INTRODUCTION: The burden of Respiratory Syncytial Virus (RSV) associated adult emergency department visits in comparison to other respiratory viruses like Influenza and SARS-CoV-2 remains less studied.

METHODS: We performed a prospective observational study to describe prevalence, severity and risk factors of RSV infection, proven by polymerase chain reaction from nasopharyngeal or pharyngeal swabs, in consecutive adult patients presenting to the emergency ward of the University Hospital Dresden with a working diagnosis of acute respiratory tract infection during the winter season between October 1st 2023 and April 15th 2024.

RESULTS: 1764 adults (56.3% male) between 18 and 101 years old (median age 69 years) were included in the analysis. 477 patients (27.1%) tested positive for viral infection; 284 (16.2%) with SARS-CoV-2 (median age 79 years), 147 (8.4%) with Influenza A or B (median age 56 years) and 38 (2.2%) with RSV A or B (median age 79 years). In 8 patients (0.5%) a co-infection with two viruses was detected. In the RSV cohort any oxygen support was significantly higher (63.2%) compared to the Influenza (34.0%, p < 0.001) and SARS-CoV-2 (41.5%, p = 0.012) cohorts. In-hospital mortality was considerable especially for RSV with 7.9% compared to Influenza (2.7%, p = 0.138) and SARS-CoV-2 (5.6%, p = 0.580).

CONCLUSION: RSV was less frequent in adults presenting to the emergency department during the 2023/24 season compared to SARS-CoV-2 and Influenza, but patients needed a higher level of respiratory support. Also, in-hospital mortality was considerable, making RSV-infections a relevant pathogen in adult patients presenting with respiratory tract infection to an emergency department.