Human Metapneumovirus (HMPV): Epidemiology, Pathogenesis, Clinical Impact, and Advances in Diagnosis, Treatment, and Vaccine Development

The Human metapneumovirus (HMPV) is an important human pathogen that predominantly causes acute respiratory tract infections (ARTIs) in infants, the elderly, and immunocompromised hosts. HMPV is also a member of the Paramyxoviridae family and shares several features with the respiratory syncytial virus, including main genetic similarity, seasonality, modes of human‐to‐human transmission, and immune evasion. The virus has a single-stranded, negative-sense RNA genome with nine open reading frames (ORFs) that encode key proteins essential for viral replication, immune evasion, and pathogenic mechanisms. HMPV is highly contagious and spreads through respiratory droplets and direct contact, with peak infections during late winter and early spring. The disease spectrum ranges from mild upper respiratory symptoms to bronchiolitis and pneumonia in the lower respiratory tract. The virus’s capacity for suppressing type I interferon responses accounts for frequent reinfections and more severe disease in high-risk groups. RT-PCR remains the assay of choice for highly sensitive and specific diagnosis of COVID-19. There is currently no approved vaccine or antiviral therapy, and management is supportive, including oxygen therapy and respiratory support in severe cases. Ongoing promising research is directed toward antiviral agents, monoclonal antibodies, and vaccines based on mRNA or protein subunits, as well as live-attenuated and viral vector vaccines. Further studies are important to reduce HMPV attributable morbidity and mortality.