Meningococcal vaccines.

Neisseria meningitidis is one of the leading infectious causes of death in children under five years old in industrialized countries, and most cases can be attributed to five disease-causing serogroups: A, B, C, Y and W135. Meningococcal vaccine development began in the 1930s with killed whole-cell and exotoxin vaccines, but widespread use of polysaccharide vaccines did not begin until the 1970s. Serogroup A, C, Y and W135 polysaccharides are all included in vaccines for travellers, other high risk groups and control of outbreaks, but have limited immunogenicity and effficacy in childhood. Protein-polysaccharide conjugate vaccines overcome this problem and offer the possibility of protection in early childhoodfrom serogroup A, C, Y and W135. An effective serogroup B vaccine remains elusive and the greatest challengefor vaccine developers.