Clinical Factors Associated with Documented Radiographic Pneumonia in Adults with Human Metapneumovirus Infection: A Hospital-Wide Cohort Study in Japan

Background/Objectives: Human metapneumovirus (hMPV) is increasingly recognized as an important cause of adult respiratory infection, but data on pneumonia remain limited. We evaluated clinical characteristics, temporal detection patterns, and clinical factors associated with radiographic pneumonia among adults with laboratory-confirmed hMPV infection.

Methods

We conducted a single-center retrospective observational study at Kyorin University Hospital, Tokyo, Japan, from December 2020 to February 2026. Adults aged ≥18 years with hMPV detected by multiplex polymerase chain reaction were included. The primary outcome, documented radiographic pneumonia, was defined by newly identified pneumonia-compatible parenchymal abnormalities on chest radiography and/or chest computed tomography (CT). Logistic regression was used to identify clinical factors associated with this outcome.