PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “MENINGOCOCCAL INFECTIONS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources

The role of economic evaluation in vaccine decision making: focus on meningococcal group C conjugate vaccine.

In recent years, several countries have experienced increases in the incidence of serogroup C meningococcal disease. It can be controlled with older polysaccharide vaccines and particularly the recently developed conjugate vaccines. For 21 developed countries, we investigated the role that economic evaluation played in the decision to introduce the conjugate vaccine into either the routine childhood vaccination schedule, as a mass vaccination 'catch-up' campaign or not at all. A literature review was performed and experts from these countries were contacted. For six countries, we identified published economic evaluations for meningococcal C conjugate vaccination. In four of them (Australia, Canada [Quebec], The Netherlands and the UK) the analyses were performed before a decision about the use of the conjugate vaccine was made. In all of these countries, the economic evaluation offered guidance as to the most efficient way to add the conjugate vaccine to the routine infant immunisation schedule and, in three countries, this advice was adopted by decision makers. In Portugal and Switzerland, initial vaccination decisions were made without the economic evaluations that are influencing current decision making. Of the countries without economic evaluations, six implemented vaccination programmes. Overall, there was a positive correlation between the reported incidence of meningococcal C disease and (a) the decision to vaccinate and (b) performing an economic evaluation. All economic evaluations were modelling studies. The reported cost-effectiveness ratios were sensitive to the age of vaccination, the future meningococcal incidence, vaccine price and some methodological characteristics that varied widely between studies making direct comparisons difficult. In conclusion, in almost all countries where economic evaluations for meningococcal C conjugate vaccinations have been conducted, their results had an important role in the decision-making process. However, in most countries with strongly increasing meningococcal incidence, public health considerations took precedence. In order to improve the international comparability of such studies, firmer national and international modelling guidelines and better adherence to such guidelines seem necessary.

Cost-Benefit Analysis↗

Meningococcal disease in international travel: vaccine strategies.

International travel and migration facilitate the rapid intercontinental spread of meningococcal disease. Serogroup A, and to a lesser extent serogroup C, have been responsible for pandemics in the past (mainly in Africa), but in recent years there was an international outbreak due to W135 related to the Hajj pilgrimage. The high carriage rates, persistence and transmissibility, in combination with the high case fatality rate of the Hajj-associated W135 outbreak clone, certainly raise considerable concern about the public health consequences of widespread dissemination of this organism and the potential for future epidemics. Indeed, the now evolving W135 epidemic in Africa mandates that the bivalent meningococcal vaccine should be replaced by the tetravalent meningococcal vaccine, covering A, C, Y and W135 serogroups. The currently available polysaccharide tetravalent meningococcal vaccine, albeit associated with high seroconversion and efficacy rates, has several shortcomings: it is not immunogenic in young children, duration of protective immunity is short, and it has minimal or no effect on nasopharyngeal carriage and therefore transmission of the organism. Immunogenicity of polysaccharide vaccines can be improved by chemical conjugation to a protein carrier, thereby eliciting a T-cell-dependent antibody response. In contrast to polysaccharide vaccines, conjugate vaccines are immunogenic in young infants, induce long-term protection, and reduce nasopharyngeal carriage. The tetravalent conjugate vaccine will be a leap forward in the control of meningococcal epidemics in affected countries. It will also boost the uptake of meningococcal vaccines in travelers, because the duration of protection is longer and it eliminates the problem of immune hyporesponsiveness of serogroup C with repeated dosing. The small risk of travel-associated disease for the general traveler and the unpredictable nature of epidemics make it difficult to provide evidence-based vaccine recommendations. The current recommendation is to vaccinate all Hajj pilgrims, travelers to areas with current outbreaks, travelers to the sub-Saharan meningitis belt, and high-risk individuals (i.e., those with immunodeficiencies).

Disease Outbreaks↗

[Meningococcal vaccines: present status and perspectives].

Neisseria meningitidis can cause asymptomatic carriage, followed by acquired immunity, or septicaemia, meningitis, septic arthritis or pericarditis. Vaccination induces protective bactericidal antibodies to invasive diseases. Meningococcal capsular polysaccharides are immunoprotective antigens from which vaccines are produced against serogroups A, C, Y and W135, including conjugate vaccines against serogroup C. There is no available vaccine against serogroup B, but outermembrane protein-based vaccines against this serogroup are currently being evaluated. Polysaccharide meningococcal vaccines are effective, but their strictly serogroup-specific efficacy raises concerns about the possible selection of escape variants. Therefore, meningococcal polysaccharide vaccines, either plain or conjugated, are indicated against the clonal expansion of strains whose serogroup has been properly identified and corresponds to the vaccine valence.

