Incidence Of Meningococcal Meningitis Research Articles

Economic evaluation on meningococcal vaccination strategies among children under nine years of age in Zhejiang province, China.

Meningococcal vaccination in Chinese national immunization program (NIP) includes polysaccharide vaccine against Neisseria meningitidis serogroup A (MPV-A) and polysaccharide vaccine against Neisseria meningitidis serogroup A and C(MPV-AC). This study aimed to assess the cost-effectiveness of an alternative strategy using polysaccharide conjugate vaccine against Neisseria meningitidis serogroup A,C,W,Y(MCV-ACWY) and polysaccharide vaccine against Neisseria meningitidis serogroup A,C,W,Y(MPV-ACWY). From a societal perspective, we constructed a decision tree-Markov model to simulate the economic and health consequences of meningococcal disease in a 2023 birth cohort with the current meningococcal vaccination strategy and the alternative. Parameters of epidemiology, vaccine efficacy, cost, and utility were extracted from database and previous literatures. The sensitivity analysis was implemented to evaluate the robustness of the model. Compared to the current practice, the alternative strategy could avoid 513 meningococcal disease cases, 53 sequelae and 47 deaths. The ICER was estimated at $16899.81 /QALY, under the threshold of one time of the GDP per capita of Zhejiang province in 2023. The incidence of meningococcemia, the incidence of meningococcal meningitis, the case fatality of meningococcemia, the vaccine efficacy of MCV-ACWY and the price of MCV-ACWY would influence the cost-effectiveness of the meningococcal vaccination strategies. At the threshold, the probability of cost-effectiveness was 14.76% for the current strategy and 55.98% for the alternative strategy, respectively. The current meningococcal vaccination strategy had effectively prevented meningococcal disease at a low cost, but with limited serogroup coverage. Strategy using MCV-ACWY and MPV-ACWY could increase health benefits at a substantial cost at a cost-effective manner.

An Outbreak of Serogroup Y Meningococcal Meningitis in a Private Secondary Vocational School - Guangzhou City, Guangdong Province, China, 2023.

The inclusion of meningococcal vaccines in the National Immunization Program (NIP) over several years has significantly reduced the incidence of meningococcal meningitis in China to historic lows. Worldwide, there has been a diversification of meningococcal serogroups, leading to a shift in dominant serogroups in China from serogroup A to serogroups C and B, accompanied by a rise in reports of serogroups Y and W. An outbreak of serogroup Y Neisseria meningitidis (Nm) in a secondary vocational school involved a single confirmed severe case and 24 individuals with laboratory-confirmed Nm carriage. Epidemiological investigation revealed that the outbreak was localized to the classroom of the confirmed case. Prolonged close contact within a confined space was identified as a significant risk factor for Nm transmission. The genotype sequence identified was type 1655 (ST-1655), which is categorized under clonal complex 23 (CC-23) and bears resemblance to 8 previously confirmed cases of serogroup Y meningococcal meningitis within Guangdong Province. This suggests that serogroup Y infections continue to sporadically emerge and have become prevalent strains. This outbreak underscores the critical need to enhance surveillance of meningococcal serogroups and population carrier, and advocate for vaccination with MenY-containing vaccines.

An Assessment of the Relationship between Built Environment and Socioeconomic Factors with the Incidence of Meningococcal Meningitis in Kaduna Urban Area, Nigeria

Meningococcal meningitis is an airborne disease that has been a threat to human life in many regions of the world, especially in West Africa. The disease has caused permanent physical impairment to some of its victims and many lives have been lost due to the disease. Factors that are associated with the incidence of the disease which are geographically referenced include built environment, geographical location and climatic conditions. Others are socioeconomic and demographic factors. This study established the relationship between built environment and socioeconomic factors with the incidence of the disease. Data that were used include the incidences of the disease from 2007 to 2011, housing conditions, population density, number of house ownership, employment, income level, and the number of hospitals, schools and refuse dumps. Neighborhoods were used as the unit of analysis in the study. The method of analyzing the data includes factor analysis and some statistical techniques in Geographical Information System such as the Ordinary Least Square (OLS). The findings of the study reveal the spatial variations of the incidence of Meningococcal meningitis in Kaduna Urban Area (KUA). The study recommends that there should be strict observance of the development control regulations especially at the high density residential neighborhood. The model can also be used for other communicable disease to ensure the health of the public.

