4, 0.4 and 0.2/100,000 inhabitants/year, respectively. In the first and last periods, the incidence in poorer and more affluent areas were, respectively, 2.0 and 0.8, and 0.9 and 0.0/100,000 inhabitants/year. Comparing 2009 (the year prior to the introduction of meningococcal serogroup C conjugate vaccine) and 2011, there was 85% reduction in the incidence of serogroup C meningococcal disease in children under four years of age, from 9.0 to 1.3/100,000 (p < 0.01).

Conclusions

The meningococcal serogroup C conjugate vaccine strategy implemented in Brazil proved highly effective and had a strong direct impact on the target population. However, case fatality rates of meningococcal disease remain high with a wide gap in the risk of disease between poor and affluent areas, pointing to the need to reexamine the current strategy on a regular base.

An outbreak of serogroup C (ST-11) meningococcal disease in Tijuana, Mexico

BACKGROUND

Invasive meningococcal disease (IMD) has been reported to be endemic in children from Tijuana, Mexico and the risk of an outbreak was always a threat.

OBJECTIVES

To describe all clinical, epidemiological and microbiological features of a meningococcal outbreak that occurred in Tijuana, Mexico.

METHODS

All cases with IMD were admitted at different emergency departments within the city and diagnosed by culture and agglutination tests. Further restriction fragment length polymorphism pulse field gel electrophoresis (RFLP-PFGE) and multi locus sequence typing (MLST) were performed. All clinical and epidemiological characteristics and interventions were evaluated, as well as risk factors associated with mortality.

RESULTS

From 30 January 2013 to 30 March 2013 there were 19 cases of IMD all caused by Neisseria meningitidis serogroup C. The median age was 16 years (2-47), with higher frequency among individuals at least 13 years old (73.7%). At admission, meningitis was the main clinical presentation (94.7%), followed by purpura (78.9%), septic shock (42.1%) and disseminated intravascular coagulation (DIC, 36.8%). Overall mortality was seven (36.8%). Variables associated with higher mortality were, at admission, presence of septic shock, DIC and thrombocytopenia less than 70,000. All 19 cases had no identifiable site or cluster as the source of the outbreak. RFLP-PFGE showed a discriminatory power for only one profile on all N. meningitidis strains analyzed and a clone ST-11 was identified in all strains. Public health interventions were continuous case reporting of all suspected cases of IMD, an increase in active surveillance in all hospitals, training of medical and laboratory personnel, massive and rapid chemoprophylaxis to all close contacts as indicated, and promotion of good health habits.

CONCLUSIONS

An outbreak with high mortality of IMD occurred in Tijuana, Mexico. This event and evidence of endemicity should encourage health authorities to evaluate meningococcal vaccination in the region.

A consensus statement: meningococcal disease among infants, children and adolescents in Latin America

Invasive meningococcal disease is a serious infection that occurs worldwide. Neisseria meningitidis remains one of the leading causes of bacterial meningitis in all ages. Despite the availability of safe and effective vaccines against invasive meningococcal disease, few countries in Latin America implemented routine immunization programs with these vaccines. The Americas Health Foundation along with Fighting Infectious Disease in Emerging Countries recently sponsored a consensus conference. Six experts in infectious diseases from across the region addressed questions related to this topic and formulated the following recommendations: (1) standardized passive and active surveillance systems should be developed and carriage studies are mandatory; (2) a better understanding of the incidence, case fatality rates and prevalent serogroups in Latin America is needed; (3) countries should make greater use of the polymerase chain reaction assays to improve the sensitivity of diagnosis and surveillance of invasive meningococcal disease; (4) vaccines with broader coverage and more immunogenicity are desirable in young infants; (5) prevention strategies should include immunization of young infants and catch-up children and adolescents and (6) because of the crowded infant immunization schedule, the development of combined meningococcal vaccines and the coadministration with other infant vaccines should be explored.

An epidemiological review of changes in meningococcal biology during the last 100 years

AIM

The aim of this study was to assess changes in trends of meningococcal disease and strain diversity of Neisseria meningitidis in Europe, South America, and Africa over the last 100 years.

