the majority of private-sector antimalar-
ial drugs are currently received by P. falci-
parum–negative patients, although this esti-
mate is based on malaria prevalence in 2010
and is likely to change over time as malaria
prevalence declines and treatment-seeking
behaviors evolve (details of this calcula-
tion are provided in SM). This overtreat-
ment means both that most febrile patients
are not being treated for the true cause of
their illness and that limited global funding
and drug supplies could be better targeted to
individuals who truly need them.
These averages mask substantial hetero-
geneities (Fig. 1). Of the consumers esti-
mated to have bought an antimalarial med-
icine in the private sector, the fraction who
were likely infected with malaria varied
widely, from <1% in Djibouti and Swaziland
to 56% in Burkina Faso. In eight countries,
more than half of all antimalarials were esti-
mated to be received in the private sector.
Considerable heterogeneity existed within
countries as well as across countries (SM
and fig. S4).
Ultimately, all individuals with fever should
receive appropriate treatment following
accurate diagnosis according to World Health
Organization (WHO) guidelines. Achieving
this aim in the African private sector, how-
ever, will require a diagnostic test for the
estimated 655M febrile individuals who pur-
chase treatment there; only about 50 million
rapid diagnostic tests were delivered globally
in 2010 (2). Resources available for rolling
out diagnostic tests and distributing ACTs
in the private sector are likely to remain
insufficient to reach the significant demand
estimated here in the short term (24). Until
resources are sufficient to properly diagnose
and effectively treat all patients, it will be
necessary to prioritize attempts to improve
the availability of diagnostic tests and effec-
tive malaria drugs so that they will have the
greatest impact on morbidity and mortality.
Interventions like private-sector ACT
subsidies that can improve access to effec-
tive drugs will have the greatest probabil-
ity of each treatment curing a malaria infec-
tion even in the absence of strong diagno-
sis if implemented in those countries on
the right of the figure (Fig. 1), where esti-
mated malaria prevalence in fevers is high-
est. Given the relatively lesser importance
of the private sector for febrile treatment in
countries in the bottom quadrants, private-
sector interventions may be considered a
lower priority in these areas. ACT subsidies
are likely to be most cost-effective if imple-
mented in countries in the upper-right quad-
rant. Although this quadrant includes only
13 out of 39 countries, they tend to have
some of the highest demand for antimalari-
als in the private sector, together account-
ing for 70% of all estimated volumes (461
million annually). Improved accessibility
of diagnostic tests in these countries has
the greatest potential to prevent the unnec-
essary antimalarial treatments, but priori-
tizing deployment to the private sector of
countries in the upper-left quadrant, where
the highest proportions of antimalarials
are currently taken unnecessarily, has the
potential to be the most cost-effective use
of resources available for diagnosis. Intra-
national heterogeneity indicates that some
countries may benefit from prioritization at
a subnational level.
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Acknowledgments: J.M.C. and B.M. received support
from the Bill & Melinda Gates Foundation (BMGF) and the UK
Department for International Development; J.M.C. and A.M. W.
were also supported by UNITAID. A.J. T. received support from
BMGF and National Institute for Allergy and Infectious Diseases, NIH. P. W.G. was funded by the Wellcome Trust.