Human Metapneumovirus (HMPV): Unveiling the Silent Respiratory Threat

Human Metapneumovirus (HMPV), a highly significant but underappreciated pathogen, is responsible for a substantial number of respiratory infections worldwide.

- Dr. Alka Rajput Shri Dhanwantry Ayurvedic College and Hospital, Chandigarh, India

Since its discovery in 2001, HMPV, a member of the Pneumoviridae family, has gained recognition for its potential to cause severe respiratory illness across different age groups, particularly in vulnerable populations such as young children, the elderly and immunocompromised individuals. Despite its clinical significance, HMPV has not received the same level of attention as other common respiratory pathogens, such as Respiratory Syncytial Virus (RSV) or influenza, leaving a significant knowledge gap and underreporting of its impact.

Virology and Epidemiology

HMPV is an envelope, negative-sense RNA virus that shares genetic similarities with RSV, though they belong to different genera within the Pneumoviridae family. The virus is categorized into two major genotypes: A and B, which are further subdivided into multiple subgroups based on genetic and antigenic variations. These genotypes are associated with differing clinical manifestations, epidemiological patterns, and transmission dynamics.

The viral genome encodes essential structural proteins, including the fusion (F) protein and glycoprotein (G), both of which play key roles in viral infectivity and immune evasion. The F protein mediates viral entry by facilitating fusion with the host cell membrane, while the G protein is involved in viral attachment to host cell receptors and modulating the host immune response. The understanding of these molecular interactions is crucial in the design of antiviral therapies and vaccines. Recent studies have reported the identification of mutations in the F and G proteins that could affect viral virulence, transmission, and the host's immune response. HMPV circulates seasonally, with peak incidences often observed during late winter and early spring.

Clinical Manifestations