METHODS

Healthcare databases and sources of grey literature were searched in 2012 and records were screened against the protocol eligibility criteria using a three-stage sifting process. Studies included in the review were subject to data extraction. Results were summarised using a narrative approach.

RESULTS

Serogroup A was the dominant cause of invasive meningococcal disease in Europe before and during World Wars I and II. Whilst serogroup B has been dominant from the 1970s in Europe and the 1980s in South America, outbreaks have emerged associated with serogroups W135 and Y in the twenty-first century. There has been a shift in the age groups affected by invasive meningococcal disease with an increase in incidence among the elderly associated with serogroup Y and a decline in serogroup C among adolescent populations. Recent outbreaks of serogroup W135 have occurred in some countries in South America. The epidemiological trend of invasive meningococcal disease has remained largely static across Africa and dominated by serogroup A although recently serogroups X and W135 have accounted for a large proportion of morbidity and mortality.

CONCLUSION

The epidemiology of N. meningitidis has been dynamic in Europe and South America especially over the last 30 years. Routine vaccination with serogroup C vaccines has led to reduced carriage and incidence of invasive meningococcal disease and herd immunity.

Global epidemiology of invasive meningococcal disease

Neisseria meningitidis is one of the leading causes of bacterial meningitis globally and can also cause sepsis, pneumonia, and other manifestations. In countries with high endemic rates, the disease burden places an immense strain on the public health system. The worldwide epidemiology of invasive meningococcal disease (IMD) varies markedly by region and over time. This review summarizes the burden of IMD in different countries and identifies the highest-incidence countries where routine preventive programs against Neisseria meningitidis would be most beneficial in providing protection. Available epidemiological data from the past 20 years in World Health Organization and European Centre for Disease Prevention and Control collections and published articles are included in this review, as well as direct communications with leading experts in the field. Countries were grouped into high-, moderate-, and low-incidence countries. The majority of countries in the high-incidence group are found in the African meningitis belt; many moderate-incidence countries are found in the European and African regions, and Australia, while low-incidence countries include many from Europe and the Americas. Priority countries for vaccine intervention are high- and moderate-incidence countries where vaccine-preventable serogroups predominate. Epidemiological data on burden of IMD are needed in countries where this is not known, particularly in South- East Asia and Eastern Mediterranean regions, so evidence-based decisions about the use of meningococcal vaccines can be made.

Invasive meningococcal disease

Invasive meningococcal disease (IMD) is a major public health and continues to cause substantial mortality and morbidity. Serotype C is the most frequent in Brazil. The clinical spectrum of IMD is broad (meningitis, meningococcemia or both) and the clinical evolution may be unpredictable. Main features associated with mortality are: age higher than 50 years old, seizures, shock, and meningococcemia without meningitis. Blood cultures should be obtained immediately. Lumbar puncture can be performed without previous computed tomography scan (CT) in most cases. Clinical features can be useful to predic patients where an abnormal CT scan is likely. Cerebrospinal fluid (CSF) culture and Gram stain should always be required. Latex agglutination sensitivity is highly variable. Polymerase chain reaction is specially useful when other methods are negative or delayed. Usually ceftriaxone should not be delayed while awaiting CSF study or CT. Dexamethasone can be used in meningococcal meningitis. Early suspicion of IMD and antibiotic in primary care before hospitalization, rapid transportation to a hospital, and stabilization in an intensive-care unit has substantially reduced the case-fatality rate. Vaccines against serotypes A, C, W-135, and Y are available while vaccines against serotype B are expected.

