Author Affiliation: Expanded Programme on Immunization, World Health Organization, Geneva, Switzerland.
Neisseria meningitidis can cause rapid onset
of meningitis and sepsis, leading to death or permanent disability. Meningococcal
disease occurs globally, and while the largest outbreaks and preponderance
of mortality and morbidity occur in the developing world, the disease continues
to strike the young in developed countries.
The N meningitidis organism is usually classified
in terms of serogroup, referring to the antigenic properties of the capsular
polysaccharide. Most disease in the developed world is caused by organisms
of serogroups B, C, Y, and W135 while serogroup A organisms cause the bulk
of disease in the developing world.1 Vaccines
prepared with polysaccharides from A, C, Y, and W135 organisms are safe, immunogenic,
and have been shown to be effective, particularly in providing short-term
and medium-term protection against outbreaks caused by serogroups A and C
organisms.2 Serogroup B polysaccharide is not
immunogenic. Preparation of vaccines from serogroup B proteins has been problematic,
and efficacy of these products in young children, those at highest risk of
disease, is disputed.2 Thus, prevention of
meningococcal disease through vaccination has relied on the use of the polysaccharide
vaccines that are available for some but not all strains.
Wenger J. Toward Control of Meningococcal DiseaseReducing Risk in College Students. JAMA. 2001;286(6):720-721. doi:10.1001/jama.286.6.720