Influenza-related hospitalisations in children.

Aim: To describe the disease burden, clinical pattern and outcome of influenza-related hospitalisations in children.

Methods: This is a retrospective study carried out in a regional hospital in Hong Kong. Children hospitalised with established diagnosis of influenza infection from January to June of 2005 were studied. Length of hospitalisation, demographic characteristics, symptoms, clinical diagnosis and complications of influenza infection were analysed.

Results: Influenza A infection accounted for 93.5% of these hospitalisations. Children less than 5 years of age comprised 70% of admission. Highest rate of admission occurred in May and April. One fourth of emergency admission during the study period and over 70% in the peak season was a result of influenza-related illness. Underlying medical disease was observed in 14.6% of children. Mean duration of hospitalisation was 3.0 days. Fever was the commonest presenting symptoms. Fever lasting for 7 days or more was observed in one-fifth of patients. Respiratory tract diseases (upper and lower) were the most frequent non-neurological diagnosis. Febrile convulsion was the complication observed in 27.6% of admission. One patient died as a result of acute necrotising encephalopathy.

Conclusion: Influenza contributed to heavy health-care burden. Mortality was rare but did occur. Hospitalisations occurred in both healthy children and those with underlying chronic illness. Young children played an important role in such hospitalisations. Means to prevent influenza-associated morbidity and mortality especially among young children are needed.