Testing for respiratory syncytial virus (RSV) in Greek adults hospitalized with community-acquired pneumonia (CAP)

<bold>Background:</bold> RSV, with the increasing use of molecular tests, has been recognized as a significant cause of adult respiratory infections. <bold>Aims and objectives:</bold> EGNATIA study aimed to assess RSV prevalence in adult hospitalized CAP. <bold>Methods:</bold> EGNATIA is a 6-year, prospective study of adults aged ≥19 years hospitalized with radiographically confirmed CAP in the Ioannina and Kavala regions, Greece. The primary objective is to assess pneumococcal serotype distribution. Among secondary objectives, we estimated RSV prevalence for the last study year (2022-2023). RSV was detected by real-time polymerase chain reaction (RT-PCR) from nasopharyngeal swabs (NPS) and, if available, saliva/oropharyngeal swabs (OPS). <bold>Results:</bold> 215 hospitalized CAP patients had at least one sample tested for RSV from November 2022 to July 2023. RSV was detected in 12 patients (5.6%) overall. Among the 176 patients with NPS and saliva/OPS collected, the addition of saliva/OPS increased the RSV detection by 13%, from 4.5% (8/176) to 5.1% (9/176). All RSV cases were detected over Dec2022-Feb2023, corresponding to a 12.8% positivity rate over this period. Mean age of the RSV patients was 76.5 years. The majority (91.7%) were female. Most frequent comorbidities were diabetes mellitus (33.3%), coronary artery disease (16.7%), chronic obstructive pulmonary disease (16.7%) and asthma (16.7%). Among the RSV patients, 75% fell into Pneumonia Severity Index (PSI) risk classes III/IV. In-hospital mortality was 8.3%. <bold>Conclusions:</bold> RSV was identified as a common pathogen in adult hospitalized CAP in Greece over the 2022-2023 respiratory season. As in other adult studies, adding saliva/OPS to NPS increased RSV detection.