Retrospective analysis of human metapneumovirus in hospitalized and outpatient children: Insights from a four-year experience in Türkiye

Objective: Human metapneumovirus (hMPV), particularly affecting children under five, is a significant viral agent associated with a wide range of respiratory illnesses, from mild upper respiratory infections to severe lower respiratory tract involvement. This study aimed to evaluate the clinical characteristics, severity indicators, and seasonal distribution of hMPV infections over a four-year period in one of Türkiye’s largest pediatric hospitals, and to assess the potential epidemic risk in the national context. Material and Methods: This retrospective study included 345 pediatric patients diagnosed with hMPV between January 2021 and December 2024. Demographic data, clinical findings, hospitalization status, respiratory support requirements, imaging results, and outcomes were analyzed. Results: The median age was four years; 44.6% of patients were hospitalized, and 9.2% required intensive care. Common symptoms included cough (84.1%), fever (65.8%), and rhinorrhea (59.7%). Hypoxia, tachypnea, and pulmonary infiltrates were significantly associated with hospitalization (p<0.001). Four patients died, three without known comorbidities. The highest case count occurred in 2022, followed by a marked decline in 2023–2024, consistent with global trends. Conclusion: Although generally considered mild, hMPV infection can result in severe disease and mortality, even in healthy children. These findings highlight the importance of early risk identification and integration of hMPV into respiratory infection surveillance and public health strategies. No significant outbreak was observed in Türkiye during the study period.