Human metapneumovirus infection is associated with a substantial morbidity and mortality burden in adult inpatients

BackgroundHuman metapneumovirus (hMPV) is one of the leading respiratory viruses. This prospective observational study aimed to describe the clinical features and the outcomes of hMPV-associated lower respiratory tract infections in adult inpatients.MethodsConsecutive adult patients admitted to one of the 31 participating centers with an acute lower respiratory tract infection and a respiratory multiplex PCR positive for hMPV were included. A primary composite end point of complicated course (hospital death and/or the need for invasive mechanical ventilation) was used.ResultsBetween March 2018 and May 2019, 208 patients were included. The median age was 74 62-84 years. Ninety-seven (47%) patients were men, 187 (90%) had at least one coexisting illness, and 67 (31%) were immunocompromised. Median time between first symptoms and hospital admission was 3 2-7 days. The two most frequent symptoms were dyspnea (86%) and cough (85%). The three most frequent clinical diagnoses were pneumonia (42%), acute bronchitis (20%) and acute exacerbation of chronic obstructive pulmonary disease (16%). Among the 52 (25%) patients who had a lung CT-scan, the most frequent abnormality was ground glass opacity (41%). While over four-fifths of patients (81%) received empirical antibiotic therapy, a bacterial coinfection was diagnosed in 61 (29%) patients. Mixed flora (16%) and enterobacteria (5%) were the predominant documentations. The composite criterion of complicated course was assessable in 202 (97%) patients, and present in 37 (18%) of them. In the subpopulation of pneumonia patients (42%), we observed a more complicated course in those with a bacterial coinfection (8/24, 33%) as compared to those without (5/60, 8%) (p=0.02). Sixty (29%) patients were admitted to the intensive care unit. Among them, 23 (38%) patients required invasive mechanical ventilation. In multivariable analysis, tachycardia and alteration of consciousness were identified as risk factors for complicated course.ConclusionhMPV-associated lower respiratory tract infections in adult inpatients mostly involved elderly people with pre-existing conditions. Bacterial coinfection was present in nearly 30 % of the patients. The need for mechanical ventilation and/or the hospital death were observed in almost 20 % of the patients.