Epidemiology and Characteristics of Respiratory Syncytial Virus Pneumonia in Critically Ill Adults.

Background: Severe respiratory syncytial virus (RSV)-associated pneumonia in adults has rarely been addressed. We investigated the burden and clinical characteristics of severe RSV-associated pneumonia in critically ill adult patients.

Methods: We analyzed a prospective cohort of 2865 adults with severe pneumonia who were admitted to the intensive care unit in a 2700-bed tertiary care hospital from 2010 to 2019. The epidemiology, characteristics, and outcomes of 92 cases of severe RSV-associated pneumonia and 163 cases of severe influenza virus (IFV)-associated pneumonia were compared.

Results: Of 1589 cases of severe community-acquired pneumonia, the incidence of RSV-associated pneumonia was less than half that of IFV-associated pneumonia (3.4% vs 8.1%). However, among 1276 cases of severe hospital-acquired pneumonia (HAP), there were slightly more cases of RSV-associated than IFV-associated pneumonia (3.8% vs 3.5%). During the 9 epidemic seasons, RSV-A (5 seasons) and RSV-B (4 seasons) predominated alternately. Structural lung disease, diabetes mellitus, and malignancy were common underlying diseases in both groups. Immunocompromise (57.6% vs 34.4%; < .001) and hospital acquisition (47.8% vs 23.9%; < .001) were significantly more common in the RSV group. Coinfection with (3.3% vs 9.8%; = .08) and methicillin-susceptible (1.1% vs 6.8%; = .06) tended to be less frequent in the RSV group. The 90-day mortality was high in both groups (39.1% vs 40.5%; = .89).

Conclusions: RSV infection was associated with substantial morbidity and mortality in critically ill adult patients, similar to IFV. The relatively higher incidence of RSV in severe HAP suggests that the transmissibility of RSV can exceed that of IFV in a hospital setting.