Introduction: Respiratory syncytial virus (RSV) and influenza virus are important respiratory viruses. Although RSV vaccines have been developed and recommended for patients aged ≥ 60, there is limited data on the clinical impact among the non-elderly population. It is also important to know the patient subgroups that are at risk of complications from RSV infections.
Methods: We conducted a territory-wide retrospective study on adults hospitalized for RSV or influenza virus infection between 1/1/2016 and 6/30/2023 in Hong Kong. The in-patient mortality, severe respiratory failure (SRF), secondary bacterial pneumonia, and acute kidney injury (AKI) were compared. Subgroup analyses were performed in different age groups. The risk factors for mortality and serious respiratory outcomes were assessed.
Results: A total of 41,206 and 3565 patients were hospitalized for influenza and RSV infections. Patients with RSV infection showed a significantly higher risk of in-patient mortality, SRF, secondary bacterial pneumonia, and AKI compared with those with influenza (p < 0.001, for all), and the results were consistent for patients aged ≥ 60, < 60, and 50-59. End-stage kidney disease requiring real replacement therapy was an independent risk factor for in-patient mortality and serious respiratory outcomes in RSV infection across different age groups (p < 0.001, for all).
Conclusions: Adults hospitalized for RSV infection were associated with a significantly increased risk of in-patient mortality and adverse respiratory and kidney outcomes than those with influenza. The findings are consistent across various age groups, and the results call for an update on RSV vaccination recommendations in adults, especially for vulnerable subgroups.
Keywords: acute kidney injury; chronic kidney disease; dialysis; mortality; respiratory syncytial virus.
© 2025 The Author(s). Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.