Meningococcal vaccines

Global control and prevention of meningococcal disease depends on the furth er development of vaccines that overcome the Limitations of the current pol ysaccharide vaccines. Protein-polysaccharide conjugate vaccines likely will address the marginal protective antibody responses and short duration of i mmunity in young children derived from the A, C, T, and W-135 capsular poly saccharides, but they will be expensive to produce and purchase and may not offer a practical solution to the countries with greatest need. In additio n, outer membrane proteins vaccines have been tested extensively in humans and hold some promise in the development of a serogroup B vaccine but are L imited by the antigenic variability of these subcapsular antigens and the r esulting strain-specific protection. Elimination of meningococcal disease l ikely will require a novel approach to vaccine development, ideally incorpo rating a safe and effective antigen or antigens common to all meningococcal serogroups. As a solely human pathogen, however, N. meningitidis has devel oped many teals with which to evade the human immune system and likely will pose a formidable challenge for years to come.