SARS-CoV-2 Pre-Exposure Prophylaxis with Sotrovimab and Tixagevimab/Cilgavimab in Immunocompromised Patients—A Single-Center Experience

Immunocompromised patients experience reduced vaccine effectiveness and are at higher risk for coronavirus disease 19 (COVID-19) death. Pre-exposure prophylaxis (PrEP) aims to protect these patients. So far, only tixagevimab/cilgavimab is authorized for use as PrEP. This paper aims to provide real-world data on the use of tixagevimab/cilgavimab and sotrovimab as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PrEP in immunocompromised patients, comparing the evolution of antibody levels and reporting the incidence of breakthrough infections. A retrospective, single-center analysis was conducted including 132 immunocompromised patients with inadequate vaccine response, who received COVID-PrEP at our clinic between January and June 2022. Initially, 95 patients received sotrovimab while 37 patients received tixagevimab/cilgavimab. Antibody levels after first PrEP with sotrovimab remain high for several months after infusion (median 10,058 and 7235 BAU/mL after 1 and 3 months, respectively), with higher titers than after tixagevimab/cilgavimab injection even 3 months later (7235 vs. 1647 BAU/mL, p = 0.0007). Overall, breakthrough infections were rare (13/132, 10%) when compared to overall infection rates during this period (over 30% of the Austrian population), with mild disease course and rapid viral clearance (median 10 days). Sotrovimab may be an additional option for SARS-CoV-2 PrEP.