Since 1971, serogroup A + C meningococcal polysaccharide vaccines. based on the polysaccharide capsules of the meningococcus, have been used widely in countries of the African meningitis belt to contain epidemics.

While they have probably saved many lives by halting epidemics before they have reached their peak, their widespread use has not reduced the frequency of epidemics. The immunity to infection provided by polysaccharide vaccines is short, especially in young children, and they do not generally prevent meningococcal carriage and so cannot interrupt transmission.

Polysaccharide/protein conjugate vaccines overcome some of the limitations of polysaccharide vaccines. They induce immunological memory and prevent carriage and so can interrupt transmission.

In the UK and elsewhere in Europe, widespread deployment of serogroup C meningococcal conjugate vaccines has been highly successful in preventing serogroup C meningococcal disease.  An affordable serogroup A meningococcal conjugate vaccine for use in Africa is now being developed, and is currently undergoing clinical trials in Africa and India.