Although global mortality in children younger than 5 years has substantially reduced in the past two decades from more than 12 million deaths in 1990, to 6·9 million in 2011,1 improvements have been inconsistent worldwide. Whereas some countries and regions have reduced child mortality by more than half,2 progress in others has been much slower. Half of all deaths worldwide in children younger than 5 years are concentrated in only five countries: India, Nigeria, the Democratic Republic of the Congo, Pakistan, and China.1 In the past decade, the number of child deaths decreased by 2 million worldwide, with reductions in deaths due to pneumonia and diarrhoea contributing to 40% of the overall reduction.3 Notwithstanding this success, pneumonia diseases still account for 1·3 million deaths and diarrhoeal diseases for 0·7 million deaths, and both are major causes of post-neonatal child deaths.2, 3 Pneumonia is the largest cause of child deaths worldwide. Corresponding reductions in burden of disease and morbidity have been much slower than those for global child mortality. Incidence of diarrhoea has fallen from 3·4 episodes to 2·9 episodes per child-year, and that of pneumonia from 0·29 episodes to 0·23 episodes per child-year between 1990 and 2010.4 Despite such decreases, these disorders are two of the most common reasons for health service attendance and hospital admission, with an estimated 1731 (uncertainty range 1376–2033) million episodes of childhood diarrhoea (uncertainty range 26·6–42·4 million severe episodes) and 120 (60·83–277·03) million episodes of pneumonia (10·03–40·04 million severe episodes) in 2011.5, 6
Pneumonia and diarrhoea deaths are closely associated, with overlapping risk factors such as those related to poverty, undernutrition, poor hygiene, and deprived home environments making children more likely to develop these diseases. Improvements in socioeconomic development with corresponding increases in maternal education, falling fertility rates, and improved living conditions (with reduced crowding) are important contributors to reductions in child mortality.7 However, to reduce childhood pneumonia and diarrhoea, interventions are needed that directly lower disease transmission and severity, and promote access to life-saving treatment once a child becomes sick. Previous reviews8, 9, 10, 11 have shown that increases in coverage with present evidence-based interventions could greatly reduce child mortality and deaths from diarrhoea and pneumonia. However, little consensus exists about approaches to scale up coverage and about delivery strategies to reduce disparities and provide equitable access to marginalised populations.12
Key messages
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Worldwide, pneumonia and diarrhoeal diseases are the two major killers of children younger than 5 years
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Each year, 1·3 million children die from pneumonia and 700 000 from diarrhoea
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Preventive and therapeutic interventions exist that could have a role in reducing the morbidity and mortality burden due to diarrhoea and pneumonia, especially in children younger than 5 years
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Few interventions with wide range of outcomes have been assessed at a sufficient scale
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Interventions with maximum effect include breastfeeding, oral rehydration solution, and community case management
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Despite persistent burden, childhood diarrhoea and pneumonia deaths are avoidable and 15 interventions delivered at scale can prevent most of these avoidable deaths
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Estimates modelled with the Lives Saved Tool show that if the interventions are scaled up by 80% in the 75 Countdown countries, they could save 95% of diarrhoeal and 67% of pneumonia deaths in children younger than 5 years by 2025
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Scaling up of diarrhoea and pneumonia interventions would cost US$6·715 billion, only $2·9 billion more than present levels of spending; costs needed for lives saved calculated on the basis of estimates of projected spending based on historic trend
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Scaling up of these interventions could also ensure equitable delivery of care
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The cost-effectiveness of these interventions in national health systems needs urgent assessment
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With an increasing number of countries deploying community health-worker programmes to reach unreached populations, real opportunities exist to scale-up community advocacy and education programmes and early case detection and management strategies
In this Series paper, we systematically review evidence for the effectiveness of various potential health interventions on morbidity and mortality due to diarrhoea and pneumonia in line with guidelines from the Child Health Epidemiology Reference Group.13 We used a standardised method with criteria from the Child Health and Nutrition Research Initiative (CHNRI) to identify priority areas for research and future interventions. We modelled the potential effect of delivery of these interventions to the 75 high-burden countries that are part of the Countdown to 2015 initiative and assessed the result of scaling-up of interventions on diarrhoea and pneumonia mortality across poverty quintiles in three countries (Bangladesh, Pakistan, and Ethiopia).