The current situation of meningococcal disease in Latin America and recommendations for a new case definition from the Global Meningococcal Initiative

The Global Meningococcal Initiative (GMI) is an international group of scientists and clinicians with expertise in meningococcal disease (MD). It promotes MD prevention through education and research. Given geographic differences in disease epidemiology, prevention strategies (e.g., vaccination) should be country-specific to ensure local needs are met. However, regional policies/recommendations and standardized disease diagnostic criteria should be implemented to improve surveillance and control strategies, and allow for more robust data comparisons. Consequently, the GMI convened a meeting with Latin American representatives to discuss the burden of MD and vaccination practices/policies, and consider if the global GMI recommendations could be tailored. The group determined that as robust, uniform epidemiologic data are required to make informed health-policy decisions, it would be useful to first summarize the regional situation herein (including disease surveillance, case definitions, epidemiology, vaccination and outbreak control strategies) and then determine a consensus-based meningococcal case definition for use throughout the region.

Cerebrospinal-fluid cytokine and chemokine profile in patients with pneumococcal and meningococcal meningitis

Background

Bacterial meningitis is characterized by an intense inflammatory reaction contributing to neuronal damage. The aim of this study was to obtain a comparative analysis of cytokines and chemokines in patients with pneumococcal (PM) and meningococcal meningitis (MM) considering that a clear difference between the immune response induced by these pathogens remains unclear.

Methods

The cyto/chemokines, IL-1β, IL-2, IL-6, TNF-α, IFN-γ, IL-10, IL-1Ra, CXCL8/IL-8, CCL2/MCP-1, CLL3/MIP-1α, CCL4/MIP-1γ and G-CSF, were measured in cerebrospinal fluid (CSF) samples from patients with PM and MM. Additionally, a literature review about the expression of cytokines in CSF samples of patients with MB was made.

Results

Concerning cytokines levels, only IFN-γ was significantly higher in patients with Streptococcus pneumoniae compared to those with Neisseria meningitidis, regardless of the time when the lumbar puncture (LP) was made. Furthermore, when samples were compared considering the timing of the LP, higher levels of TNF-α (P <0.05) were observed in MM patients whose LP was made within 48 h from the initial symptoms of disease. We also observed that the index of release of cyto/chemokines per cell was significantly higher in PM. From the literature review, it was observed that TNF-α, IL-1β and IL-6 are the best studied cytokines, while reports describing the concentration of the cytokine IL-2, IL-1Ra, G-CSF and CCL4/MIP-1β in CSF samples of patients with bacterial meningitis were not found.

Conclusion

The data obtained in this study and the previously published data show a similar profile of cytokine expression during PM and MM. Nevertheless, the high levels of IFN-γ and the ability to release high levels of cytokines with a low number of cells are important factors to be considered in the pathogenesis of PM and thereby should be further investigated. Moreover, differences in the early response induced by the pathogens were observed. However, the differences observed are not sufficient to trigger changes in the current therapy of corticosteroids adopted in both the PM and MM.

Treatment of bacterial meningitis: an update

INTRODUCTION

The introduction of protein conjugate vaccines for Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (S. pneumoniae) and Neisseria meningitidis (N. menigitidis) has changed the epidemiology of bacterial meningitis. Bacterial meningitis continues to be an important cause of mortality and morbidity, and our incomplete knowledge of its pathogenesis and emergence of antimicrobial resistant bacteria contribute to such mortality and morbidity. An early empiric antibiotic treatment is critical for the management of patients with bacterial meningitis.

AREAS COVERED

This article gives an overview on optimal treatment strategies of bacterial meningitis, along with considerations of new insights on epidemiology, clinical and laboratory findings supportive of bacterial meningitis, chemoprophylaxis, selection of initial antimicrobial agents for suspected bacterial meningitis, antimicrobial resistance and utility of new antibiotics, status on anti-inflammatory agents and adjunctive therapy, and pathogenesis of bacterial meningitis.

EXPERT OPINION

Prompt treatment of bacterial meningitis with an appropriate antibiotic is essential. Optimal antimicrobial treatment of bacterial meningitis requires bactericidal agents able to penetrate the blood-brain barrier (BBB), with efficacy in cerebrospinal fluid (CSF). Several new antibiotics have been introduced for the treatment of meningitis caused by resistant bacteria, but their use in human studies has been limited. More complete understanding of the microbial and host interactions that are involved in the pathogenesis of bacterial meningitis and associated neurologic sequelae is likely to help in developing new strategies for the prevention and therapy of bacterial meningitis.

