Background
Globally, one in 10 deaths in children under the age of five years results from diarrhoea, with the majority occurring in sub-Saharan Africa and South East Asia [
1]. Diarrhoea is one of the leading causes of morbidity and mortality in under-five children in South Africa, however the true burden of childhood diarrhoea is not accurately known. Official data from Statistics South Africa estimate that diarrhoea accounts for approximately 20% of under-five deaths [
2], but other sources estimate the burden between 8% [
1] and 13% [
3]. The 2010 General Household Survey (GHS), a nationally representative inquiry into the livelihood of South Africans, showed that there were over 60,000 cases of childhood diarrhoea per month and approximately 9,000 child diarrhoeal deaths in the same year [
2].
Diarrhoea is closely linked to socio-economic status and has the most adverse effects in South Africa’s impoverished communities [
2,
4]. South African children living in poverty are approximately ten times more likely to die from diarrhoea than their more privileged counterparts [
2]. Poor nutritional status, poor environmental conditions, and illnesses such as HIV/AIDS make children more susceptible to severe diarrhoea and dehydration [
4]. Episodes of persistent diarrhoea also worsen a child’s condition and nutritional status due to decreased food intake and nutrient absorption [
4]. In HIV-infected children, persistent diarrhoea is associated with an 11-fold increase in mortality [
5]. More than 50% of South African children who died in 2012 had evidence of HIV infection or exposure, while 60% were undernourished [
6].
UNICEF and WHO have stressed the importance of well-known interventions for reducing the global burden of childhood diarrhoea [
4,
7]. Interventions for diarrhoea prevention include vaccinations against rotavirus, cholera, typhoid and measles; micronutrient supplementation for zinc and vitamin A; prevention and treatment of comorbidities, such as HIV; exclusive breastfeeding promotion and support; adequate nutrition for mothers and children; and interventions for the provision of water, sanitation and hygiene (WASH). Diarrhoea should be treated with oral rehydration solution (ORS), zinc, continued feeding, antibiotics for dysentery, as well as improved care seeking behaviour and improved case management.
Progress is being made towards implementing these interventions. In 2009, South Africa became the only country in sub-Saharan Africa to include the rotavirus vaccine in routine child immunizations. The vaccine, which has been shown to be effective in preventing severe rotavirus diarrhoea [
8], has achieved moderate coverage in South Africa (64%) [
9]. The government revised its breastfeeding policy in 2011 to actively promote exclusive breastfeeding and phase out the distribution of free infant formula to babies born to HIV-positive mothers. South Africa has also achieved the water and sanitation targets for Millennium Development Goal (MDG) 7; over 90% of South Africans have access to a clean public water source and over 70% utilize a latrine or toilet [
10]. However, despite achieving these goals, approximately six million households (46%) do not have access to piped water in their homes and 1.4 million households (11%) still lack access to sanitation services [
11]. Furthermore, the sanitation services in over 3.8 million households (26%) in formal areas do not meet the required standards due to infrastructure deterioration [
11]. Coverage remains low for many of the other recommended interventions, such as hand washing with soap and ORS. Although these health promotion interventions are affordable, there are significant challenges to increasing adoption.
The disparities in access to water and sanitation services, and the poor coverage of essential interventions contribute to the ongoing high prevalence of diarrhoea in the country. This analysis evaluates the potential impact of scaling up coverage of the recommended interventions on under-five diarrhoeal mortality in South Africa between 2014 and 2030. The potential number of lives that could be saved and the resources required for intervention scale up are assessed in order to aid priority setting and budgeting. The results of this analysis could aid South Africa’s plans to reduce child mortality in the post-2015 era.
Discussion
This analysis determines the impact and costs of interventions for the prevention and treatment of diarrhoea in children under-five in South Africa. LiST was used to model the impact of scaling up 13 essential interventions between 2014 and 2030. Three scenarios were implemented for linear coverage scale up from baseline (2014): coverage increased 10 percentage points by 2030; coverage increased 20 percentage points by 2030; and interventions reached full coverage (99%) by 2030.
The results show that scaling up diarrhoeal interventions could contribute significantly to the reduction in child mortality in South Africa. In 2030, diarrhoeal deaths are expected to reduce from an estimated 5,500 in 2014 to 2,800 in scenario one, 1,400 in scenario two and 100 in scenario three. The number of diarrhoea cases is also expected to reduce substantially. Approximately five million cases of diarrhoea can be averted by 2030 if interventions are scaled up to full coverage.
This is the first such analysis and there is no recent South African data with which to compare our results. The GHS conducted by Statistics South Africa in 2010 estimated that there were approximately 60 000 cases of diarrhoea per month in children under-five (about 720 000 per year), and 9,000 diarrhoeal deaths (compared to 5,500 deaths in our model) [
2]. The District Health Information System (DHIS), which records data at health facility level, estimated that the under-five incidence of diarrhoea was 90.3 per 1000 in 2012 (approximately 520 000 cases) [
33]. Though these data sources provide useful information, they may not be entirely representative. The DHIS records the more severe cases of diarrhoea, since a large number of diarrhoea cases are treated at home and/or by traditional healers [
34]. Further, it is worth noting that the landscape in the South African health system has changed significantly since the GHS was undertaken. The rotavirus vaccine was introduced in 2009, fewer babies are born HIV positive, and ARV usage has been scaled up [
35]. There has also been investment in infrastructure, contributing to the provision of safe water and sanitation to more households. These factors may account for the lower projected diarrhoeal deaths in the model in 2014. While it is difficult to verify the results of our analysis in the absence of updated burden of disease data, the recent under-five mortality estimate indicates that there has been an overall improvement in the burden of childhood morbidity and mortality, and this likely includes diarrhoea [
3].
