Clinical and epidemiological characteristics of influenza-associated respiratory infection in children hospitalized in Shanghai Children's Hospital during 1999-2008 / 中华传染病杂志

ABSTRACT

Objective To study the clinical and the epidemiological features of hospitalized children with influenza virus infection. Methods Two hundred and fifty-three inpatients with laboratory-confirmed influenza virus infection from 1999 to 2008 were reviewed for analyzing the clinical and epidemiological characteristics. Type A and B influenza viruses in the nasopharyngeal aspirates were detected by immunofluorescence assay. Mann-Whitney U test were performed for comparing the median age and the length of hospitalization. Chi-square test was performed for comparing the proportion of patients with fever and cough. Results Among 253 hospitalized children aged between 5 days and 127 months, 182 (71.9%) were boys and 71 (28. 1%) were girls. The median age was 18 months. Fifty-three cases were infants younger than 6 months. 95 cases were children aged between 6 months and 2 years, 85 cases were aged between 2 years and 5 years and 20 cases were older than 5 years. The diagnosis of influenza-related admission included pneumonia (190 cases), bronchitis (49 cases) and upper respiratory tract infection (14 cases). Eleven cases developed febrile convulsion, 6 cases had acute exacerbation of asthma and 3 cases had concomitant viralencephalitis. Twenty-nine cases had basic diseases. Cough and fever were the most common symptoms. Two hundred and thirty-eight cases presenting cough and 209 case presenting fever. Sixty-seven percent (140/209) had high fever with body temperature higher than 39 ℃. The average duration of fever was (5. 0 ±2. 9) days. Fever and cough were both more common in children older than6 months (X2 = 22. 895,P<0. 01; X2 = 16. 992,P<0. 01, respectively). Febrile convulsion occurred in children older than 2 years. Fifteen point five (39/251) developed leukocytopenia. Conclusions Children younger than 5 years old are at high risk of influenza-related hospitalization. We should emphasize influenza vaccination in previously healthy children aged between 6 months and 5 years and children with underlying diseases.