Neisseria meningitidis is a major world-wide cause of meningitis. N. meningitidis related diseases have become more pronounced in the last decade and changes in meningococcal-associated disease have opened new opportunities for prevention and vaccine development. Although multivalent vaccines have been developed against the N. meningitidis serogroups A, C, W-135, and Y, four of the most common serogroups, the diversity of N. meningitidis has increased the number of challenges for the development of an effective vaccine against all currently identified strains. Without the development of a vaccine against serogroup B, it will be difficult to effectively prevent global meningococcal disease. This review provides a background on N. meningitidis biology and focuses on the current status of meningococcal research and vaccine development. In addition, the efficacy of the currently marketed N. meningitidis vaccines will be discussed.
"However, the value of polysaccharide vaccines is limited as they do not induce immunologic memory and have limited effectiveness in children <5 years of age, leaving this particularly vulnerable age group unprotected  . In addition , MPSV4s do not induce herd immunity and have been found to invoke hyporesponsiveness following subsequent immunization with either MPSV4 or meningococcal conjugate vaccines    . Until recently, one MPSV4 (Menomune ® ; sanofi pasteur, Swiftwater , Pennsylvania, USA) was the only quadrivalent vaccine available in the USA to protect against serogroups A, C, W-135, and Y. "
[Show abstract][Hide abstract] ABSTRACT: Meningococcal disease incidence is highest in infants, but a significant burden of disease also occurs in children. In this Phase II, single-centre US study, 619 healthy children (2-10 years of age) received one dose of an investigational quadrivalent meningococcal CRM(197)-conjugated vaccine (MenACWY-CRM) or a licensed quadrivalent meningococcal polysaccharide vaccine (MPSV4). Immunogenicity was assessed using the serum bactericidal assay with human complement (hSBA) at 1 and 12 months post-vaccination. Local and systemic reactions were recorded for 7 days, all adverse events (AEs) for 1 month, and medically significant and serious AEs (SAEs) for 12 months post-vaccination. For all four serogroups, more MenACWY-CRM recipients achieved an hSBA titre >or=1:4 at 1 month post-vaccination (A: 82%; C: 83%; W-135: 95%; Y: 91%) compared with the group that received MPSV4 (A: 45%; C: 66%; W-135: 71%; Y: 61%); this difference persisted through to 12 months post-vaccination. Both vaccines were well tolerated. In children 2-10 years of age, MenACWY-CRM induced a higher immune response than that of MPSV4, and was well tolerated.
[Show abstract][Hide abstract] ABSTRACT: A European Youth Olympic Sports Festival (EYOF), in Jaca, Northern Aragon, Spain, involving 1500 athletes, from 43 countries was held in January for 7 days. The event was marred by a case of type B Neisseria meningitidis. The usual care of the patient was performed in a local hospital. He eventually made a full recovery. The case was reported to the Local Health Authority and the National Public Health authority of the patient's country. Their advice was to treat the core case, give prophylactic therapy to the inner circle (28 athletes and officials) and surveillance of the other close contacts (84 total) with temperature and symptom review daily. They advised against further information being given to the rest of the athletes and officials, in case it might give rise to a panic situation. The dilemma of the responsible physicians was that 1500 athletes were traveling back to 43 countries within the incubation period of the bacterial meningitis. It was decided that informing each country was appropriate. This was done at the event by informing the Chef of the Missions and writing to the Secretary Generals of each National Olympic Committee attending. This was the first serious contagious disease at a major sporting event. The way in which the wider dispersing attendees were informed at the event should form the basis of management at sporting events in the likelihood of a serious communicable disease.
The Journal of sports medicine and physical fitness 07/2008; 48(2):125-8. · 0.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Highly homologous meningococcal porin A (PorA) proteins induce protective humoral immunity against Neisseria meningitidis group B infection but with large and consistent differences in the levels of serum bactericidal activity achieved. We investigated whether a poor PorA-specific serological outcome is associated with a limited size of the specific B-cell subpopulation involved. The numbers of PorA-specific splenic plasma cells, bone marrow (BM) plasma cells, and splenic memory B cells were compared between mice that received priming and boosting with the weakly immunogenic PorA (P1.7-2,4) protein and those that received priming and boosting with the highly immunogenic PorA (P1.5-1,2-2) protein. Immunoglobulin G (IgG) titers (except at day 42), bactericidal activity, and the avidity of IgG produced against P1.7-2,4 were significantly lower at all time points after priming and boosting than against P1.5-1,2-2. These differences, however, were not associated with a lack of P1.7-2,4-specific plasma cells. Instead, priming with both of the PorAs resulted in the initial expansion of comparable numbers of splenic and BM plasma cells. Moreover, P1.7-2,4-specific BM plasma cells, but not P1.5-1,2-2-specific plasma cells, expanded significantly further after boosting. Likewise, after a relative delay during the priming phase, the splenic P1.7-2,4-specific memory B cells largely outnumbered those specific for P1.5-1,2-2, upon boosting. These trends were observed with different vaccine formulations of the porins. Our results show for the first time that B-cell subpopulations involved in a successfully maturated antibody response against a clinically relevant vaccine antigen are maintained at smaller population sizes than those associated with poor affinity maturation. This bears consequences for the interpretation of immunological memory data in clinical vaccine trials.
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