Volume 177, April 2025, 105775Author links open overlay panel, , , , , , , , , , , , , , Highlights•

Largest study on RSV vs. flu mortality in EDs pre/post-COVID.

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RSV had more hospitalizations, but similar mortality.

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One-year event rates were similar for both infections.

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Supports vigilance, resource allocation & RSV vaccination.

AbstractObjective

In recent years, there has been increased awareness of the impact of respiratory syncytial virus (RSV) on adult health, especially in elderly patients. Unlike influenza infection, its presentation and patient outcomes are not well studied. The aim of this study was to compare clinical outcomes in emergency department patients infected by RSV vs influenza.

Methods

This was a multicenter retrospective study in seven emergency departments (ED) in France. Patients with a laboratory-confirmed RSV or influenza infection in the ED were included between January 2017 and December 2022. The primary endpoint was in-hospital mortality truncated at day 28. Secondary endpoints included one year occurrence of thrombo-embolic event, acute coronary syndrome, and stroke.

Results

3397 patient charts were screened, and 3224 were analyzed. Of these, 551 (17 %) patients had RSV-positive PCR, and 2673 (83 %) had influenza-positive PCR. Patients with RSV were older (median age 73 vs. 68; difference, −5.00 % points [CI, −4.0 to −6.0 % points])), and had more comorbidities (15.0 % vs 22.0 % difference, −6.92 % points [CI, −10.6 to −3.21 % points])), compared to those with influenza. There was no significant difference in in-hospital mortality rate at day 28: 3.82 % for influenza vs. 4.72 % for RSV (adjusted OR 0.93, 95 %CI [0.59–1.46] p = 0.73). There was no significant difference in the occurrence of the secondary endpoints.

Conclusions

In this large study of ED patients, although RSV patients were more fragile, no significant differences were found in in-hospital mortality or the occurrence of cardiovascular or thromboembolic events between RSV and influenza infections.

Keywords

RSV

Influenza

Respiratory viruses

Data availabilityData collected for the study, including individual participant data and the data dictionary, will be made available on reasonable request. Data will be provided as de-identified participant data in accordance with French law and will be available after publication of the manuscript. Data requests should be addressed to Donia Bouzid ([email protected]) or Yonathan Freund ([email protected]), who will send the data after approval, after requestors provide a signed data access agreement.

© 2025 The Authors. Published by Elsevier B.V.