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

Loubet, Paul; Mathieu, Pauline; Lenzi, Nezha; Galtier, Florence; Lainé, Fabrice; Lesieur, Zineb; Vanhems, Philippe; Duval, Xavier; Postil, Deborah; Amour, Sélilah; Rogez, Sylvie; Lagathu, Gisèle; L'Honneur, Anne-Sophie; Foulongne, Vincent; Houhou, Nadhira; Lina, Bruno; Carrat, Fabrice; Launay, Odile

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 <7 days). Data were collected from five French teaching hospitals over six consecutive winters (2012-2018). Respiratory viruses were identified by multiplex RT-PCR on nasopharyngeal specimens. hMPV+ patients were compared to hMPV– patients, influenza+ and respiratory syncytial virus (RSV)+ patients using multivariate logistic regressions. Primary outcome was the prevalence of hMPV in patients hospitalized for ILI. 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.