Clinical, virological, and operational aspects of a single-center Belgian experience with in-hospital infusions of casirivimab/imdevimab and sotrovimab for mild/moderate COVID-19.

Objectives: To describe the clinical and virological characteristics of COVID-19 patients treated in a hospital with casirivimab/imdevimab and sotrovimab between June 2021 and April 2022 and to report the logistics for administering these monoclonal antibodies (mAbs).

Methods: All COVID-19 adult patients treated with mAbs at CHU Charleroi (Belgium) were included. A multidisciplinary monoclonal antibodies team (MMT) was dedicated to identify eligible patients and coordinate the administration of mAbs in a temporary structure created within the hospital.

Results: A total of 69 COVID-19 patients were treated with casirivimab/imdevimab (11.6%) and sotrovimab (88.4%) within a median of 4 days of symptom onset, mainly during the Omicron B.1.1.529 period (71%); no severe adverse events occurred. Thirty-eight (55%) were outpatients, and among the 31 inpatients, 42% were nosocomial COVID-19. The median age was 65 years [IQR, 50-73], and 53.6% were male. The most common risk factors for progression to severe COVID-19 were immunosuppression (72.5%), arterial hypertension (60.9%) and age>65 years (47.8%). One fifth were SARS-CoV-2-unvaccinated patients. The median Belgian MASS score for patient prioritization was 6 [IQR, 4-8]. On Day 29, 10.5% of the outpatients were hospitalized, and 1.4% were admitted to an intensive care unit (ICU); there were no COVID-19-related deaths. General practitioners referred 19.4% of the outpatients.

Conclusions: In our experience, mAbs were prescribed in very high-risk patients with no adverse events, few progressions to severe COVID-19, and no related deaths. Our MMT has improved coordination of COVID-19 treatment and contribute to enhance communication with primary care.