malariacontrol.net: Science update part II: till March 2013

Dear malariacontrol.net member, As promised, here is the second of our three part update on the science of malariacontrol.net. We look at some cost effectiveness analyses that were only possible with your donated cpu cycles. Mass drug administration (MDA), where the entire population is treated with antimalarial drugs, and mass screening and treatment (MSAT), which involves screening the whole population of interest and only treating those who test positive, are two strategies that may have the potential to reduce P. falciparum malaria burden. Although it is more complex to organize, one would prefer to use MSAT in order to avoid over-use of drugs and contributing to the spread of drug resistance. But is MSAT likely to be a good use of resources, and if so, where? Can we put a number on it? Decision makers need comparable information on both the effects and cost of interventions. With your help, simulations have been run to try to quantify the incremental cost per unit health gain from well-designed MSAT campaigns in different health systems and transmission settings. For this analysis the outcome measure was the incremental cost-effectiveness ratio (ICER), expressed as dollars per malaria case averted. Cases averted by MSAT were obtained using simulation results from malariacontrol.net and costs estimated from an economic model using literature on the costs of similar interventions in sub-Saharan Africa. The calculated ICER results were compared to the ICERs of increasing case management or insecticide-treated net (ITN) coverage in each setting. Here by case management we mean doctor’s visits, hospitalization when needed and follow up care. As you can see in the graphic, the incremental savings of each method depended very much the baseline transmission level [ recall last week’s post on EIR]. This figure suggests that MSAT was most cost-effective in settings with a moderate disease burden. The results of your simulations showed that at low transmission MSAT was never more cost-effective than scaling up ITNs or case management and is probably not worth considering. Instead, MSAT may be more suitable at medium to high transmission levels and at moderate ITN coverage. In these settings, the cost-effectiveness of MSAT may be comparable to that of scaling up case management and ITN coverage. In all the transmission settings considered, achieving a minimal level of ITN coverage is a best buy. An interesting finding, and one that merits further investigation, is that achieving 80% ITN coverage across all settings, as per current global malaria strategies, may not be an efficient use of resources, particularly in low-transmission settings. This study suggests that policy-makers may want to consider MSAT to reduce the malaria burden as they choose among interventions for their populations. It also shows how the malaria models can be used to simulate combinations of interventions and generate estimates of their relative cost-effectiveness. We intend to build on this type of work in the future. If you would like more detail on this work, see the paper by Valerie Crowell and others Modelling the cost-effectiveness of mass screening and treatment for reducing Plasmodium falciparum malaria burden. Again, thanks for all your volunteered CPU cycles – we couldn’t do it without you.

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