Epidemiology, Clinical Features, and Molecular Characteristics of Human Metapneumovirus (HMPV): A Meta-Analysis

Abstract

Human Metapneumovirus (HMPV) was first described in 2001 in the Netherlands and has become an important pathogen in the Pneumoviridae family, causing significant paediatric and adult respiratory infections worldwide. This review synthesizes the clinical manifestations, genetic diversity, epidemiology, and pathogenesis of the virus based on findings of more than two decades' worth of research. HMPV is not only highly infectious, but it carries a burden in the form of its tendency to result in severe respiratory disease in children, the elderly, and the immunocompromised, often causing lengthy hospitalizations and remarkable expenditures in healthcare. Unlike RSV, HMPV has defined age-related infection patterns and a unique genetic architecture, with the G glycoprotein that is highly variable making subclassification and antigenicity dependent upon this variation. Current subtypes (such as A2b1) demonstrate the scourge of the virus’s adaptability and thus raise obstacles to its vaccine development. HMPV pathogenetically infects ciliated epithelial cells, disrupting mucociliary function, producing robust inflammatory responses, and worsening disease severity. Advanced molecular diagnostics and therapeutic approaches have nonetheless been accompanied by little progress in developing specific antiviral treatments or vaccines, a need underscored by the urgency of such focused research and public health interventions. Finally, these findings are integrated to achieve a complete picture of HMPV and to progress future research and clinical approaches regarding this important respiratory pathogen.