Outpatient RSV Testing Rates Among US Adults with Lower Respiratory Tract Disease, 2017-2024

Respiratory syncytial virus (RSV) infection in adults causes lower respiratory tract disease (LRTD) encompassing lower respiratory tract infection (LRTI), and exacerbations of chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF), yet RSV testing rates among these patients, especially among outpatients, are not well documented. This study evaluated RSV and influenza testing practices among United States (U.S.) adults seen in outpatient settings with LRTI, COPD exacerbation, or CHF exacerbation.

We quantified RSV and influenza testing rates in a retrospective cohort of adults ≥ 18 years old seen in outpatient settings for LRTI, COPD exacerbations, or CHF exacerbations from August 2017 to March 2024 using Optum^® Electronic Health Records (EHR). The primary outcome was the occurrence of a standard-of-care RSV or influenza test.

A total of 2,208,009 LRTI outpatient encounters, 396,891 COPD and 422,648 CHF exacerbation events from the Optum^® EHR database were included in the analysis. The proportion of LRTI encounters with RSV testing increased from 0.6% in 2017 to 9.4% in 2024, but remained lower than influenza (7.1-31.7%). Viral testing among COPD and CHF exacerbation events followed similar trends. Of all eligible outpatient LRTI encounters, less than 3% (60,265/2,208,009) were tested for RSV whereas 15% (333,232/2,208,009) were tested for influenza. Exacerbation events for COPD (1.9% RSV, 6.0% influenza) were tested more frequently than CHF exacerbations (0.5% RSV, 1.1% influenza).

Despite increases over time, RSV testing remains infrequent among U.S. adult outpatients. This is particularly true among adults with COPD or CHF exacerbations, where RSV should be part of the differential diagnosis. Infrequent testing may reflect lack of specific RSV treatment options.