Characteristics and outcomes of intensive care unit patients with respiratory syncytial virus compared to those with influenza infection: a multicentre matched cohort study.

The characteristics and outcomes of adult patients with respiratory syncytial virus (RSV) infection who require intensive care unit (ICU) admission are poorly defined. Although several studies in adults with RSV infection have been published in recent years, they did not focus specifically on critically ill patients. What are the characteristics and outcomes of adult ICU patients with RSV infection, and how do they compare to those of ICU patients with influenza infection? This retrospective, multicentre study in France and Belgium (17 sites) compared the characteristics and outcomes of adult ICU patients with RSV infection versus influenza infection between November 2011 and April 2018. Each patient with RSV infection was matched by institution and date of diagnosis with a patient with influenza infection. In-hospital mortality was compared between the two groups, with adjustment for prognostic factors in a multivariable model (sex, age, main underlying conditions, and concurrent bloodstream infection). Data from 618 patients (309 with RSV infection and 309 with influenza infection) were analysed. Patients with RSV infection were significantly more likely to have an underlying chronic respiratory condition (60.2% versus 40.1%, p<0.001) and to be immunocompromised (35% versus 26.2%, p=0.02) than patients with influenza infection. There were several differences in clinical signs and biological data at diagnosis between the groups. In-hospital mortality was not significantly different in the two groups (23.9% in the RSV group versus 25.6% in the influenza group, p=0.63), even after adjustment for prognostic factors in a multivariable model. Adult ICU patients with RSV infection differ from adult ICU patients with influenza in terms of comorbidities and characteristics at diagnosis. RSV infection was associated with high in-hospital mortality, approaching 25%. In multivariable analysis, RSV infection was associated with a similar odds of in-hospital death compared to i