Preventive interventions are crucial. WASH interventions are shown to avert more than 50% of the diarrhoeal deaths, but these also amount to more than 90% of the total intervention costs. Despite many improvements since 1994, South Africa continues to face challenges with implementing home water connections and improved sanitation and there are significant disparities which are not reflected in national statistics. These WASH interventions may thus not be easy to scale up in the timeframe proposed in this analysis. While over 70% of households in South Africa have access to sanitation and over 90% have access to an improved water source, an estimated 12.5% of households in the Eastern Cape province do not have access to any form of sanitation and 14.1% of households in Kwazulu-Natal province have never had access to water [
11]. Considerable effort will be required to ensure these services are delivered to the most marginalised, impoverished and at-risk communities. This will require collaboration with the Department of Health and the Department of Water Affairs, as child mortality and in particular diarrhoeal morbidity and mortality cannot solely be resolved through health systems interventions.
This analysis also shows that breastfeeding could save a large number of child lives if full coverage could be achieved. Exclusively breastfed children are 14 times more likely to survive the first six months of life than those who are not breastfed [
36], yet South Africa has low exclusive breastfeeding rates [
37]. Community peer counselling has been shown to be highly effective in increasing breastfeeding rates in South Africa [
38]. However, there are challenges associated with implementing and maintaining such community-based programmes as they require retention of trained health care workers who are adequately remunerated [
39], and there are entrenched community practices that are difficult to overcome [
40]. Mothers frequently believe that breast milk is insufficient and they give their infants water, gripe water and non-prescription medicines for general health [
40]. This increases the risk of developing diarrhoea from contaminated water and may cause children to become undernourished. When diarrhoea does occur, caregivers most commonly choose to treat their infants at home with ORS [
34] and many prepare the solution incorrectly [
41]. Addressing these behaviour change issues will require considerable effort, community engagement and resources.
The model isolates interventions that impact diarrhoea by maintaining constant coverage of other child health interventions. However, coverage of the other interventions is likely to increase, resulting in a lower burden of under-five mortality by 2030. It is therefore possible that we have overestimated the total number of diarrhoea deaths averted.
This national analysis does not take into account the heterogeneity of intervention coverage and diarrhoeal illness across the 52 districts in South Africa. For example, the institutional diarrhoea case fatality rates in the Eastern Cape are 6.9% compared to the Western Cape at 0.2% [
42]. Furthermore, the paper does not address how increased coverage will be achieved, but the estimated intervention costs can guide policy and budget planning. The additional cost of implementing all 13 interventions will range between US$508 million (US$9 per capita) to US$964 million (US$18 per capita) annually. The eight non-WASH interventions would require an additional investment ranging from US$43 million (less than US$1 per capita) to US$170 million (US$3 per capita) per year. These costs are within South Africa’s allocated health budget (approximately US$14.7 billion in 2014/15) [
43].
The cost projections are likely an underestimate as staff salary increases were not taken into account and infrastructure development is not fully considered. For the WASH interventions, household infrastructure has been estimated, yet broader system infrastructure requirements, such as waste management systems, have not been considered. Furthermore, the model assumes that the health system interventions are delivered at uniformly high quality. This is unlikely given drug shortages, health care worker attitudes and institutional challenges. Significantly more resources are probably required to address such issues.
HIV/AIDS is a major burden in South Africa. In 2008, approximately 3% of children 0–4 years of age were HIV-positive [
44], and this increases the risk of diarrhoeal mortality 11 times [
5]. The model does not however explicitly incorporate the relationship between HIV/AIDS and diarrhoea. This should be included in future analyses.
The long term consequences of diarrhoeal illness have not been incorporated in this analysis. Early childhood diarrhoea is associated with impaired physical and cognitive development. The resulting losses in human potential and economic productivity may have a greater impact than the burden of diarrhoeal mortality [
45]. Furthermore, the full impact of the 13 interventions, on conditions other than diarrhoea, has not been explored. Increased breastfeeding, for example, is associated with a reduction in several childhood illnesses including respiratory infections, gastroenteritis, otitis media and necrotising enterocolitis [
46]. Similarly, other interventions could have benefits in addition to reducing diarrhoea morbidity and mortality. WASH interventions will address neglected tropical diseases which account for significant disability-adjusted life years (DALYs) in low and middle income countries [
47], and have significant impacts not only on health, but also on social and economic development [
48]. The impact and costs of these additional benefits should be taken into account in future research.
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Competing interests
The authors declare that they have no competing interests.
Authors’ contributors
All authors were responsible for the study concept, design, and interpretation of data. LC and JM collected the data, performed the analysis and drafted the manuscript. AT and KH reviewed and provided comments on the manuscript. All authors read and approved the final manuscript.