Recipients of meningococal polyvalent vaccine are not protected from which serotype of N.meningitidis, with the vaccine available today?
Ans. b (Serotype B) (Ref: Ananthnarayan Microbiology 7th edition, p. 225; Harrison's 18th /, p. 913)Meningococcal polysaccharide vaccines are currently formulated as either bivalent (serogroups AandC) or quadrivalentfserogroups A,C,Y,andW135),with 50 gof each polysaccharide per dose.Local reactions (erythema, induration, and tenderness) may occur in up to 40% of these vaccines, but serious adverse effects (including febrile convulsions in young children) are very rarely reported. In adults, the vaccines are immunogenic, but immunity appears to be relatively short-lived (with antibody levels above baseline for only 2-10 years), and booster doses do not induce a further rise in antibody concentration. The poor immunogenicity of plain polysaccharide vaccines in infancy has been overcome by chemical conjugation of the polysaccharides to a carrier protein (CRM 197, tetanus toxoid, or diphtheria toxoid). Conjugates that contain monovalent serogroup C polysaccharide and quadrivalent vaccines with A, C, Y, and W135 polysaccharides have been developed, as have vaccines including various other antigen combinations, conjugate vaccines overcome the hyporesponsiveness induced by plain polysaccharides by replenishing the memory pool. The reactogenicity of conjugate vaccines is similar to that of plain polysaccharide vaccines.The first quadrivalent conjugate meningococcal vaccine containing A, C, Y, and W135 polysaccharides conjugated to diphtheria toxoid was initially recommended for all children >11 years of age. Adverse Events Reporting System indicated that there might be a short-term increase in the risk of Guillain-Barrie syndrome after immunization with the diphtheria conjugate vaccine.
Serotype A
Serotype B
Serotype C
Serotype Y
Infection