The epidemiology of meningococcal meningitis: multicenter, hospital-based surveillance of meningococcal meningitis in Iraq

ObjectivesOutbreaks of Neisseria meningitidis have reached alarming levels due to the pathogen's ability to cause severe complications, presenting as meningitis or septicemia. Our study reports the results of the first wide-scale surveillance of meningococcal meningitis in Iraq. MethodsThe study included all consecutive cases of clinically suspected meningitis between June 2018 and May 2020 at 18 major hospitals around Iraq (n = 2314). Laboratory analysis of biological samples and real-time polymerase chain reaction tests were conducted to confirm bacterial etiology. Demographical and medical data were collected for statistical analysis. ResultsIn total, 370 patients were confirmed to have bacterial meningitis (215 had N. meningitidis, 154 had Streptococcus pneumoniae, and one case had Haemophilus influenzae type b). The most common N. meningitidis serogroup was B (77.7%), followed by W (18.1%) and X (4.2%). The annual incidence rate of N. meningitidis per 100 000 population was 0.86, with the highest being in Karbala (1.52 per 100 000 population). Cases of meningococcal meningitis were more likely to occur in children younger than 15 (OR = 3.526), and in the winter (OR = 1.474). ConclusionsContinuous surveillance of N. meningitidis is necessary in Iraq, and can only be achieved through improved detection methods. The incidence of meningococcal meningitis in Iraq warrants improved vaccination programs.

340. Association between Meningococcal Meningitis and Santa Ana Winds in Mexican Children and Adolescents from Tijuana, Baja-California, Mexico

BackgroundThe Tijuana, Baja-California, and San Diego, California, USA -border, is considered to be the most transited in the world. Based on our active surveillance studies, Tijuana has the highest incidence of meningococcal meningitis (MeM) in Mexico (Chacon-Cruz E. et al.: Ther. Adv. Vaccines 2016; 4: 15–9. J. Infect. Dis. Treat. 2017; 3: 1–4. Emerg. Infect. Dis. 2011; 17: 543–6. And Ther. Adv. Vaccines 2019; 6: 1–7), and an outbreak of MeM in 2013 (Chacon-Cruz et al. Ther. Adv. Vaccines 2014; 2: 71–6). The Santa Ana Winds (SAWs) are episodic pulses of easterly, downslope, offshore flows over the coastal topography of the California Border Region: Southern California and Northern Baja-California (Mexico), occurring mostly from October to April, and are associated with very dry air, often with anomalous warming at low elevations, similar to the Harmattan winds associated with MeM outbreaks in Africa. We hypothesized that the high incidence of MeM in Tijuana is, in part, associated with SAWs. This association has never yet been described.MethodsBased on 13 years of active/prospective surveillance (2005–2018) in children > 7 days and < 16 years of age at the General Hospital of Tijuana, we identified 51 cases of MeM (25% lethality), and 30 non-meningococcal meningitis (NMeM). Association between cases per month of MeM and NMeM, with SAWs seasons (from a 65 years review: Guzman-Morales J, et al. Geophys. Res. Lett. 2016; 43: 2827–34), was calculated by Risk Ratio (RR). A z test was also used to compare proportions of MeM during SAWs seasons vs. non-SAWs seasons.ResultsFrom 51 MeM, 44 (86.27%) occurred during SAWs seasons (z test = 7.32, p< 0.0002). Cases per month during 13 years (91 months for SAWs seasons and 60 months for non-SAWs seasons) were as follow (See Figure-1):SAWs seasons: non-SAWs seasons:MeM 0.483 cases/month 0.107 cases/monthNMeM 0.186 cases/month 0.216 cases/monthRR =1.76, p=0.0002 (95% CI 1.23 to 2.49) Conclusion1. In Tijuana, Baja-California, Mexico, there is a strong association of Meningococcal Meningitis with seasons when Santa Ana Winds occur.2. Routine immunization against vs. Neisseria meningitidis should be seriously considered in the region.Disclosures All Authors: No reported disclosures

Epidemiology of Bacterial Meningitis in the Nine Years Since Meningococcal Serogroup A Conjugate Vaccine Introduction, Niger, 2010-2018.

