Laboratory Confirmation of Respiratory Syncytial Virus Infection Is Not Associated With an Increased Risk of Death in Adults With Acute Respiratory Illness.

Background: Limited data have described the testing patterns and outcomes of adults (≥18 years) with acute respiratory illness (ARI) in the emergency department setting. Methods: This prospective cohort study includes patients with ARI from a program sponsored by the Centers for Disease Control and Prevention entitled Respiratory Virus Laboratory Emergency Department Network Surveillance (RESP-LENS) from August 2021 until March 2024 (91 hospitals). Patients with ARIs were identified weekly by electronic surveillance for 1 or more of 130 Results: From 1 210 394 patients with ARI, 345 185 (28.5%) adults underwent RSV testing, which was positive in 2.4%. In adults who were RSV+, the overall mortality rate was 1.9% as compared with 2.9% in adults who were RSV-. Mortality with RSV+ status increased with age ≥65 years to 3.8% (95% CI, 3.1%-4.5%). However, in the generalized estimating equation, RSV+ status was not associated with a higher rate of hospitalization (adjusted odds, 0.79; 95% CI, .75-.84) or 30-day mortality (odds, 0.62; 95% CI, .53-.74) relative to those who were RSV-. Age ≥65 years, incremental worsening of vital signs, male sex, and heart failure were independently associated with death. Conclusions: Among adults with ARI presenting to an emergency department who were tested for RSV as part of their usual care, laboratory-confirmed RSV positivity was not associated with increased risk, including hospitalization, intensive care unit requirement, or death.