Disease Burden of RSV Infection in Adult Patients in Comparison to Influenza Virus Infection.

Respiratory Syncytial Virus (RSV) is well known for its impact on children, but its burden in adults remains underexplored, partly due to limited PCR testing before the COVID-19 pandemic. In this study, the medical burden of RSV infections in adults was retrospectively investigated using 6-year longitudinal data from a university hospital in North Rhine-Westphalia, Germany. Outcomes of 380 PCR-confirmed RSV cases were compared with 1088 influenza A/B cases from 2018 to 2023, stratified by age groups ( < 60 and ≥ 60 years). Among RSV cases, 59.7% required hospitalization, of which 22.9% needed oxygen supply. In the whole group hospitalization rates were comparable between RSV and influenza cases, but oxygen supply was more frequent in influenza infections. However, in patients aged ≥ 60 years, no significant differences were observed in hospitalization, oxygen supply, or fatal outcomes between RSV and influenza, indicating a comparable disease burden for both viruses in this group. These findings highlight the significant clinical impact of RSV in adults, particularly those aged ≥ 60 years, paralleling that of influenza. Given influenza's established pathogenic reputation, this underscores the importance of targeted vaccination strategies against RSV, especially for high-risk age groups.