Clinical Phenotypes and Molecular Characteristics of Respiratory Syncytial Virus in adults: a monocentric prospective study between 2019 and 2022.

Respiratory syncytial virus (RSV) infection is a major cause of pneumonia in adults. Little is known on the viral genetic diversity and the associated clinical phenotypes in this population. In this single-center prospective cohort study, RSV-infected patients between January 2019 and December 2022 were included. Of 100 patients, including 41 with severe infection, 72 were infected with RSV-B. RSV genome sequencing showed no clustering according to severity. Patients infected with RSV-B with risk factors for severe pneumonia had a significantly higher F diversity score. No amino-acid substitutions conferring resistance to nirsevimab was detected.