Human metapneumovirus (hMPV) was recently discovered in children with respiratory tract infection. The aim of this study was to determine the frequency and the clinical manifestation of hMPV infection in Korean children.

From January to December, 2005, we collected throat swabs from 1,098 children who were hospitalized for acute respiratory illness at the Department of Pediatrics, Kwang- Ju Christian Hospital. hMPV was detected by performing reverse transcriptase-polymerase chain reaction (RT-PCR). The medical records of the patients with positive results were retrospectively reviewed.

We detected hMPV in 25 (2.2%) of the 1,098 hospitalized children. The mean age of the hMPV infected children was 2.3 years, and 84% of the illnesses occurred between April and June. The most common diagnoses were pneumonia (60%) and bronchiolitis (20 %). The clinical manifestations included cough, fever, coryza, rale, wheezing and injected throats. Peribronchial infiltration and consolidation were the common chest X-ray findings. Four (16%) of 25 patients with hMPV infection had exacerbation of asthma. Coinfection with other respiratory viruses was found in six children (24%).

hMPV is the cause of an important proportion of acute respiratory tract infection in Korean children. Additional studies are required to define the epidemiology and the extent of disease caused by hMPV and to determine future development of this illness in Korean children.