Estimates of Child Deaths Prevented From Malaria Prevention
Estimates of Child Deaths Prevented From Malaria Prevention
Using the LiST model, this analysis estimated that malaria prevention intervention scale-up over the past decade has prevented 842,800 (uncertainty: 562,800–1,364,600) malaria-caused child deaths across 43 malaria-endemic countries in Africa, compared to a baseline of the year 2000 (Figure 2). Over the entire decade, this represents an 8.2% decrease in the number of malaria-caused child deaths that would have occurred over this period had malaria prevention coverage remained unchanged since 2000 coverage levels. The biggest impact occurred in 2010 with a 24.4% decrease in malaria-caused child deaths compared to what would have happened had malaria prevention interventions not been scaled-up beyond 2000 coverage levels.
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Figure 2.
Number of yearly malaria-caused child deaths prevented by malaria prevention interventions scale-up 2001–2010.
Based on the estimated coverage of household possession of ≥ 1 ITN, it is estimated that scale-up of ITNs prevented 831,100 (uncertainty: 555,800–1,347,200) post-neonatal child malaria deaths across the 43 countries included in this analysis from 2001 through 2010 (Additional file 2). In Nigeria alone, which had an ITN coverage increase from 0 to 45% over this period, 165,700 (uncertainty: 96,800–240,000) post-neonatal child malaria deaths were estimated to have been prevented. Other main contributors to the total post-neonatal child malaria deaths prevented over the past decade, due primarily to substantial ITN scale-up and their large population size, include the Democratic Republic of the Congo, Ethiopia, Mali, Tanzania and Uganda, which total 286,300 (uncertainty: 205,000–429,800) child malaria deaths prevented compared to 2000.
From ITN coverage scale-up 2001–2010, Namibia was estimated to have the largest percentage decline in post-neonatal malaria deaths from 2001–2010 with a 26% decline, while accounting for population growth, followed by Eritrea (24% decline), Togo (21% decline), Mali (21%) and Djibouti (19%) (Figure 3). The five African countries analysed with the largest number of malaria deaths in 2000 had the following percentage declines in post-neonatal malaria deaths from 2001–2010: Nigeria (4% decline), Democratic Republic of Congo (DRC) (9% decline), Uganda (14% decline), Tanzania (3% decline) and Southern Sudan (6% decline). For many countries, the bulk of the decline in malaria-caused mortality occurred in 2010 following rapid ITN scale-up (Figure 3 and Additional file 2 Table 1). Djibouti was estimated to have the largest percentage decline in post-neonatal malaria deaths in 2010 with a 42% decline, followed by Namibia (33% decline), Zimbabwe (29% decline), Togo (26% decline), Madagascar (26% decline), Mali (21%), Senegal (21% decline) and Gabon (21% decline).
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Figure 3.
Percent reduction in malaria-cased child deaths one-59 months.
Across the 32 countries with stable malaria transmission included in this analysis, it is estimated the proportion of pregnant women protected by either IPTp or ITNs in rural areas increased from a mean of 0.7% in the year 2000 to 41.8% in 2010 (Figure 4). It is estimated that from 2001–2010 IPTp and ITNs used during pregnancy prevented a total of 11,700 (uncertainty: 7,000–17,500) child deaths from LBW as a result of malaria in pregnancy, as compared to a baseline year of 2000 (Additional file 2).
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Figure 4.
Proportion of pregnant women in rural areas protected by malaria prevention interventions (IPTp and/or ITNs) across 32 countries in sub-Saharan Africa 2000–2010.
This analysis estimated the median cost of delivery of an ITN to be US$1.64 (Table 1 in Additional file 5). There was some difference between subgroups of delivery systems (median US$1.34 for mass campaigns and US$3.96 for retail distribution). This analysis estimated the median procurement cost of an ITN to be US$5.44. When discounted over a three-year period, one year of ITN ownership was valued at US$1.85. The number of ITNs available in each year in all of the relevant areas of sub-Saharan Africa was estimated to be approximately 130 million, yielding approximately 520 million available net years over the period 2006–2009. Large differences in availability of nets arose from different assumptions of net lifetimes although this did not result in large differences in cost-effectiveness estimates (See Table 2 in Additional file 5). The total discounted cost of all ITNs and their delivery was estimated to be approximately US$1.3 billion. Based on predictions from the LiST model, the number of discounted lives saved using vector control methods over the period (2006–2009) was 475,800, resulting in an estimated US$2,770 per life saved. Lives saved over this period translate into approximate 11.9 million DALYs, resulting in an estimated US$111 per DALY averted. Results were particularly sensitive to variation in the price of an ITN and the number of nets delivered, but the intervention remained very attractive in low-income country settings under all scenarios tested (for the full results of the sensitivity analysis see Additional file 5).
