human metapneumovirus (MPV) (HMPV)

Last edited 06/2023 and last reviewed 08/2023

Human Metapneumovirus

Human metapneumovirus (MPV) (HMPV)

  • is a respiratory pathogen with worldwide prevalence that produces disease clinically similar to respiratory syncytial virus (RSV)
    • like other members of the Paramyxovirus family, is an enveloped, single-stranded, negative-sense RNA virus
    • is most closely related to avian metapneumovirus type C, the other member of the Metapneumovirus genus, and it is in the Pneumovirinae subfamily with RSV
      • MPV is closely related to avian metapneumovirus subtype C, has circulated for at least 65 years, and nearly every child will be infected with HMPV by the age of 5 (2)

  • is a leading cause of upper and lower respiratory tract infections in children
    • incubation period is believed to be 4 to 9 days
    • shedding occurs for 7 to 14 days
    • virus can remain infectious on fomites for 8 hours, although viral RNA has been isolated from noninfectious particles up to 7 days after inoculation (1)
    • a leading cause of acute respiratory infection, particularly in children, immunocompromised patients, and the elderly (2)
      • children with underlying risk factors including those born prematurely or who have compromised immune systems are at higher risk from MPV (3)
        • as with other viruses, infection may produce incomplete immunity and reinfection can occur at all ages
        • older adults, especially those over 65 or with underlying conditions, can be at particular risk from infection

  • clinical features of MPV-associated disease are similar to those of RSV
    • MPV is an important cause of asthma exacerbations, bronchiolitis, and pneumonia
    • smptoms can include cough, rhinorrhea, sore throat, and fever as well as lower respiratory tract symptoms such as wheezing, difficulty breathing, and hypoxia (2)
    • bacterial superinfection can occur
    • clinical diagnoses most commonly associated with HMPV are bronchiolitis and pneumonia (2)

  • mean age of infection is 6 to 12 months, and nearly all school-age children are seropositive (1)
    • however, infection can recur, likely in part due to impaired CD8+ T-cell response
    • is thought to spread through direct or close contact with infected individuals or objects (fomites) (2)

  • preferred method for diagnosis is reverse transcription-polymerase chain reaction as HMPV is difficult to culture (2)

  • morbidity and mortality are the highest in patients who are premature, are immunosuppressed, or have underlying cardiopulmonary abnormalities (1)

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