[efficacy of the polysaccharide vaccine of Neisseria meningitidis group A].
D000293:Adolescent; D001428:Bacterial Vaccines / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008585:Meningitis, Meningococcal / Q000517:prevention & control; D009345:Neisseria meningitidis / Q000276:immunology*; D011134:Polysaccharides / Q000276:immunology*
D001428:Bacterial Vaccines; D011134:Polysaccharides