Progress in Tackling Malaria
Jan. 28, 2014, 4:11 p.m.
Since we last featured malaria in an Editorial nearly 4 years ago, encouraging progress has been made in limiting the burden of illness and death caused by the disease. According to the World Malaria Report 2013, published on Dec 11, there were in 2012 an estimated 207 million cases of malaria (95% uncertainty interval 135 million to 287 million), which led to about 627 000 deaths (473 000—789 000). By comparison, in 2008 there were an estimated 225 million malaria cases and 747 000 deaths (numbers revised downwards from those we quoted 4 years ago). In 2012, 84% of malaria cases and 92% of deaths occurred in sub-Saharan Africa. However, this view of global progress encompasses a more complex pattern of national and regional variations. Moreover, funding shortfalls threaten control programmes.
Since 2000, substantially increased funding and political commitment to malaria control have accompanied a fall in malaria incidence of 29% and in malaria-related mortality of 45%. Indeed, 3·3 million lives are estimated to have been saved since the beginning of the millennium. Most deaths (483 000) occur in children less than 5 years old, and the malaria mortality rate in this group has halved since 2000. Nevertheless, in 2012 malaria transmission was ongoing in 97 countries and 3·4 billion people are estimated to be at risk. In her foreword to the World Malaria Report, Margaret Chan, Director-General of WHO, notes that 59 countries are meeting the Millennium Development Goal of reversing the incidence of malaria, and 52 countries are on track to reduce incidence by 75% between 2000 and 2015. But these 52 countries accounted for just 8 million (4%) of the estimated 226 million cases in 2000. High-burden countries in terms of cases and deaths are all—with the exception of India—in sub-Saharan Africa, and in many of these surveillance data are insufficient to assess malaria trends.
Funding for malaria control provided by international donors, which was less than US$100 million in 2000, had increased to $1·94 billion by 2012. Although domestic financing added $522 million, the combined total of around $2·5 billion is well short of the annual $5·1 billion estimated to be necessary for malaria control and elimination activities in the 2008 Global Malaria Action Plan. Projected funding of $2·85 billion for 2014—16 remains insufficient. In December, donors pledged $12 billion to the Global Fund to Fight AIDS, Tuberculosis and Malaria for 2014—16, an increase of 30% over the previous 3 year period, although it is not yet clear how this commitment will affect funding for malaria.
The report reveals that progress in providing insecticide-treated bednets faltered because of funding problems. In sub-Saharan Africa, 150 million nets need to be delivered each year to protect people from mosquito vectors of the malaria parasite; however, only 70 million were delivered in 2012. This situation improved in 2013 with 136 million nets delivered, and 200 million nets have been financed by donors for 2014. 42% of people in sub-Saharan Africa had access to a bednet in their household in 2013. Only 135 million people (4% of the population at risk) were protected by indoor residual spraying of insecticide in 2012, perhaps because of a switch to using more costly non-pyrethroid insecticides when budgets for spraying are static.
There is scope also for improving access to intermittent preventive treatment against malaria during pregnancy, with 64% of women attending antenatal clinics in the WHO Africa region receiving at least one dose of chemoprevention, 38% two doses, and 23% three doses.
Availability of rapid diagnostic tests for malaria limits treatment being given on the basis of signs and symptoms alone. Encouragingly, sales of such tests increased from 88 million in 2010 to 205 million in 2012. Delivery of artemisinin-based combination therapies (ACTs), the recommended treatment for the great majority (91%) of malaria infections caused byPlasmodium falciparum, increased from 11 million courses in 2005 to 331 million in 2012. Emergence of reduced susceptibility to artemisinins in southeast Asia is a concern. Currently, ACTs remain almost universally effective, but it is essential that countries affected by malaria do regular therapeutic efficacy studies.
Vaccination may become a factor in malaria control in the future; however, for the time being, experience shows that investment in the well established tools is effective and should be increased to benefit all people at risk of malaria and to progress towards an eventual goal of elimination.