Meningococcal carriage in the African meningitis belt

Background: In the African meningitis belt, epidemics of meningococcal disease occur periodically, although unpredictably, every few years. These epidemics continue to cause havoc and new efforts to control the disease, through the use of conjugate vaccines, are being made. Conjugate vaccines probably exert their main effect by reducing meningococcal carriage, thus generating herd immunity, but little is known about the epidemiology of meningococcal carriage in Africa. Methods: Prior to the initiation of new studies to address this issue, we have reviewed published studies of meningococcal carriage in the African meningitis belt. Results: The prevalence of meningococcal carriage ranged from 3% to over 30% and the serogroup distribution was variable. Factors influencing carriage include age, contact with a case and the epidemic/ endemic situation. Season and polysaccharide vaccination had little effect on carriage. Few longitudinal carriage studies have been conducted, but these are of great value as the dynamics of carriage within a population is complex. Conclusions: More studies of the pattern of meningococcal carriage in the meningitis belt countries of Africa are needed before widespread