Characteristics of human metapneumovirus infection in adults hospitalized for community-acquired influenza-like illness in France, 2012-2018: a retrospective observational study.

Abstract Objectives To describe the prevalence, clinical features and complications of human metapneumovirus (hMPV) infections in a population of adults hospitalized with influenza-like illness (ILI). Methods This was a retrospective, observational, multicenter cohort study using prospectively collected data from adult patients hospitalized during influenza virus circulation, for at least 24h, for community-acquired ILI (with symptom onset Results Among the 3148 patients included (1449 (46%) women, 1988 (63%) aged 65 and over; 2508 (80%) with chronic disease), at least one respiratory virus was detected in 1604 (51%, 95%CI [49-53]), including 100 cases of hMPV (100/3148, 3% 95%CI [3-4]), of which 10 (10%) were viral co-infection. In the hMPV+ patients, mean length of stay was 7 days, 62% (56/90) developed a complication, 21% (14/68) were admitted to intensive care unit and 4% (4/90) died during hospitalization. In comparison with influenza+ patients, hMPV+ patients were more frequently > 65 years old (aOR=3.3, 95%CI[1.9-6.3]) and presented more acute heart failure during hospitalization (aOR=1.8, 95%CI[1.0-2.9]). Compared to RSV+ patients, hMPV+ patients had less cancer (aOR=0.4, 95%CI[0.2-0.9]) and were less likely to smoke (aOR=0.5, 95%CI[0.2-0.9]) but had similar outcomes especially high rate of respiratory and cardiovascular complications. Conclusions Adult hMPV infections mainly affect the elderly and patients with chronic conditions and are responsible for frequent cardiac and pulmonary complications similar to those of RSV infections. At-risk populations would benefit from the development of antivirals and vaccines targeting hMPV.