Prevalence, clinical presentations and complications among hospitalized children with influenza pneumonia.

Samransamruajkit, R; Hiranrat, T; Chieochansin, T; Sritippayawan, S; Deerojanawong, J; Prapphal, N; Poovorawan, Y

Viral respiratory tract infections are a major cause of hospitalization in children. Influenza is common but often not laboratory proven. We report a prospective study of children admitted with a clinical diagnosis of pneumonia. Infants and children (ages 1 month-15 years) who were hospitalized with community-acquired pneumonia were enrolled in the study. Their nasopharyngeal aspirated samples were analyzed for common respiratory viruses, including influenza virus, by reverse transcription-polymerase chain reaction (RT-PCR) or PCR. Out of 257 patients, we identified 127 (49.4%) cases with respiratory viruses, and influenza was found in 32 of these cases (12.5%). Other common respiratory viruses included respiratory syncytial virus in 42 (16.3%), human metapneumovirus in 24 (9.3%), adenovirus in 17 (6.6%) and parainfluenza virus in 12 (4.7%). The median age of the influenza group was 2 years and 3 months, and 27 (84%) of children in this group were under the age of 5. Asthma was the most common co-morbidity (4/32, 12.5%). Common clinical presentations were fever and cough (100%) with crepitations (90%). The median length of hospitalization was 6 days. Three patients developed respiratory failure, with one mortality (3.1%). One child developed infection-associated hemophagocytic syndrome. Our study demonstrated that young children had a high risk of hospitalization due to influenza pneumonia, which contributed to a significant morbidity.