In 2010, Niger and other meningitis belt countries introduced a meningococcal serogroup A conjugate vaccine (MACV). We describe the epidemiology of bacterial meningitis in Niger from 2010 to 2018. Suspected and confirmed meningitis cases from January 1, 2010 to July 15, 2018 were obtained from national aggregate and laboratory surveillance. Cerebrospinal fluid specimens were analyzed by culture and/or polymerase chain reaction. Annual incidence was calculated as cases per 100 000 population. Selected isolates obtained during 2016-2017 were characterized by whole-genome sequencing. Of the 21 142 suspected cases of meningitis, 5590 were confirmed: Neisseria meningitidis ([Nm] 85%), Streptococcus pneumoniae ([Sp] 13%), and Haemophilus influenzae ([Hi] 2%). No NmA cases occurred after 2011. Annual incidence per 100 000 population was more dynamic for Nm (0.06-7.71) than for Sp (0.18-0.70) and Hi (0.01-0.23). The predominant Nm serogroups varied over time (NmW in 2010-2011, NmC in 2015-2018, and both NmC and NmX in 2017-2018). Meningococcal meningitis incidence was highest in the regions of Niamey, Tillabery, Dosso, Tahoua, and Maradi. The NmW isolates were clonal complex (CC)11, NmX were CC181, and NmC were CC10217. After MACV introduction, we observed an absence of NmA, the emergence and continuing burden of NmC, and an increase in NmX. Niger's dynamic Nm serogroup distribution highlights the need for strong surveillance programs to inform vaccine policy.

Meningococcal Vaccines: Current Status and Emerging Strategies.

Neisseria meningitidis causes most cases of bacterial meningitis. Meningococcal meningitis is a public health burden to both developed and developing countries throughout the world. There are a number of vaccines (polysaccharide-based, glycoconjugate, protein-based and combined conjugate vaccines) that are approved to target five of the six disease-causing serogroups of the pathogen. Immunization strategies have been effective at helping to decrease the global incidence of meningococcal meningitis. Researchers continue to enhance these efforts through discovery of new antigen targets that may lead to a broadly protective vaccine and development of new methods of homogenous vaccine production. This review describes current meningococcal vaccines and discusses some recent research discoveries that may transform vaccine development against N. meningitidis in the future.

Epidemiology of community-acquired bacterial meningitis.

The epidemiology of bacterial meningitis has been dynamic in the past 30 years following introduction of conjugated vaccines against Haemophilus influenzae type B, Streptococcus pneumoniae and Neisseria meningitidis. The purpose of this review is to describe recent developments in bacterial meningitis epidemiology. The incidence of bacterial meningitis in Western countries (Finland, Netherlands, and the United States) gradually declined by 3-4% per year to 0.7-0.9 per 100 000 per year in the past 10-20 years. In African countries (Burkina Faso and Malawi), incidence rates are still substantially higher at 10-40 per 100 000 persons per year. Introduction of pneumococcal conjugate vaccines have not consistently decreased overall pneumococcal meningitis incidence because of serotype replacement. Following the introduction of serogroup A and C meningococcal vaccines, the incidence of meningococcal meningitis because of these serogroups strongly decreased. Novel outbreaks in the African meningitis belt by serogroup C and increased incidence of serogroup W in the United Kingdom and the Netherlands were observed recently. Bacterial meningitis remains an important infectious disease, despite a gradual decline in incidence after large-scale vaccination campaigns. Further development of vaccines with broader coverage is important, as is continuous surveillance of bacterial meningitis cases.

Bacterial meningitis epidemiology and return of Neisseria meningitidis serogroup A cases in Burkina Faso in the five years following MenAfriVac mass vaccination campaign.

