Date Published: November 21, 2017
Publisher: Public Library of Science
Author(s): Peter Winskill, Hannah C. Slater, Jamie T. Griffin, Azra C. Ghani, Patrick G. T. Walker, Lorenz von Seidlein
Abstract: BackgroundAlthough significant progress has been made in reducing malaria transmission globally in recent years, a large number of people remain at risk and hence the gains made are fragile. Funding lags well behind amounts needed to protect all those at risk and ongoing contributions from major donors, such as the President’s Malaria Initiative (PMI), are vital to maintain progress and pursue further reductions in burden. We use a mathematical modelling approach to estimate the impact of PMI investments to date in reducing malaria burden and to explore the potential negative impact on malaria burden should a proposed 44% reduction in PMI funding occur.Methods and findingsWe combined an established mathematical model of Plasmodium falciparum transmission dynamics with epidemiological, intervention, and PMI-financing data to estimate the contribution PMI has made to malaria control via funding for long-lasting insecticide treated nets (LLINs), indoor residual spraying (IRS), and artemisinin combination therapies (ACTs). We estimate that PMI has prevented 185 million (95% CrI: 138 million, 230 million) malaria cases and saved 940,049 (95% CrI: 545,228, 1.4 million) lives since 2005. If funding is maintained, PMI-funded interventions are estimated to avert a further 162 million (95% CrI: 116 million, 194 million) cases, saving a further 692,589 (95% CrI: 392,694, 955,653) lives between 2017 and 2020. With an estimate of US$94 (95% CrI: US$51, US$166) per Disability Adjusted Life Year (DALY) averted, PMI-funded interventions are highly cost-effective. We also demonstrate the further impact of this investment by reducing caseloads on health systems. If a 44% reduction in PMI funding were to occur, we predict that this loss of direct aid could result in an additional 67 million (95% CrI: 49 million, 82 million) cases and 290,649 (95% CrI: 167,208, 395,263) deaths between 2017 and 2020. We have not modelled indirect impacts of PMI funding (such as health systems strengthening) in this analysis.ConclusionsOur model estimates that PMI has played a significant role in reducing malaria cases and deaths since its inception. Reductions in funding to PMI could lead to large increases in the number of malaria cases and deaths, damaging global goals of malaria control and elimination.
Partial Text: Unprecedented effort has seen the global burden of malaria halve since the turn of the 21st century due to the widespread distribution of highly effective preventative interventions such as long-lasting insecticide treated nets (LLINs) and indoor residual spraying (IRS) and the provision of highly efficacious treatment with artemisinin combination therapies (ACTs) . However, funding for malaria control has plateaued, falling well behind what is necessary to expand protection to all those in need [2,3]. The continued high level of support for foreign aid contributions in a fluid global political landscape is not guaranteed and gains in malaria control can be fragile if intervention coverage, which is largely dependent on donor funding, is not maintained .
We linked data on PMI financing, historical intervention coverage, and the underlying epidemiology in modelled countries with estimates of the potential effect of reduction in PMI funding on the coverage of interventions nationally. These estimates were then used as inputs for an established transmission model of P. falciparum malaria [11,12] to project the impact of reductions in funding on cases, deaths, and Disability Adjusted Life Years (DALYs) (Fig 1).
To date, PMI has allocated over US$5 billion to 19 PMI focus countries in sub-Saharan Africa as well as the GMS  (Fig 2). We attribute increases in coverage of 8.13% for LLINs, 4.18% for IRS, and 12.9% for ACTs to PMI funding in supported countries in 2015. We estimate that in the 12 years since its inception, PMI has prevented 185 million malaria cases (95% CrI: 138 million, 230 million) (Fig 3A) and saved 940,049 lives (95% CrI: 545,228, 1.4 million) (Fig 3B), the majority of which (77%, 95% CrI: 75%, 81%) would have occurred in children under the age of 5. In sub-Saharan Africa, we estimate that PMI investment has led to an 11.6% (95% CrI: 9.5%, 13.0%) reduction in incidence and an 18.3% (95% CrI: 16.3%, 20.4%) reduction in under-5 malaria-mortality rates in 2015. We estimate the biggest impact in terms of absolute cases averted to have occurred in long-term supported countries with the highest burden. For example, Nigeria, the country with the highest burden globally , has received approximately US$345 million from PMI since 2010 , leading to an estimated 13.8 million cases (95% CrI: 8.7 million, 17.0 million) averted and 128,861 lives (95% CrI: 75,852, 200,075) saved. Angola has benefitted from continuous support since 2005, seeing investments totalling US$248 million dollars , leading to an estimated 8.7 million cases (95% CrI: 6.3 million, 10.4 million) averted and 43,752 lives (95% CrI: 24,946, 61,433) saved.
Here, we have produced modelled estimates of the programme-wide effectiveness of PMI in terms of the impact it has had upon malaria morbidity and mortality since its inception in 2005. We estimate that PMI has averted 185 million cases and 940,049 deaths to date. If funding for PMI is maintained, we predict that a further 162 million cases and 692,589 deaths could be averted over the next 4 years, compared to no PMI funding. However, in comparison to continued full PMI support, a 44% cut in the PMI budget, as indicated in the May 2017 Congressional Budget Justification, could result in an additional 67 million cases and 290,649 deaths in the next 4 years.