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.

The question that drove the following analysis is “Which intervention is best to use when?”

Intervention interventions that are commonly applied to attack Plasmodium falciparum malaria outbreaks are mass drug administrations (MDA) and mass screen and treat (MSAT). In general, one would prefer to use MSAT in order to save cost and avoid the promotion of drug resistance. But can we put a number on it? Decision makers need numbers, and your simulations have been used to try to quantify the incremental gain from well-designed MSAT campaigns under different settings of background transmission.

For this analysis the outcome measure were estimates of the incremental cost-effectiveness ratio (ICER), using simulation results from malariacontrol.net and cost estimates gleaned from the literature on MSAT campaigns in sub-Saharan Africa. These ICER results were compared to the gain from increased case management or increase the coverage of insecticide-treated net (ITN) in each setting.

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].

At low transmission MSAT was never more cost-effective than scaling up ITN’s or case management. However, once the EIR climbed above 20 or the ITN coverage reached 40%, the cost effectiveness of the MSAT was always nearly that to increasing ITN use.


In all the transmission settings considered, achieving a minimal level of ITN coverage is a best buy. At low transmission, MSAT probably is not worth considering. Instead, MSAT may be suitable at medium to high levels of transmission and at moderate ITN coverage. If undertaken as a burden-reducing intervention, MSAT should be continued indefinitely and should complement, not replace, case management and vector control interventions.

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 without you.
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Mariabeth Silkey
Swiss Tropical and Public Health Institute
http://www.swisstph.ch