BackgroundHistorically, Neisseria meningitidis serogroup A (NmA) caused large meningitis epidemics in sub-Saharan Africa. In 2010, Burkina Faso became the first country to implement a national meningococcal serogroup A conjugate vaccine (MACV) campaign. We analyzed nationwide meningitis surveillance data from Burkina Faso for the 5 years following MACV introduction.MethodsWe examined Burkina Faso’s aggregate reporting and national laboratory-confirmed case-based meningitis surveillance data from 2011–2015. We calculated incidence (cases per 100,000 persons), and described reported NmA cases.ResultsIn 2011–2015, Burkina Faso reported 20,389 cases of suspected meningitis. A quarter (4,503) of suspected meningitis cases with cerebrospinal fluid specimens were laboratory-confirmed as either S. pneumoniae (57%), N. meningitidis (40%), or H. influenzae (2%). Average adjusted annual national incidence of meningococcal meningitis was 3.8 (range: 2.0–10.2 annually) and was highest among infants aged <1 year (8.4). N. meningitidis serogroup W caused the majority (64%) of meningococcal meningitis among all age groups. Only six confirmed NmA cases were reported in 2011–2015. Five cases were in children who were too young (n = 2) or otherwise not vaccinated (n = 3) during the 2010 MACV mass vaccination campaign; one case had documented MACV receipt, representing the first documented MACV failure.ConclusionsMeningococcal meningitis incidence in Burkina Faso remains relatively low following MACV introduction. However, a substantial burden remains and NmA transmission has persisted. MACV integration into routine childhood immunization programs is essential to ensure continued protection.

Effects of meteorological factors on the incidence of meningococcal meningitis.

Substantial climate changes have led to the emergence and re-emergence of various infectious diseases worldwide, presenting an imperative need to explore the effects of meteorological factors on serious contagious disease incidences such as that of meningococcal meningitis (MCM). The incidences of MCM and meteorology data between 1981 and 2010 were obtained from Chaoyang city. Structure Equation Modeling was used to analyze the relationships between meteorological factors and the incidence of MCM, using the LISREL software. The SEM results showed that Adjusted Goodness of Fit Index (AGFI) = 0.30, Goodness of Fit Index (GFI) = 0.63, and Root Mean Square Error of Approximation (RMSEA) = 0.31. Humidity and temperature both had negative correlations with MCM incidence, with factor loads of -0.32 and -0.43, while sunshine was positively correlated with a factor load of 0.42. For specific observable variables, average air pressure, average evaporation, average air temperature, and average ground temperature exerted stronger influence, with item loads between observable variables and MCM incidence being -0.42, 0.34, -0.32, and -0.32 respectively. Public health institutions should pay more attention to the meteorological variables of humidity, sunshine, and temperature in prospective MCM control and prevention.

Incidence, carriage and case-carrier ratios for meningococcal meningitis in the African meningitis belt: a systematic review and meta-analysis.

BackgroundTo facilitate the interpretation of meningococcal meningitis epidemiology in the “African meningitis belt”, we aimed at obtaining serogroup-specific pooled estimates of incidence, carriage and case-carrier ratios for meningococcal meningitis in the African meningitis belt and describe their variations across the endemic, hyperendemic and epidemic context.MethodsWe conducted a systematic review and meta-analysis of studies reporting serogroup-specific meningococcal meningitis monthly incidence and carriage in the same population and time period. Epidemiological contexts were defined as endemic (wet season, no epidemic), hyperendemic (dry season, no epidemic), and epidemic (dry season, epidemic).FindingsEight studies reporting a total of eighty pairs of serogroup-specific meningococcal meningitis incidence and carriage estimates were included in this review. For serogroup A, changes associated with the transition from endemic to hyperendemic incidence and from hyperendemic to epidemic incidence were 15-fold and 120-fold respectively. Changes in carriage prevalence associated with both transitions were 1-fold and 30-fold respectively. For serogroup W and X, the transition from endemic to hyperendemic incidence involved a 4-fold and 1•1-fold increase respectively. Increases in carriage prevalence for the later transition were 7-fold and 1•7-fold respectively. No data were available for the hyperendemic-epidemic transition for these serogroups. Our findings suggested that the regular seasonal variation in serogroup A meningococcal meningitis incidence between the rainy and the dry season could be mainly driven by seasonal change in the ratio of clinical cases to subclinical infections. In contrast appearance of epidemic incidences is related to a substantial increase in transmission and colonisation and to lesser extent with changes in the case-carrier ratio.ConclusionSeasonal change in the rate of progression to disease given carriage together with variations in frequency of carriage transmission should be considered in models attempting to capture the epidemiology of meningococcal meningitis and mainly to predict meningitis epidemics in the African meningitis belt.

