A Real-World Assessment of Unvaccinated And Vaccinated Patients With Coronavirus Disease 2019 (COVID-19) Treated With Monoclonal Antibodies During The Delta Wave

Background: Monoclonal antibodies (mAb) prevent COVID-19 progression during early disease presentation. We aimed to compare the mAb treatment outcomes among vaccinated and unvaccinated patients during Delta wave and assess the feasibility of implementing stricter eligibility criteria given mAb scarcity in New York City.Methods: We conducted a retrospective observational study of casirivimab/imdevimab recipients with mild-to-moderate COVID-19 infection in an emergency department or outpatient infusion center (July 1 – August 20, 2021). The outcome was all-cause hospital admission within 30 days post-treatment between vaccinated vs. unvaccinated patients during Delta surge in the Bronx, NY. Results: A total of 250 patients received casirivimab/imdevimab (162 unvaccinated vs. 88 vaccinated). The median age was 39 years for unvaccinated patients, and 52 years for vaccinated patients (pConclusions: All-cause 30-day admission was not statistically different between vaccinated and unvaccinated patients. With limited federal allocation of therapies, programs must prioritize patients at highest risk of hospitalization and death regardless of vaccination status.