Humans↗

Vaccination campaign following an increase in incidence of serogroup C meningococcal diseases in the department of Puy-de-Dôme (France).

In the department of Puy-de-Dôme, France, 17 cases of invasive meningococcal disease C were notified between March 2001 and the first week of 2002. Among the 15 confirmed cases, 11 (73%) were serogroup C, 2 (13%) serogroup B, and 2 could not be identified. The rapid increase in the number of cases in a period of low endemicity for the rest of the country and the severity of the disease (case fatality ratio 27%, purpura fulminans 64%) led the health authorities to initiate a vaccination campaign targeting children and young adults from 2 months up to 20 years living in a limited area of the department. Around 80,000 people were immunised between 16/01/02 and 09/02/02. More than half of the 1390 immediate side effects were headache and dizziness. As of mid-March, no further case of meningococcal disease has been notified since 6 January.

Adolescent↗

Development and characterization of anti-idiotype based peptide and DNA vaccines which mimic the capsular polysaccharide of Neisseria meningitidis serogroup C.

Anti-idiotypic antibodies and peptides which mimic antigens may offer an alternate strategy for converting a thymus-independent (TI) antigen to a thymus dependent (TD) antigen. We have developed an anti-idiotype based peptide mimic of the capsular polysaccharide of N. meningitidis serogroup C (MCPS) which induces a T-dependent protective immune response in mice. Subsequent studies have demonstrated that immunization of severe combined immunodeficient mice reconstituted with human B cells respond to immunization with the MCPS peptide mimic with bactericidal anti-polysaccharide directed antibody response. We hypothesized that administration of a DNA vaccine resulting in endogenous expression of this carbohydrate peptide mimic would induce anti-MCPS antibodies.

Animals↗

Neisseria meningitidis C:2b:P1.2,5 with intermediate resistance to penicillin, Portugal.

For 1 year, serogroup, serotype, serosubtype, and penicillin susceptibility of meningococci circulating in various regions in Portugal were evaluated. Most frequent phenotypes were B:4:P1.15 (13.4%) and C:2b:P1.2,5 (75.9%), which are also common in Spain. Overall, 27.5% of C:2b:P1.2,5 strains showed intermediate resistance to penicillin. Laboratory-based surveillance of meningococcal infection in Portugal provides important information to assess the adequacy of public health measures.

Humans↗

An exercise in communication:-analysis of calls to a meningococcal disease hotline.

We describe our experience with a hotline which was set up to deal with enquiries relating to a secondary school mass vaccination campaign against meningococcal disease. Three thousand, three hundred calls were received over 6 days, mostly from the general public but also from contacts of the school and health practitioners. The hotline served as an important means of providing consistent advice and reassurance to the public and reduced the burden of calls to hospitals and public health units.

Australia↗

Meningococcal carriage in adolescents and young adults in Kuwait.

BACKGROUND: Neisseria meningitidis is a major cause of invasive meningococcal disease (IMD), with asymptomatic carriage playing a crucial role in transmission. Adolescents (15-17 years) and young adults (18-20 years) have the highest carriage rates, yet data from Kuwait remain limited. This study aimed to estimate the prevalence of N. meningitidis carriage among adolescents and young adults in Kuwait. METHODS: A cross-sectional study was conducted from July 2023 to May 2024, enrolling 1,398 participants aged 15-20 years. Randomly selected individuals provided oropharyngeal swabs, and demographic, behavioral, and vaccination data were collected via standardized questionnaires. Carriage prevalence was determined using selective culture-based methods. Whole genome sequencing was performed on culture-confirmed isolates. Descriptive statistics were used to summarize participant characteristics; carriage prevalence was reported as proportions, and associations were explored using Fisher's exact or chi-square tests and logistic regression where feasible. RESULTS: The overall meningococcal carriage rate was 0.21% (3/1,398). All isolates were non-groupable (NG), with one carrying the capsule null locus (CNL). Self-reported MenACWY vaccination coverage was 94.8%. No significant associations between demographic, geographic, or behavioral factors and carriage status were identified due to the small number of positive cases. CONCLUSION: This study provides a population-based estimate of meningococcal carriage among adolescents and young adults in Kuwait using a random sampling approach. The low carriage rate, alongside high vaccination coverage, suggests that existing immunization programs in Kuwait may be effective in reducing N. meningitidis transmission. However, the presence of NG strains stresses the need for continued surveillance. Further research is required to evaluate long-term vaccination impacts and potential gaps in disease protection.

Humans↗

The new meningococcal conjugate vaccine. A profile of its safety, efficacy, and indications for use.