Meningitis and climate: from science to practice

Meningococcal meningitis is a climate sensitive infectious disease. The regional extent of the Meningitis Belt in Africa, where the majority of epidemics occur, was originally defined by Lapeysonnie in the 1960s. A combination of climatic and environmental conditions and biological and social factors have been associated to the spatial and temporal patterns of epidemics observed since the disease first emerged in West Africa over a century ago. However, there is still a lack of knowledge and data that would allow disentangling the relative effects of the diverse risk factors upon epidemics. The Meningitis Environmental Risk Information Technologies Initiative (MERIT), a collaborative research-to-practice consortium, seeks to inform national and regional prevention and control strategies across the African Meningitis Belt through the provision of new data and tools that better determine risk factors. In particular MERIT seeks to consolidate a body of knowledge that provides evidence of the contribution of climatic and environmental factors to seasonal and year-to-year variations in meningococcal meningitis incidence at both district and national scales. Here we review recent research and practice seeking to provide useful information for the epidemic response strategy of National Ministries of Health in the Meningitis Belt of Africa. In particular the research and derived tools described in this paper have focused at “getting science into policy and practice” by engaging with practitioner communities under the umbrella of MERIT to ensure the relevance of their work to operational decision-making. We limit our focus to that of reactive vaccination for meningococcal meningitis. Important but external to our discussion is the development and implementation of the new conjugate vaccine, which specifically targets meningococcus A.

Bacterial meningitis in children in Iceland, 1975–2010: A nationwide epidemiological study

Bacterial meningitis is a serious and potentially rapid life-threatening disease. Therefore, to ensure appropriate treatment, early recognition of signs and symptoms is imperative, along with knowledge of the epidemiology and microbiology of the disease. A long-term, nationwide epidemiological study of bacterial causes of meningitis in children (≤ 18 y) in Iceland during the period 1975-2010 was carried out. A detailed chart review was performed of all cases diagnosed in 1995-2010. A total of 477 children were diagnosed with bacterial meningitis during the period 1975-2010. Of these, 67% were aged under 5 y. The most common pathogens were Neisseria meningitidis (n = 265), Haemophilus influenzae (n = 132), Streptococcus pneumoniae (n = 47), and Streptococcus agalactiae (n = 19); their incidences varied according to age. The age-specific incidence (cases/100,000/y) dropped from 26 in 1975 to 1 in 2010 (p < 0.001). The most common symptoms during the period 1995-2010 were fever (92%), vomiting (67%), nuchal rigidity (60%), and rashes/petechiae (51%). H. influenzae type b disappeared following implementation of Hib vaccination in 1989, and, likewise, the incidence of meningococcal meningitis fell significantly after vaccination against meningococcus serogroup C was initiated in 2002 (p < 0.001). The overall 30-day case fatality rate of bacterial meningitis was 4.4% and remained unchanged during the study period. The incidence of childhood bacterial meningitis has been reduced significantly by successful vaccinations against H. influenzae type b and N. meningitidis serogroup C. Nevertheless, the case fatality rate has remained unchanged and thus the disease is still a serious threat to childhood health. Further prevention by novel vaccines and improved management of childhood meningitis is an exciting challenge.

