Clinical analysis of the pediatric inpatients with lower respiratory tract infection due to human metapneumovirus.

Human metapneumovirus (hMPV) is known as one of popular agents of acute respiratory infection in children. We reviewed the patients' background, result of initial blood test, bacterial culture, chest X-ray and clinical features of hospitalized children with lower respiratory tract infections caused by hMPV from March 2014 to February 2015 and compared them with the infections due to respiratory syncytial virus (RSV) and other causative agents. Of 419 patients tested by rapid virus antigen tests, 35 were positive for hMPV, 145 were positive for RSV, and 239 were negative for both viruses. Most of hMPV infections occurred between March and June, and 72% of households of hMPV-positive children got sick. hMPV-positive children did not have any specific symptoms such as wheezing in RSV- positive children. However, many of them were admitted due to prolonged high fever and/or ill appearance despite of no respiratory distress. Although it is said that hMPV-positive children admitted to hospitals tend to have pneumonia, the ratio of children'with pneumonia in this study was less than 60%.