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Pneumonia – the most important paediatric problem in the world

The poor profile of pneumonia is a great mystery of modern paediatrics. It is beyond doubt that this is the most important paediatric problem in the world. While the burden of disease models that have become so fashionable in recent years produce wildly different estimates for the numbers of pneumonia deaths by country, all are agreed that pneumonia is the biggest cause of child death outside the neonatal period globally, and at country level it is the leading cause in almost all developing countries. Even in the malarious areas of central Africa the numbers of pneumonia deaths are similar to the numbers of malaria deaths. 

So open a copy of any textbook of paediatrics and look up pneumonia. There are no national or international conferences on childhood pneumonia. Management of pneumonia in most parts of the world has changed very little in the past 30 years, despite unacceptably high case fatality rates in many areas. The introduction and rational use of oxygen, due in no small part to Dr Trevor Duke of The Royal Children’s Hospital, is the main improvement we have seen over the past two decades. Prevention has received a boost over the past decade with the introduction of pneumococcal conjugate vaccines into most African countries. Introduction in Asia has barely started, largely because of lack of information about the causes of pneumonia in Asia. 

This brings me to my main point. Despite the overwhelming importance of childhood pneumonia in the world, the global research effort has been miserable. Consider what is not known:

Aetiology 

A handful of studies in the 1980s and 1990s showed that in the countries studied (mainly Gambia and Papua New Guinea), two bacterial species caused most severe cases – pneumococcus and Haemophilus influenzae. The importance of these has been proven in vaccine studies in Africa, but there are few data from Asia. Even in India where 200,000-400,000 children (according to which model one reads) die every year from pneumonia, there are paediatricians arguing that Hib and pneumococcal vaccines have no place, as there is no evidence that they are important causes of pneumonia in Indian children. The role of Staph aureus as a cause of severe pneumonia remains unclear and we are still surprised to find many children with undiagnosed tuberculosis among pneumonia cases.

Pathophysiology

There have been no systematic studies of the pathophysiology of pneumonia in children. Textbooks explain hypoxia in pneumonia as due to ventilation/perfusion mismatch, yet most children respond quickly to oxygen, apparently contradicting that explanation. Cardiac failure might be an important factor in mortality, but this has never been studied.

Management

Recently, on the basis of some studies of not-very-severe pneumonia cases in Pakistan, WHO revised global management guidelines to recommend that many pneumonia cases that had previously been managed in hospital should be managed in the community. The evidence base for this decision was very weak, and included no studies from Africa where the risk of pneumonia death in childhood is highest. The consequences of this recommendation are unknown.

Repeatedly we find the same problem. Lack of research leads to poor public policy. So whose fault is this? Recently the Gates Foundation took on childhood pneumonia and supported a large, multi-country study of pneumonia aetiology. Unfortunately early indications are that the study (PERCH) may not have taken the field forward, while the sum of money they put into the project appears to have dissuaded other funding agencies from supporting work in the field. In my view responsibility for the global lack of interest in pneumonia lies with the global paediatric community. If the world does not pay attention to the biggest paediatric problem in the world, who else can we blame?

Professor Kim Mulholland is one of the world's most prolific childhood pneumonia researchers. He has spent much of his career working in the developing world, particularly Sudan and Gambia, and more recently in Fiji and Vietnam. Read more about his research below:

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