Meningitis and Encephalitis

: Neurologists have a vital role in the recognition of meningitis and encephalitis, the accurate evaluation and interpretation of CSF studies, and the management and prevention of the neurologic complications of CNS infectious diseases. ;: Although the tetravalent meningococcal glycoconjugate vaccine has decreased the incidence of meningococcal meningitis, the vaccine does not contain serogroup B, which is responsible for one-third of cases of meningococcal disease. Thus, meningitis due to Neisseria meningitidis is still a concern in a vaccinated individual. Empiric therapy for meningitis associated with sinusitis, otitis, or mastoiditis should include antibiotic therapy for anaerobes. An organism that classically causes a subacute or chronic meningitis, such as Mycobacterium tuberculosis, may on occasion present with an acute onset of symptoms. ;: Unlike most other diseases, the management of patients with suspected meningitis or encephalitis begins with empiric therapy. The etiologic organism cannot always be identified. The goal is to identify those that are treatable, provide supportive care for those that are not, and, when possible, prevent the neurologic complications of these infections.

Meningococcal Meningitis Prevention Programs for College Students: A Review of the Literature

The incidence of meningococcal meningitis in college students is higher than in other populations. College students, especially 1st-year students living in dormitories or residence halls, are among those at highest risk of developing the disease. It is estimated that immunization can prevent up to 83% of cases among adolescents and college students. A review of the literature was undertaken to identify and critique the research-based prevention programs that are focused on college students. An extensive search of the Cochrane Database of systematic reviews, Medline, PubMed, and CINAHL was undertaken. The Journal of American College Health was hand searched, and bibliographies were reviewed for studies not otherwise identified. Four publications met the search criteria. These studies were reviewed and graded for level of evidence. One study could not be compared with the other three because of its lack of detail. Of the other three studies, two were descriptive and factors were identified that related to vaccination and nonvaccination in the college student population (both Evidence Grade C). Only one study was described that included an educational intervention, which resulted in increased vaccination rates in a college student population (Evidence Grade B). The published literature is severely limited in the area of meningococcal meningitis prevention programs in the at-risk college student population. A critical need exists for controlled studies to test the interventions that are most effective in this population as well as broader-based studies to further identify those students at increased risk for the disease as well as for nonvaccination.

Association between combined properdin and mannose-binding lectin deficiency and infection with Neisseria meningitidis

Background Individuals genetically deficient of properdin are more susceptible to meningococcal disease. Likewise low concentration or decreased biological activity of mannose-binding lectin (MBL) is associated with higher incidence of bacterial infections during childhood. In this study we report our findings in a Danish family with a remarkably high incidence of meningococcal meningitis—in total four cases, one of them fatal. Methods Properdin and MBL were quantified by ELISA and the properdin gene was screened for sequence variations using denaturing high-performance liquid chromatography (DHPLC) and subsequent sequencing of abnormal patterns. The MBL gene was genotyped for the three known variant alleles ( B, C and D) as well as three promoter polymorphisms (−221 Y/ X, −550 H/ L and +4 P/ Q). Results Two out of six males with undetectable properdin activity had meningitis. They had also low MBL serum levels or carried an MBL variant allele, whereas high MBL concentrations were measured in three out of four properdin deficient males—without meningitis. A splice site mutation in exon 10 (c.1487-2A > G) was found in the properdin gene and co segregated with biochemically measured properdin deficiency. Conclusion Our results indicate that a combined deficiency of both properdin and MBL increases the risk of infection with Neisseria meningitidis and stress the importance of epistatic genetic interactions in disease susceptibility.

