Emergency vaccination against epidemic meningitis in Ghana: implications for the control of meningococcal disease in West Africa

Background Recurrent epidemics of meningococcal disease have been reported throughout the African meningitis belt since description of the disease in 1912, Meningococcal polysaccharide vaccines can effectively prevent disease but the optimum strategy for their use in this setting has been controvers ial. We used data from an outbreak of meningococcal disease in northern Gha na in 1997 to assess the potential effect of different vaccination strategi es. Methods We identified all reported cases of meningococcal meningitis and es timated the number of cases and deaths that could have been prevented by va ccination through use of a simple mathematical model. We then assessed the potential effect of different vaccination strategies and the burden of thes e strategies on the public-health system. Findings In the three affected regions in northern Ghana there were 18 703 cases and 1356 deaths reported between November, 1996, and May, 1997. Vacci nation began in the third week of February and continued to April, reaching 72% of the at-risk population and preventing an estimated 23% of cases and 18% of deaths. A strategy of routine childhood and adult immunisation woul d have prevented 61% of cases had this same rate of vaccine coverage been a chieved and maintained before the epidemic. If vaccination had started afte r the onset of the epidemic in January, as currently advocated by WHO guide lines, a similar proportion (61%) of cases could have been prevented. Interpretation Prevention of epidemics of meningococal disease in west Afri ca will be difficult until long-lasting conjugate vaccines capable of inter rupting transmission of Neisseria meningitidis can be incorporated into rou tine infant-immunisation schedules, Until then, the strategy of surveillanc e and response advocated by WHO is as effective and more practical than a s trategy of routine childhood and adult vaccination with currently available polysaccharide vaccines.