Respiratory Tract Infections Due to Human Metapneumovirus in Immunocompromised Children

Chu, Helen Y.; Renaud, Christian; Ficken, Elle; Thomson, Blythe; Kuypers, Jane; Englund, Janet A.

Human metapneumovirus (hMPV) is a paramyxovirus first identified in 2001 as a pathogen associated with upper and lower respiratory tract infections in children [1] . Seroprevalence studies show that almost all children acquire infection by 5 years of age, and that frequent reinfections occur through life [2, 3] . The prevalence of hMPV infection among hospitalized children with acute respiratory infection or fever is similar to that of other respiratory viruses. Clinical disease most closely resembles that associated with respiratory syncytial virus infection (RSV), a related paramyxovirus [4] . A prospective cohort study of hMPV revealed a 9.4% seroprevalence in children hospitalized with respiratory tract infections, with 63% of patients requiring supplemental oxygen and 3% requiring intensive care unit (ICU) admission [5] . Lower respiratory tract illnesses (LRTI) caused by hMPV includes bronchiolitis, pneumonia, and croup. hMPV is also associated with acute otitis media, as well as more rarely conjunctivitis, gastroenteritis, and rash [6, 7] . In adults with hematologic malignancy, hMPV is associated with high rates of progression from upper to lower respiratory tract disease and substantial mortality [8, 9] .