Modeling the cost-effectiveness of mass screening and treatment for reducing Plasmodium falciparum malaria burden

Abstract

Background: Past experience and modelling suggest that, in most cases,mass treatment strategies are not likely to succeed in interruptingPlasmodium falciparum malaria transmission. However, this does notpreclude their use to reduce disease burden. Mass screening andtreatment (MSAT) is preferred to mass drug administration (MDA), as thelatter involves massive over-use of drugs. This paper reportssimulations of the incremental cost-effectiveness of well-conducted MSATcampaigns as a strategy for P. falciparum malaria disease-burdenreduction in settings with varying receptivity (ability of the combinedvector population in a setting to transmit disease) and access to casemanagement.Methods: MSAT incremental cost-effectiveness ratios (ICERs) wereestimated in different sub-Saharan African settings using simulationmodels of the dynamics of malaria and a literature-based MSAT costestimate. Imported infections were simulated at a rate of two per 1,000population per annum. These estimates were compared to the ICERs ofscaling up case management or insecticide-treated net (ITN) coverage ineach baseline health system, in the absence of MSAT.Results: MSAT averted most episodes, and resulted in the lowest ICERs,in settings with a moderate level of disease burden. At a lowpre-intervention entomological inoculation rate (EIR) of two infectiousbites per adult per annum (IBPAPA) MSAT was never more cost-effectivethan scaling up ITNs or case management coverage. However, atpre-intervention entomological inoculation rates (EIRs) of 20 and 50IBPAPA and ITN coverage levels of 40 or 60%, respectively, the ICER ofMSAT was similar to that of scaling up ITN coverage further.Conclusions: In all the transmission settings considered, achieving aminimal level of ITN coverage is a ``best buy{''}. At low transmission,MSAT probably is not worth considering. Instead, MSAT may be suitable atmedium to high levels of transmission and at moderate ITN coverage. Ifundertaken as a burden-reducing intervention, MSAT should be continuedindefinitely and should complement, not replace, case management andvector control interventions.