Using weather forecasts to help manage meningitis in the West African Sahel

Understanding and acting on the link between weather and meningitis in the Sahel could help improve vaccinedistribution and save lives. People living there know that meningitis epidemics occur in the dry season and end after thestart of the rainy season. Integrating and analyzing newly available epidemiological and meteorological data quantifiedthis relationship, showing that that the risk of meningitis epidemics climbed from a background level of 2% to amaximum risk of 25% during the dry season. These data also suggested that, of all meteorological variables, relativehumidity has the strongest correlation to cases of meningitis.Weather acts alongside a complex set of environmental, social, and economic drivers, and a complementaryinvestigation of local and regional knowledge, attitudes, and practices suggested several additional interventions tomanage meningitis. These include improved awareness of early meningitis symptoms and vaccinations for farmworkerswho migrate seasonally. An economic survey showed that the cost of a single case of meningitis is 3 times the averageannual household income, underscoring the need for improved vaccination strategy.Using these insights, meteorologists and public health workers developed a tool to guide vaccination decisions. Iterativedevelopment allowed a multinational team of public health officials to use the tool while guiding its refinement anddirected research toward maximum practical use. That meant focusing on predicting areas where high humidity wouldnaturally end epidemics so vaccines could be moved elsewhere. Using this tool and this approach could have preventedan estimated 24,000 cases of meningitis over a 3-yr period.