Malaria death rate drops in sub-Saharan Africa
New data published in the New England Journal of Medicine showed that the number of malaria-related deaths declined nearly 60% in sub-Saharan Africa over the past 15 years.
“Substantial progress has been made in reducing the burden of malaria, but a large unfinished agenda remains,” Peter W. Gething, PhD, of the University of Oxford, and colleagues wrote. “The risk of death from malaria is a complicated function of environmental, demographic, and programmatic factors that can result in highly localized patterns of risk.”
The researchers used data from the Malaria Atlas Project and the Global Burden of Disease Study to estimate malaria mortality rates in sub-Saharan Africa from 1990 to 2015. The number of malaria-related deaths significantly increased during the 1990s, peaking in 2003 with an estimated 1,063,000 (95% uncertainty interval, 742,000-1,403,000) deaths. This increase was primarily driven by chloroquine resistance, according to the researchers.
Since 2000, there was a dramatic decrease in estimated malaria deaths across sub-Saharan Africa. Gething and colleagues estimated that the mortality rated decreased 57% (95% uncertainty interval, 46-65), with 12.5 (95% uncertainty interval, 8.3-17) annual deaths per 10,000 population in 2000 and 5.4 (95% uncertainty interval, 3.4-7.9) annual deaths per 10,000 population in 2015. This resulted in a 37% (95% uncertainty interval, 36-39) net decrease of annual deaths from 1,007,000 (95% uncertainty interval, 666,000-1,376,000) in 2000 to 631,000 (95% uncertainty interval, 394,000-914,000) in 2015.
An age-group comparison showed that children aged younger than 5 years accounted for the highest number of deaths. These rates varied considerably across the region from more than 80% at a mortality rate of more than 25 per 10,000 to less than 40% at rates under 1 per 10,000. As malaria transmission declined between 2000 and 2015, deaths decreased in children aged 4 years and younger (78.7% vs. 73.5%) and in those aged 5 to 14 years (6.7% vs. 4.8%). In contrast, the share of annual deaths among individuals aged 15 years and older increased from 14.6% to 21.7%.
Further analysis revealed areas where mortality rates remain high (more than 10 deaths per 10,000) and prevention and treatment efforts such as use of insecticide-treated bed nets and antimalarial drugs remain low (less than 50%). These countries included many parts of Nigeria, Angola and Cameroon, and parts of the Central African Republic, Congo, Guinea and Equatorial Guinea.
Gething and colleagues concluded that the decline in malaria-related deaths in sub-Saharan Africa encourages the “global push” to contain the disease; however, the increase in deaths in the 1990s is a “stark warning” for the future.
“Existing gains and future effects could be reversed if artemisinin resistance is not managed appropriately,” they wrote. “Furthermore, given the central role of insecticide-treated bed nets in reducing the burden of malaria during the past decade, pyrethroid resistance will also need to managed carefully.
“Our estimates further highlight that the residual burden of deaths from malaria remains intolerably large and that the scope for enhanced control is substantial.” – by Stephanie Viguers
Disclosures: Gething and several other authors report receiving grants from the Bill and Melinda Gates Foundation and the Medial Research Council, UK.