Comparison of cost-effectiveness of preventive and reactive mass immunization campaigns against meningococcal meningitis in West Africa: a theoretical modeling analysis

For epidemic meningitis control in sub-Saharan Africa, the World Health Org anization recommends a strategy of emergency vaccination with meningococcal A + C polysaccharide vaccine when epidemic thresholds are exceeded. An alt ernative strategy for areas without effective surveillance systems is mass preventive campaigns before outbreaks occur. A model was formulated to simu late epidemics and to compare the cost-effectiveness of these two strategic s for the district of Matam, Senegal, where an actual preventive campaign w as performed during 1997. The preventive strategy prevented 59% of the case s compared to 49% for the emergency strategy. The cost per case prevented w as US$59 for the preventive strategy and US$133 for the reactive strategy, and the preventive strategy saved US$0.20 per habitant. Preventive meningoc occal vaccination through mass campaigns prevented more outcomes at a lower cost, provided that the occurrence of an epidemic could br predicted withi n 3 years and that the vaccination coverage rates for the preventive and st andard strategies were > 70% and < 94%, respectively. Sub-Saharan African c ountries without effective surveillance systems should consider mass preven tive campaigns while awaiting an affordable conjugate vaccine. (C) 2001 Els evier Science Ltd. All rights reserved.