HUMAN METAPNEUMOVIRUS: EPIDEMIOLOGY, PATHOGENESIS, AND CLINICAL MANIFESTATIONS

Human metapneumovirus (HMPV) is a newly identified common respiratory virus first discovered in 2001.HMPV is a leading cause of upper and lower respiratory tract infections in infants, the elderly, and immunocompromised individuals.Even though it has circulated widely for years, HMPV is often not diagnosed and does not have a licensed vaccine or specific antiviral treatment.The virus mainly spreads through respiratory droplets, direct contact, and contaminated surfaces, with peaks occurring in late winter and spring.Almost all children are exposed to HMPV by the time they are five, and they may experience reinfections throughout their lives.HMPV pathogenesis involves complex interactions between viral proteins and host immunity.The virus weakens innate immune responses, suppresses interferon signaling, and promotes a Th2-skewed inflammatory response.This leads to airway inflammation, excess mucus production, and in severe cases, bronchiolitis or pneumonia.T-cell dysfunction and immune evasion strategies result in prolonged infection and increased disease severity.Current management relies mainly on supportive care.Ribavirin, monoclonal antibodies that target the fusion (F) protein, and peptide-based fusion inhibitors have shown potential in experimental studies, but there is limited clinical evidence.Efforts to develop vaccines, including inactivated, subunit, and live-attenuated candidates, are ongoing.Fprotein-based approaches show the most promise.Until effective vaccines or targeted therapies are available, prevention strategies such as hand hygiene, respiratory etiquette, environmental disinfection, and infection control in healthcare settings is also essential.Continued research is critical to reducing the global clinical and economic burden of HMPV infections.