Assessment of unvaccinated and vaccinated patients with coronavirus disease 2019 (COVID-19) treated with monoclonal antibodies during the delta wave (July 1–August 20, 2021): a retrospective observational monocentric study

Abstract

Background Monoclonal antibodies (mAb) prevent COVID-19 progression when administered early. We compared mAb treatment outcomes among vaccinated and unvaccinated patients during Delta wave and assessed the feasibility of implementing stricter eligibility criteria in the event of mAb scarcity. 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). Primary 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 (p < 0.0001). The median number of EUA criteria met was 1 for unvaccinated and 2 for vaccinated patients (p < 0.0001). Overall, 6% (15/250) of patients were admitted within 30 days post-treatment. Eleven unvaccinated patients (7%) were admitted within 30-days compared to 4 (5%) vaccinated patients (p = 0.48). Conclusions All-cause 30-day admission was not statistically different between vaccinated and unvaccinated patients. When federal allocation of therapies is limited, programs must prioritize patients at highest risk of hospitalization and death regardless of vaccination status.

Retrospective Analysis of Vaccinated and Unvaccinated COVID-19 Patients Treated with Monoclonal Antibodies (mAb) and Their Emergent Needs (RAVEN)

“…In another smaller study of 250 patients, Guo et al failed to find a statistically significant difference in the frequency of hospitalization following mAb infusion between vaccinated and unvaccinated patients (5% vs. 7%, respectively). This study included a younger patient population with fewer comorbidities and had an uneven distribution between vaccinated ( n = 162) and unvaccinated ( n = 8) patients [ 21 ]. Keshishian et al performed a single-center study that included 743 patients, with the majority (585) being unvaccinated.…”

“…While vaccination and mAb are independently associated with reduced hospitalization and all-cause mortality in COVID-19 positive patients, and mAb therapy further decreases the risk of disease progression in vaccinated patients [ 18 , 19 , 20 ], data comparing clinical outcomes in vaccinated and unvaccinated patients treated with mAb is unclear. Studies examining mAb treatment outcomes regarding vaccination status had conflicting results [ 21 , 22 ]. There remains a need to ascertain a difference in response to the mAb therapy between vaccinated and unvaccinated patients.…”