Morbidity and mortality of respiratory syncytial virus infection in hospitalized adults: Comparison with seasonal influenza

Introduction: Respiratory syncytial virus (RSV) is considered a major pathogen that causes acute influenza-like illness. The objective of this study was to compare the clinical outcomes of patients with laboratory-confirmed RSV and patients with influenza infection. Methods: Adults hospitalized in Beilinson Hospital (October 2017–April 2018) with laboratory-confirmed RSV or influenza were included. The primary outcome was the composite of RSV/influenza complications: 30-day mortality, pneumonia, mechanical ventilation, vasopressor support, intensive care unit admission, and myocarditis/encephalitis. Secondary outcomes were individual components of the primary outcome, 90-day mortality, 90-day readmission, and length of hospital stay. Results: A total of 639 patients with RSV (n = 113) and influenza (n = 526) were included. The composite primary outcome was 21.4% (136/633), and was higher in RSV patients (30% (34/113) vs 19% (102/526), p = 0.002). Pneumonia was more common in RSV patients (21.2% (24/113) vs 9.1% (48/526), p = 0.001). On multivariable analysis, hypoalbuminemia (odds ratio (OR) 3.3, 95% confidence interval (CI) 2.1–5.3, p < 0.001), reduced room-air saturation (OR 1.1, 95% CI 1.02–1.1, p = 0.001), and infection with RSV (OR 1.67, 95% CI 1.01–2.76, p = 0.046) were predictors of complications. Conclusions: RSV infection in hospitalized adults resulted in serious respiratory illness with complications that are comparable to those caused by influenza.