Varying clinical pictures among young children with influenza virus type A infections

The clinical course of Influenza type A virus infections in 47 hospitalized children aged 0-9 years was assessed retrospectively. The infection was diagnosed by demonstration of the virus in the nasopharyngeal secretion during the acute phase of the illness. Out of 21 Influenza A strains in which the subtype was determined, one was found to be H1- and 20 were H3-subtype. Lower respiratory tract disease was the main diagnosis in 21 children, 16 of whom had pneumonia; 14 of these patients were under three years of age. Gastro-intestinal symptoms occurred in 40% of the children over three years of age. Eight patients had febrile convulsions, a girl aged nine years had double vision and vertigo and a female infant aged two months had periodic apnoea and bradycardia. The reasons for hospitalization were febrile convulsions, abdominal pain, lower respiratory tract symptoms and high pyrexia.