Five possible ITNs scale-up scenarios beyond 2010 were examined (Figure 5). In the case of rapid scale up from estimated 2011 coverage levels to universal coverage (100%) by the end of 2012 and maintained through 2013–2015, it is estimated that 2.77 million post-neonatal child deaths could be prevented for this five-year interval. Achieving such universal coverage of ITNs would result in a 54% reduction in malaria-caused child mortality compared to maintaining 2000 coverage levels, after accounting for population growth; this translates to a decline in the 2015 all-cause < 5 mortality rate by 11.2% due solely to ITNs. With linear scale-up to universal coverage by the end of 2015 from 2011 levels, it is estimated 2.28 million child deaths could be prevented for this five-year interval, as compared to maintaining 2000 coverage levels. If current country scale-up trends 2000–2011 are continued on the same slope through 2012–2015, it is estimated that an additional 1.71 million child deaths could be prevented from 2011–2015, as compared to 2000 coverage levels. Alternatively, if current country coverage is stabilized at 2011 levels, it is estimated that 1.45 million child deaths could be prevented. However, if funding ceased and vector control strategies were no longer available and long-lasting ITN (LLIN) coverage decreased over the five-year interval, assuming LLINs last about three years, as many as 640,400 children would die as a result during this period, compared to maintaining 2011 coverage until 2015.
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Figure 5.
Number of yearly post-neonatal child malaria deaths prevented by ITNs, according to different scale-up scenarios 2011–2015. Continuing current trend was calculated using the slope between the most recent survey estimate and the earliest survey estimate (solid blue line). Achieving 100% coverage by 2015 assumes linear ITN coverage increases to 100% from estimated coverage in 2010 (dotted purple line). Maintaining coverage assumes estimated coverage in 2010 continues through 2015 (dashed orange line). Ceased funding was calculated assuming that ITNs last three years and have a net discard rate of 4% each year (dashed red line).
Results
The 2001–2010 Decade
Using the LiST model, this analysis estimated that malaria prevention intervention scale-up over the past decade has prevented 842,800 (uncertainty: 562,800–1,364,600) malaria-caused child deaths across 43 malaria-endemic countries in Africa, compared to a baseline of the year 2000 (Figure 2). Over the entire decade, this represents an 8.2% decrease in the number of malaria-caused child deaths that would have occurred over this period had malaria prevention coverage remained unchanged since 2000 coverage levels. The biggest impact occurred in 2010 with a 24.4% decrease in malaria-caused child deaths compared to what would have happened had malaria prevention interventions not been scaled-up beyond 2000 coverage levels.
(Enlarge Image)
Figure 2.
Number of yearly malaria-caused child deaths prevented by malaria prevention interventions scale-up 2001–2010.
Based on the estimated coverage of household possession of ≥ 1 ITN, it is estimated that scale-up of ITNs prevented 831,100 (uncertainty: 555,800–1,347,200) post-neonatal child malaria deaths across the 43 countries included in this analysis from 2001 through 2010 (Additional file 2). In Nigeria alone, which had an ITN coverage increase from 0 to 45% over this period, 165,700 (uncertainty: 96,800–240,000) post-neonatal child malaria deaths were estimated to have been prevented. Other main contributors to the total post-neonatal child malaria deaths prevented over the past decade, due primarily to substantial ITN scale-up and their large population size, include the Democratic Republic of the Congo, Ethiopia, Mali, Tanzania and Uganda, which total 286,300 (uncertainty: 205,000–429,800) child malaria deaths prevented compared to 2000.
From ITN coverage scale-up 2001–2010, Namibia was estimated to have the largest percentage decline in post-neonatal malaria deaths from 2001–2010 with a 26% decline, while accounting for population growth, followed by Eritrea (24% decline), Togo (21% decline), Mali (21%) and Djibouti (19%) (Figure 3). The five African countries analysed with the largest number of malaria deaths in 2000 had the following percentage declines in post-neonatal malaria deaths from 2001–2010: Nigeria (4% decline), Democratic Republic of Congo (DRC) (9% decline), Uganda (14% decline), Tanzania (3% decline) and Southern Sudan (6% decline). For many countries, the bulk of the decline in malaria-caused mortality occurred in 2010 following rapid ITN scale-up (Figure 3 and Additional file 2 Table 1). Djibouti was estimated to have the largest percentage decline in post-neonatal malaria deaths in 2010 with a 42% decline, followed by Namibia (33% decline), Zimbabwe (29% decline), Togo (26% decline), Madagascar (26% decline), Mali (21%), Senegal (21% decline) and Gabon (21% decline).