Incidence and etiological agents of bacterial meningitis among children

To expand upon the limited comprehensive population-based data for childhood bacterial meningitis in Eastern Europe, the present study was conducted in the Iasi and Constanta districts of Romania. From March 2000 through March 2002, children <5 years of age hospitalized for bacterial meningitis were enrolled in a prospective surveillance study. A total of 56 cases of bacterial meningitis were identified, including 37 due to Neisseria meningitidis (22 per 100,000 per year), 13 due to Haemophilus influenzae type b (7.6 per 100,000 per year), and six due to Streptococcus pneumoniae (3.5 per 100,000 per year). Of the 31 meningococcal isolates that were serotyped, 12 were serogroup A, eight were serogroup B, and 11 were serogroup C. Among all cases of bacterial meningitis, 25 occurred in children <1 year of age, including those due to meningococci (n=14), H. influenzae type b (n=7), pneumococci (n=3), and Klebsiella pneumoniae (n=1). In Romania the incidence of H. influenzae type b meningitis is similar to that found in other areas of Southern and Eastern Europe during the pre-vaccination era, and the incidence of meningococcal meningitis is one of the highest yet found in Europe. An unexpectedly high proportion of these meningococcal meningitis cases is due to serogroup A. Disease burden could be substantially reduced through the introduction of H. influenzae type b conjugate vaccine and, when available, meningococcal conjugate vaccine protective against serogroups A, B and C.

A critical review of control strategies against meningococcal meningitis epidemics in sub-Saharan African countries.

The control strategy of meningitis epidemics in sub-Saharan countries, although reexamined regularly, is based on epidemiological, immunological and logistical considerations put forward at the end of the 1970s. It comprises organizing large-scale vaccinations in the event of a declared epidemic. The obvious failure of this strategy recommended by the World Health Organization (WHO) necessitates evaluation of the emergency vaccination criteria. Despite current controversy on the immunogenicity of the polysaccharide vaccine, its safety, effectiveness in the field and low cost could justify the reopening of a debate on its use in routine vaccination. Routine--or preventive--vaccination could significantly reduce the incidence of meningococcal meningitis and its severity. The conjugate vaccine, when available, will constitute an additional advantage in the prevention of meningococcal meningitis. A strategy combining both polysaccharide and conjugate vaccines according to the population targets and possibilities for funding remain to be defined.

A cost-effectiveness analysis of vaccination strategies against N. meningitidis meningitis in sub-Saharan African countries

This analysis evaluates the cost-effectiveness (C/E) of routine vaccination against Neisseria meningitidis. Three different preventive strategies are analyzed: mass vaccination during epidemics (the current standard of care), routine preventive vaccination and a combination strategy of routine vaccination with mass vaccination during epidemics. A Markov model is used to simulate the epidemics of meningitis in a cohort of 5-year old children and compare these different strategies. The results show that mass vaccination strategy is dominated by the two other strategies. The incremental C/E ratios are US$50/QALY for the routine vaccination, and US$199/QALY for the combination strategy. The costs per fatal case averted are US$1161 for the routine vaccination, and US$2397 for the combination strategy. The C/E ratios are sensitive to: the incidence of meningococcal meningitis, the costs of treating cases, the costs of routine vaccination and the costs and effectiveness of mass immunization campaign. However the rank ordering of the strategies is almost never altered. In conclusion, the results of this analysis suggest that mass vaccination in sub-Saharan Africa in case of epidemics should be reconsidered. Routine vaccination against meningococcal meningitis at an early age, with or without mass vaccination during epidemics is more effective, with a C/E ratio within the range of other vaccination strategies currently in place in Africa.

Serotypes and polyacrylamide gel electrophoresis types among disease-associated isolates of group B Neisseria meningitidis in Spain, 1976-1979.

A high annual incidence of meningococcal meningitis and septicemia occurred in Spain from 1976 through 1980 with a peak of 19 cases per 100,000 population in 1979. Approximately 80% were caused by group B Neisseria meningitidis. Studies were undertaken to determine the distribution of groups, outer membrane protein serotypes and polyacrylamide gel electrophoresis (PAGE) types among 338 disease-associated group B isolates from six regions of Spain. The related serotypes 1, 8, and 15 accounted for 38% (129 of 338) of the isolates. Serotype 2, the major disease type in the United States, was responsible for 14% (48 of 338) of the disease in Spain and was prevalent in only one region. Forty-three percent (146 of 338) were nonserotypable. The predominant PAGE type among the nonserotypable strains was PAGE type IV (79%). These studies demonstrate the necessity of surveillance for selection of suitable serotypes to be included in protective group B meningococcal vaccines.