507. Impact of COVID-19 variant prevalence on hospitalization rate among individuals receiving monoclonal antibodies within a community health-system

Abstract Background During the COVID-19 pandemic, multiple targeted monoclonal antibodies were used in high risk patients with early COVID-19 to prevent complications. Serving as the primary referral site for a large geographic region in central North Carolina, our rural community health-system administered monoclonal agents to COVID-19 positive patients from December 2020 to November 2022. During this time period three predominate variants emerged (alpha, delta and omicron). Monoclonal Antibody Infusions at FirstHealth of the Carolinas, December 2020-November 2022 Methods A retrospective study was conducted at FirstHealth of the Carolinas Moore Regional Hospital examining patients from December 1st, 2020 to November 30th, 2022. All COVID-19 positive patients receiving one of the COVID-19 monoclonal therapies granted emergency use authorization during the study period were included. Patients were sub-divided into three distinct time periods representing different variants based on the prevalent pathogen in our region: December 2020 – June 2021 (alpha); July 2021- December 2021 (delta); January 2022-November 2022 (omicron). Hospitalization rates post monoclonal treatment were compared between time periods. Results 1820 monoclonal antibody infusions for COVID-19 were administered within the FirstHealth of the Carolinas system in the period studied. Number of infusions were highest during delta with over 60% of the infusions occurring during this period. Hospitalization rates in this group were 3.5% (alpha), 3.5% (delta), and 2.0% (omicron). Vaccination status among individuals getting monoclonal antibody infusions changed over time based on changing infusion criteria and variant prevalence. Conclusion In a real world, rural, community health care setting in the Southeast United States - hospitalization rates for high-risk individuals receiving monoclonal antibody infusions for COVID-19 were similar to reported rates and varied by variant prevalence. This is may be due to alterations in variant severity as well as vaccination status of the population. Disclosures All Authors: No reported disclosures