Meningococcal disease is a serious illness affecting all age-groups. Infants under 1 year of age, adolescents, and young adults are also especially susceptible. An effective quadrivalent meningococcal plain polysaccharide vaccine has been available for decades. However, inherent limitations of plain polysaccharide vaccines include limited duration of immunity, the potential for hyoporesponsiveness with repeated vaccinations, and ineffectiveness in children under age 2 years. The recently developed and licensed quadrivalent meningococcal conjugate vaccine should prove to provide important advantages over the plain polysaccharide vaccine. In this article, Dr. Pichichero discusses these advantages, current recommendations for administration, and prospects for broader vaccine coverage.

Humans↗

Protective activity of monoclonal antibodies to genome-derived neisserial antigen 1870, a Neisseria meningitidis candidate vaccine.

Genome-derived neisserial Ag (GNA) 1870 is a meningococcal vaccine candidate that can be subdivided into three variants based on amino acid sequence variability. Variant group 1 accounts for approximately 60% of disease-producing group B isolates. The Ag went unrecognized until its discovery by genome mining because it is expressed in low copy number by most strains. To investigate the relationship between Ab binding to GNA1870 and complement-mediated protective functions, we prepared a panel of four murine IgG mAbs against rGNA1870 (variant 1) and evaluated their activity against nine genetically diverse encapsulated Neisseria meningitidis strains expressing subvariants of variant 1 GNA1870. Based on flow cytometry with live encapsulated bacteria, surface accessibility of the epitopes recognized by the mAbs appeared to be low in most strains. Yet mAb concentrations <1 to 5 micro g/ml were sufficient to elicit bactericidal activity with human complement and/or activate C3b deposition on the bacterial surface. Certain combinations of mAbs were highly bactericidal against strains that were resistant to bactericidal activity of the respective individual mAbs. The mAbs conferred passive protection against bacteremia in infant rats challenged by strains resistant to bacteriolysis, and the protective activity paralleled the ability of the mAb to activate C3b deposition. Thus, despite low GNA1870 surface exposure, anti-GNA1870 variant 1 Abs are bactericidal and/or elicit C3b deposition and confer protection against bacteremia caused by encapsulated N. meningitidis strains expressing GNA1870 subvariant 1 proteins. The data support GNA1870 as a promising vaccine candidate for prevention of meningococcal group B disease caused by GNA1870 variant 1 strains.

Amino Acid Sequence↗

Binding of the complement inhibitor C4bp to serogroup B Neisseria meningitidis.

Neisseria meningitidis (meningococcus) is an important cause of meningitis and sepsis. Currently, there is no effective vaccine against serogroup B meningococcal infection. Host defense against neisseriae requires the complement system (C) as indicated by the fact that individuals deficient in properdin or late C components (C6-9) have an increased susceptibility to recurrent neisserial infections. Because the classical pathway (CP) is required to initiate efficient complement activation on neisseriae, meningococci should be able to evade it to cause disease. To test this hypothesis, we studied the interactions of meningococci with the major CP inhibitor C4b-binding protein (C4bp). We tested C4bp binding to wild-type group B meningococcus strain (H44/76) and to 11 isogenic mutants thereof that differed in capsule expression, lipo-oligosaccharide sialylation, and/or expression of either porin (Por) A or PorB3. All strains expressing PorA bound radiolabeled C4bp, whereas the strains lacking PorA bound significantly less C4bp. Increased binding was observed under hypotonic conditions. Deleting PorB3 did not influence C4bp binding, but the presence of polysialic acid capsule reduced C4bp binding by 50%. Bound C4bp remained functionally active in that it promoted the inactivation of C4b by factor I. PorA-expressing strains were also more resistant to C lysis than PorA-negative strains in a serum bactericidal assay. Binding of C4bp thus helps Neisseria meningitidis to escape CP complement activation.

Amino Acid Sequence↗

Safety and immunogenicity of a meningococcal (Groups A, C, Y, W-135) polysaccharide diphtheria toxoid conjugate vaccine in healthy children aged 2 to 10 years in Chile.

Immune responses to meningococcal conjugate (Menactra; MCV-4) and plain polysaccharide (Menomune-A/C/Y/W-135; PSV-4) vaccines against serogroups A, C, Y, and W-135 were assessed in 220 of 1037 Chilean children aged 2 to 10 years participating in a comparative safety trial. Both vaccines were generally well tolerated. Geometric mean serum bactericidal antibody (SBA) titers 28 days postvaccination were comparable in both groups for all four serogroups. Seroconversion was evident in > 97% of MCV-4 and > 90% of PSV-4 vaccinees who tested seronegative at baseline. Menactra safely induced broad and robust immune responses against serogroups A, C, Y and W-135 in this population.

Child↗