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Figure 3.
Percent reduction in malaria-cased child deaths one-59 months.
Across the 32 countries with stable malaria transmission included in this analysis, it is estimated the proportion of pregnant women protected by either IPTp or ITNs in rural areas increased from a mean of 0.7% in the year 2000 to 41.8% in 2010 (Figure 4). It is estimated that from 2001–2010 IPTp and ITNs used during pregnancy prevented a total of 11,700 (uncertainty: 7,000–17,500) child deaths from LBW as a result of malaria in pregnancy, as compared to a baseline year of 2000 (Additional file 2).
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Figure 4.
Proportion of pregnant women in rural areas protected by malaria prevention interventions (IPTp and/or ITNs) across 32 countries in sub-Saharan Africa 2000–2010.
Cost Effectiveness 2006–2009
This analysis estimated the median cost of delivery of an ITN to be US$1.64 (Table 1 in Additional file 5). There was some difference between subgroups of delivery systems (median US$1.34 for mass campaigns and US$3.96 for retail distribution). This analysis estimated the median procurement cost of an ITN to be US$5.44. When discounted over a three-year period, one year of ITN ownership was valued at US$1.85. The number of ITNs available in each year in all of the relevant areas of sub-Saharan Africa was estimated to be approximately 130 million, yielding approximately 520 million available net years over the period 2006–2009. Large differences in availability of nets arose from different assumptions of net lifetimes although this did not result in large differences in cost-effectiveness estimates (See Table 2 in Additional file 5). The total discounted cost of all ITNs and their delivery was estimated to be approximately US$1.3 billion. Based on predictions from the LiST model, the number of discounted lives saved using vector control methods over the period (2006–2009) was 475,800, resulting in an estimated US$2,770 per life saved. Lives saved over this period translate into approximate 11.9 million DALYs, resulting in an estimated US$111 per DALY averted. Results were particularly sensitive to variation in the price of an ITN and the number of nets delivered, but the intervention remained very attractive in low-income country settings under all scenarios tested (for the full results of the sensitivity analysis see Additional file 5).
Estimates for 2011–2015
Five possible ITNs scale-up scenarios beyond 2010 were examined (Figure 5). In the case of rapid scale up from estimated 2011 coverage levels to universal coverage (100%) by the end of 2012 and maintained through 2013–2015, it is estimated that 2.77 million post-neonatal child deaths could be prevented for this five-year interval. Achieving such universal coverage of ITNs would result in a 54% reduction in malaria-caused child mortality compared to maintaining 2000 coverage levels, after accounting for population growth; this translates to a decline in the 2015 all-cause < 5 mortality rate by 11.2% due solely to ITNs. With linear scale-up to universal coverage by the end of 2015 from 2011 levels, it is estimated 2.28 million child deaths could be prevented for this five-year interval, as compared to maintaining 2000 coverage levels. If current country scale-up trends 2000–2011 are continued on the same slope through 2012–2015, it is estimated that an additional 1.71 million child deaths could be prevented from 2011–2015, as compared to 2000 coverage levels. Alternatively, if current country coverage is stabilized at 2011 levels, it is estimated that 1.45 million child deaths could be prevented. However, if funding ceased and vector control strategies were no longer available and long-lasting ITN (LLIN) coverage decreased over the five-year interval, assuming LLINs last about three years, as many as 640,400 children would die as a result during this period, compared to maintaining 2011 coverage until 2015.
(Enlarge Image)
Figure 5.
Number of yearly post-neonatal child malaria deaths prevented by ITNs, according to different scale-up scenarios 2011–2015. Continuing current trend was calculated using the slope between the most recent survey estimate and the earliest survey estimate (solid blue line). Achieving 100% coverage by 2015 assumes linear ITN coverage increases to 100% from estimated coverage in 2010 (dotted purple line). Maintaining coverage assumes estimated coverage in 2010 continues through 2015 (dashed orange line). Ceased funding was calculated assuming that ITNs last three years and have a net discard rate of 4% each year (dashed red line).
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