<scp>COVID</scp> ‐19 Infection Increases the Risk of Subsequent Diagnosis of Chronic Rhinosinusitis

ABSTRACT Objectives To analyze the impact of COVID‐19 infection on the diagnosis of chronic rhinosinusitis (CRS). Methods TriNetX, a large international database of anonymized health records, was queried for adults with either positive or negative SARS‐CoV‐2 polymerase chain reaction (PCR) tests between March 1, 2020 and December 31, 2024. Patients with cancer or immunodeficiency before the COVID‐19 diagnosis were excluded. Propensity score matching was used to create comparable exposure and control groups. Relative risk ratios and Cox proportional hazards regression analysis of CRS diagnosis were calculated 3 months after PCR testing. Sub‐analyses were completed to investigate the effects of prior COVID‐19 infection on subsequent CRS development stratified by prior vaccination status and by variant‐dominant time periods (pre‐Delta, Delta, and Omicron). Results Propensity score‐matched COVID‐19+ and COVID‐19− cohorts each consisted of 2,135,446 patients. Rate of diagnosis of CRS increased following a positive COVID‐19 PCR test (RR = 2.13, 95% CI [2.10–2.16]) and varied across variant‐dominant periods, with risk ratios of 1.44 (95% CI [1.41–1.47]) during pre‐Delta, 1.20 (95% CI [1.15–1.25]) during Delta, and 2.10 (95% CI [2.07–2.13]) during Omicron. Prior COVID‐19 vaccination did not modify the risk of CRS among patients with a positive COVID‐19 PCR (RR = 0.98, 95% CI [0.92–1.05]). Conclusions COVID‐19 infection was found to increase the risk of subsequent diagnosis of CRS. Further studies are needed to better understand the relationship between COVID‐19 and the development of sinonasal inflammatory pathology. Level of Evidence 3.