Sundararajan, Ramaswamy

Abstract Background Data describing the incidence and clinical outcomes of respiratory syncytial virus (RSV) infection among patients with inflammatory bowel disease (IBD) are limited. Methods We conducted a nationwide retrospective cohort study using the Veterans Health Administration (VHA) database. Adults with IBD were identified using a previously validated algorithm and matched 1:2 to non-IBD controls using propensity score matching. Laboratory-confirmed RSV infections that occurred between January 1, 2021, and December 31, 2024, were identified using standardized laboratory codes and confirmed by manual chart adjudication. Primary outcomes included RSV incidence and hospitalizations. Secondary outcomes included intensive care unit (ICU) admission and patient outcomes stratified by IBD medication class. Results After propensity score matching, 52 740 IBD patients and 104 997 non-IBD controls were included. Infection with RSV occurred in 219 patients with IBD and 426 non-IBD patients. Incidence rates of RSV were similar between cohorts across all years in our study period. Hospitalization related to RSV occurred in 18.26% of IBD-RSV patients compared with 13.15% of non-IBD patients (P = .08). ICU admission was rare in both groups (<1%). Among patients with IBD, RSV-related hospitalization did not differ significantly by medication class, when comparing biologic therapy (8.93%) with 5-aminosalicylic acid monotherapy (17.58%) (P = .15). Conclusions In this nationwide cohort, patients with IBD, with predominantly lower exposure to advanced therapies, did not have higher rates of RSV infection or worse clinical outcomes compared with matched non-IBD controls. RSV outcomes were similar across IBD medication classes. These findings support current vaccination recommendations and provide reassurance regarding RSV risk among patients with IBD.