Molecular characteristics, epidemiological trends, and public health implications of human metapneumovirus (hMPV): a review.

Abstract

Human Metapneumovirus (hMPV) is an emerging respiratory pathogen associated with significant morbidity, particularly among young children, older adults, and immunocompromised individuals. Although clinically relevant, it remains underrecognized relative to influenza and respiratory syncytial virus (RSV). Recent regional outbreaks, including the January 2025 surge in northern China, highlight hMPV's capacity to cause significant above-seasonal transmission events, particularly in settings with immunity debt following prolonged non-pharmaceutical interventions. This review synthesizes current knowledge on hMPV epidemiology, genetic diversity, transmission dynamics, pathogenesis, host immune interactions, diagnostic approaches, and therapeutic and vaccine development efforts. A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, and ScienceDirect with no publication date restriction, using MeSH and free-text terms including "hMPV," "epidemiology," "immune response," "diagnosis," "treatment," and "pandemic preparedness." Relevant reference lists were hand-searched to identify additional studies. Eligible articles included molecular, clinical, observational, and epidemiological studies; case reports and commentaries were excluded unless they provided unique outbreak insights. Findings emphasize that hMPV represents a growing public health concern due to limited awareness, diagnostic overlap with other viral pathogens, and the absence of targeted therapeutics or licensed vaccines. Strengthened surveillance, improved diagnostic capacity, and accelerated research into immunopathogenesis and vaccine platforms are urgently needed. Integrating hMPV into regional outbreak preparedness frameworks rather than pandemic-level frameworks applicable to influenza or SARS-CoV-2 while fostering collaborative research and proportionate public health communication, is essential to mitigate its future impact.