The significant progress made against child mortality around the world over the last two decades is frequently cited as one of the biggest success stories of international development.
Much more remains to be done, but it’s worth looking at what we know – and don’t know – about this propitious decline in child deaths.
Between 1990 and 2010, death rates among children under 5 decreased by 43% in sub-Saharan Africa, according to the Global Burden of Disease Study 2010 (GBD 2010). The screen grab below shows how deaths from different diseases and injuries in this age group decreased over time. Three major categories of diseases played key roles in driving this decline: diarrhea, lower respiratory infections, and other infectious diseases; neonatal disorders; and neglected tropical diseases and malaria.
Death rates in children under 5 years, sub-Saharan Africa, 1990-2010
What interventions deserve credit for these declines? GBD researchers have not yet done a formal study to pinpoint all the reasons for the drop in child mortality, but a deep dive into the data can reveal likely causes.
The next screen grab illustrates the different diseases that make up the category diarrhea, lower respiratory infections, and other infectious diseases. Increases in vaccination coverage likely explain the drop in death rates from diseases such as measles, tetanus, and meningitis. Diarrhea death rates also declined substantially.
“Declines in deaths from diarrheal diseases in children in sub-Saharan Africa are probably due to factors including better treatment of these diseases and increased skills of health workers,” said Mohsen Naghavi, a lead author on the GBD study. “Rising maternal education and better sanitation are additional factors that are likely contributing to these declines.”
Death rates in children under 5 years from diarrhea, lower respiratory infections, and other infectious diseases, sub-Saharan Africa, 1990-2010
In a paper published in 2010, GBD author Professor Emmanuela Gakidou and colleagues found that more than half of the reduction in child deaths worldwide was due to increased maternal education.
The screen grab below shows trends in malaria and neglected tropical disease death rates among children under five in sub-Saharan Africa. Malaria death rates increased until the year 2000, then started to drop.
Death rates in children under 5 years from malaria and neglected tropical diseases, sub-Saharan Africa, 1990-2010
The declines in malaria deaths occurred at the same time that malaria interventions across sub-Saharan Africa were scaling up. As an example, the maps below show how coverage of insecticide-treated bed nets increased dramatically after 2005.
Annual coverage of insecticide-treated nets at the national level in 44 African countries, 2003-2008
Source: Flaxman AD, Fullman N, Otten MW, Menon M, et al. (2010) Rapid Scaling Up of Insecticide-Treated Bed Net Coverage in Africa and Its Relationship with Development Assistance for Health: A Systematic Synthesis of Supply, Distribution, and Household Survey Data. PLoS Medicine. 7(8): e1000328. doi:10.1371/journal.pmed.1000328
In addition to exploring possible reasons why child mortality is declining in sub-Saharan Africa, it’s also important to explain how we know that it’s declining. Child mortality data in many sub-Saharan African countries are weaker than they are in wealthier regions. A major challenge for measuring child mortality in sub-Saharan Africa is the lack of or incompleteness of vital registration systems that record deaths through death certificates.
Compare the two illustrations below that show child mortality data sources for El Salvador and Kenya. GBD researchers used data from El Salvador’s vital registration system as well as censuses and household surveys, as shown below in a screen grab from IHME’s mortality visualization tool. However, GBD researchers were only able to use household surveys and censuses to estimate child mortality in Kenya.
Since the available data were stronger in El Salvador than in Kenya, the GBD estimates of child mortality are more uncertain for Kenya than they are for El Salvador (indicated by pink shading). In El Salvador in 2010, child mortality could be as low as 266 per 100,000 or as high as 362 per 100,000. In Kenya, the range for child mortality is substantially wider and could be anywhere from 1,184 to 1,514 per 100,000.
Data sources and estimates of under-5 child mortality in El Salvador and Kenya, 1990-2010
The next screen grab shows the estimates and the uncertainty surrounding the estimates (vertical bars) of under-5 deaths in sub-Saharan Africa.
Uncertainty surrounding death rates in children under 5 years, sub-Saharan Africa, 1990-2010
Despite the higher uncertainty surrounding estimates of child death rates in sub-Saharan Africa compared to other regions, GBD researchers are certain that they are declining. In fact, looking back at estimates of child mortality from researchers at the Institute for Health Metrics and Evaluation, UNICEF, and the most recent GBD study reveals that each updated estimate has been progressively lower than previous ones (view Figure 7 in this paper, which is available for free with registration). In each update, scientists obtain more data and apply more advanced methods. When new child mortality estimates are released as part of the GBD Study 2013, it will be enlightening to see what the new data and improved methods reveal.
Katie Leach-Kemon, a weekly contributor of global health visual information posts for Humanosphere, is a policy translation specialist from the University of Washington’s Institute for Health Metrics and Evaluation.