Effectiveness of Sotrovimab in Preventing COVID-19-related Hospitalizations or Deaths Among U.S. Veterans

Background: Data on effectiveness of sotrovimab preventing COVID-19-related hospitalization or mortality, particularly after the emergence of the Omicron variant, are limited. Method: Determine the real-world clinical effectiveness of sotrovimab for prevention of 30-day COVID-19 related hospitalization or mortality using a retrospective cohort within the U.S. Department of Veterans Affairs (VA) healthcare system. Veterans aged [≥]18 years, diagnosed with COVID-19 between December 1, 2021, and April 4, 2022, were included. Sotrovimab recipients (n=2,816) were exactly matched to untreated controls (n=11,250) on date of diagnosis, vaccination status, and region. The primary outcome was COVID-19-related hospitalization or all-cause mortality within 30 days from diagnosis. Cox proportional hazards modeling estimated the hazard ratios (HR) and 95% Confidence Interval (CI) for the association between receipt of sotrovimab and outcomes. Results: During BA.1 dominance, compared to matched controls, sotrovimab-treated patients had a 70% lower risk hospitalization within 30 days or mortality (HR 0.30; 95%CI, 0.23-0.40), a 66% lower risk of 30-day hospitalization (HR 0.34; 95%CI, 0.25-0.46), and a 77% lower risk of 30-day all-cause mortality (HR 0.23; 95%CI, 0.14-0.38). During BA.2 dominance sotrovimab-treated patients had a 71% (HR .29; 95%CI, 0.08-0.98) lower risk of 30-day COVID-19-related- hospitalization, emergency, or urgent care. Limitations include confounding by indication. Conclusions: Using national real-world data from high risk and predominantly vaccinated Veterans, administration of sotrovimab, compared with no treatment, was associated with reduced risk of 30-day COVID-19-related hospitalization or all-cause mortality during the Omicron BA.1 period and reduced risk of progression to severe COVID-19 during the BA.2 dominant period.