Number of meningitis epidemics
Current global situation
The epidemic threshold is an operational threshold established in order to differentiate the seasonal case recrudescence from epidemics. Once the weekly attack rate reaches this pre-defined threshold within a given district, and meningococcal meningitis is confirmed, a reactive vaccination campaign should be implemented.
In the 2009 epidemic season, a large-scale outbreak affected the countries of the African Belt, in particular Nigeria. This year, 217 districts crossed the epidemic threshold, 175 of them from Nigeria alone. In 2010, African countries were less affected by meningitis epidemics. Still, 46 districts from Burkina Faso, Chad, Cameroon, Democratic Republic of Congo, Ghana, Niger and Nigeria crossed the epidemic threshold.