[Epidemiology and clinical characteristics of human metapneumovirus]

Introduction: Human metapneumovirus (hMPV) is a respiratory pathogen that can cause severe complications, particularly in patients with certain comorbidities. Its significance has grown due to insights from the COVID–19 pandemic and the rising hMPV cases reported by the Chinese Centre for Disease Control and Prevention in late 2024. Objective: The aim of the study was to retrospectively analyze the epidemiological and clinical characteristics of hMPV cases diagnosed between 2019 and 2024 at the Central Hospital of Southern Pest National Institute of Hematology and Infectious Diseases. Method: A single-center, retrospective cohort study was conducted between December 2019 and December 2024, including all adult patients who had confirmed hMPV infection by real-time polymerase chain reaction (RT-PCR). Clinical data (demographics, comorbidities, initial clinical presentation, viral co-infection) and complications (hospitalization, oxygen requirement, pneumonitis, intensive care unit admission, mechanical ventilation, in-hospital mortality) were recorded. The primary composite endpoint, which also determined the complicated course, was based on in-hospital mortality, intensive care unit admission, or mechanical ventilation initiation. Results: A total of 80 patients were included (mean age: 58 ± 30 years; male: n = 47, 58.8%). A complicated course was observed in 10% (n = 8), which occurred significantly more frequently in older patients (66 ± 10 vs. 55±31 years, p = 0.05). Pneumonitis occurred in 45% (n = 36), hospitalization in 42.5% (n = 34), oxygen requirement in 30% (n = 24), intensive care unit admission in 8.75% (n =7), mechanical ventilation in 6.25% (n = 5), and in-hospital mortality in 6.25% (n = 5). Intensive care unit admission and in-hospital mortality were not always exclusively due to hMPV infection. Discussion: According to our findings, the clinical significance of hMPV is important in immunocompromised, elderly, and patients with chronic respiratory diseases, as the infection can lead to severe respiratory complications. Conclusion: In summary, when hMPV infection is suspected, diagnostics should be extended including hMPV, particularly in high-risk groups, as early diagnosis is crucial for preventing severe outcomes. Orv Hetil. 2025; 166(29): 1132–1138.