Can we defeat meningococcal disease in low and middle income countries?

The development of multivalent conjugate and protein-based meningococcal vaccines may make global control of meningococcal disease possible. However, achieving control of meningococcal disease in low and middle income countries will be challenging. In low income countries whose vaccination programmes receive financial support from the Global Alliance for Vaccination and Immunisation, the main challenge is lack of sufficient epidemiological information to allow rational decisions on vaccine introduction to be made and, in these countries, enhanced surveillance is needed. In middle income countries, financial challenges predominate. These could be met by demonstration of the cost effectiveness of new meningococcal vaccines and through the introduction of a tiered-pricing system.

Future challenges in the elimination of bacterial meningitis

Despite the widespread implementation of several effective vaccines over the past few decades, bacterial meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis and Group B Streptococcus (GBS) still results in unacceptably high levels of human mortality and morbidity. A residual disease burden due to bacterial meningitis is also apparent due to a number of persistent or emerging pathogens, including Mycobacterium tuberculosis, Escherichia coli, Staphylococcus aureus, Salmonella spp. and Streptococcus suis. Here, we review the current status of bacterial meningitis caused by these pathogens, highlighting how past and present vaccination programs have attempted to counter these pathogens. We discuss how improved pathogen surveillance, implementation of current vaccines, and development of novel vaccines may be expected to further reduce bacterial meningitis and related diseases in the future.

Laboratory-based surveillance of Neisseria meningitidis isolates from disease cases in Latin American and Caribbean countries, SIREVA II 2006-2010

BACKGROUND

Published data on the epidemiology of meningococcal disease in Latin America and the Caribbean region is scarce and, when available, it is often published in Spanish and/or in non-peer-reviewed journals, making it difficult for the international scientific community to have access.

METHODS

Laboratory data on 4,735 Neisseria meningitidis strains was collected and reported by the National Reference Laboratories in 19 Latin American countries and the Caribbean Epidemiology Centre (CAREC) between 2006 and 2010 as part of the work carried out by the SIREVA II network. Serogroup and MIC to penicillin, rifampin and chloramphenicol were determined.

RESULTS

Isolates were mainly obtained from patients <5 years, but each year around 25% of isolates came from adult patients. Serogroup distribution was highly variable among countries. Serogroup C was the main cause of disease in Brazil; the majority of disease seen in the Southern cone was caused by serogroup B, but serogroup W135 strains have increased in recent years. In the Andean and Mexico, Central America and Caribbean regions, serogroups B and C were equally present, and serogroup Y was frequently isolated. Isolates were generally susceptible to chloramphenicol, penicillin and rifampin, but almost 60% of isolates characterized in Southern cone countries presented intermediate resistance to penicillin. Five rifampin-resistant isolates have been isolated in Uruguay and Brazil.

CONCLUSIONS

Serogroup distribution is highly variable among countries, but some geographic structuring can be inferred from these data. Epidemiological and laboratory data are scarce among Andean and Mexico, Central America and Caribbean countries. Evaluation and implementation of corrective measures on disease surveillance and reporting systems and the implementation of molecular diagnostic techniques and molecular characterization on meningococcal isolates are advised.

The epidemiology of meningococcal disease in Latin America 1945-2010: an unpredictable and changing landscape

Meningococcal disease is mostly endemic in Latin America, with periodic occurrences of outbreaks and epidemics over the last few decades. This literature review summarizes the available epidemiological data for this region between 1945 and 2010. Incidence rates and serogroup distribution differ from country to country and over time. Serogroups A, B, and C have all been major causes of meningococcal disease since the 1970s. In the last decade serogroups W135 and Y may now be emerging in certain countries, with serogroup A virtually disappearing. Although progress has been made in improving and coordinating the surveillance of invasive disease, the uniformity and quality of reported data reflect the fact that the current surveillance systems focus on passive rather than active reporting, hence the reliability of data may vary between countries. Consideration of vaccination policies to control meningococcal disease can only be made with a sufficient understanding of the changing epidemiology in the region.