Around 90 million children contracted seasonal flu in 2008, causing around one million hospital admissions and as many as 1,11,500 deaths due to the influenza–related pneumonia. About 99% of these deaths were recorded in developing countries.

Senior citizens have long been vulnerable to influenza. However, studies suggest the burden of the disease due to hospital admissions for influenza–associated acute lower respiratory infections (ALRI) in young and very young children is substantial. The first global study on the incidence of influenza–associated ALRI and resultant mortality in children younger than five years was announced by the medical journal Lancet on Friday.

The study by Dr Harish Nair, Centre for Population Health Sciences at University of Edinburgh, concluded that the world recorded 20 million cases of influenza–associated pneumonia, which comprise about 13% or one in eight cases of all paediatric pneumonia globally. Some one million cases of influenza–associated severe pneumonia were estimated, comprising 7% or one in 14 of all severe pediatric pneumonia cases worldwide.

The authors say, “Influenza is the second–most common pathogen identified in children…. Our estimates should inform public health policy and vaccine strategy, especially in developing countries.”

Around 156 million new episodes of ALRI occur worldwide every year, and about 1.56 million children died because of such infections in 2008. Earlier, it was estimated that respiratory syncytial virus is present in 22% of such episodes, making it the most prevalent pathogen in children with ALRI. Also, there were no estimates of global burden of disease from seasonal influenza virus–associated ALRI in young children.

Globally, there is an increasing capacity for laboratory–confirmed diagnosis of influenza infection that led to increased recognition (especially) of severe influenza–related illness in children.