Comparison of Human Metapneumovirus, Respiratory Syncytial Virus and Influenza A Virus Lower Respiratory Tract Infections in Hospitalized Young Children

Abstract

We compared the clinical and demographic features of children with lower respiratory tract infection (LRI) caused by human metapneumovirus (HMPV), respiratory syncytial virus (RSV) and influenza A virus and sought to determine whether coinfection by HMPV and other respiratory viruses leads to increased disease severity. Nasal wash specimens were prospectively obtained from 516 children hospitalized for LRI during a 1-year period and tested for the presence of HMPV by reverse transcription-polymerase chain reaction and for RSV and influenza A by direct immunofluorescence. HMPV was detected in 68 (13%) patients and was the third most common viral pathogen; 16 of 68 HMPV-positive children (24%) had coinfection with other respiratory viruses (HMPVco). HMPV patients were older than RSV patients (17.6 ± 16.8 months versus 10.5 ± 11.8 months, P = 0.02). HMPV was associated with wheezing and hypoxemia at a rate similar to that of RSV and higher than that of influenza A. Atelectasis was more common among HMPV (40%) than among RSV and influenza patients (13%, P Conclusions: The clinical pattern of HMPV more closely resembles that of RSV than that of influenza A LRI, yet the differences in age, radiographic findings and clinical diagnosis suggest that HMPV pathogenesis may differ from that of RSV.