Since 1971, serogroup A and C meningococcal polysaccharide vaccines have been used widely in countries of the African meningitis belt to contain epidemics.
While they have saved many lives by halting epidemics before they run their full course, 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.
The Meningitis Vaccine Project recently developed an affordable serogroup A meningococcal conjugate vaccine for use in Africa, PsA-TT (MenAfriVac). Following successful clinical trials in Africa and India, MenAfriVac is now being rolled out in countries throughout the African meningitis belt and preliminary results suggest that it was effective in preventing serogroup A meningococcal disease and carriage in Burkina Faso.