Human Metapneumovirus (HMPV): Advances in Diagnosis, Molecular Epidemiology, and Clinical Impact of an Underrecognized Respiratory Virus.

Human metapneumovirus or HMPV is an important respiratory pathogen of public health significance that primarily affects the immunocompromised, the very old, and young infants. However, recent studies have long since dispelled the idea that healthy adults are not at risk for serious sequelae, though it seems that HMPV has a particular affinity to infect children rather than adults. HMPV was first identified in 2001 and is implicated in a range of respiratory illnesses, from less severe upper respiratory infections to more severe pneumonia. This review compiles the recent literature on the epidemiology, molecular virology, and clinical characteristics of HMPV with an emphasis on, importantly, the virus's significant contribution to respiratory morbidity and the requirement for better diagnostic capabilities and public health measures against this very much underappreciated viral pathogen.