A Single-Center Retrospective Study on Early Treatment for COVID-19 in Solid Organ Transplant Recipients During the Omicron Era: Outcomes and SARS-CoV-2 Viral Kinetics

Solid organ transplant recipients (SOTRs) are at high risk of severe coronavirus disease 2019 (COVID-19), therefore early treatment of mild infections is crucial to prevent increased morbidity and mortality. The effectiveness of early treatment in SOTRs has yet to be fully characterized due to the emergence of new SARS-CoV-2 variants and to COVID-19 vaccination implementation. The aim of this single-center retrospective study is to evaluate the outcomes, safety and impact on SARS-CoV-2 viral load kinetics of COVID-19 early treatment in SOTRs. The study includes 80 SOTRs with a laboratory-confirmed diagnosis of symptomatic SARS-CoV-2 infection enrolled between January and October 2022 and treated with either monoclonal antibodies or antivirals. All patients received COVID-19 vaccination and 68.8% of them showed detectable levels of anti-spike (S) antibodies. The occurrence of clinical events (hospitalization, intensive care unit admission, or death) was assessed within 30 days after treatment initiation. The quantification of SARS-CoV-2 viral load were performed at baseline and at day-7. The rate of hospitalization was 2.5% [0.3-9%] and no deaths occurred. All patients completed treatment with no serious adverse events. Median viral load decrease was 0.48 [0.26-0.69] log₂ cycle threshold (ct) values, with no significant differences between SOTRs treated with monoclonal antibodies and those treated with antivirals. Viral load decrease was significantly associated with positive anti-s serology at baseline (β = 0.196, <i>p</i> = 0.01), number of days between symptom onset and treatment (β = 0.05, <i>p</i> = 0.03) and the number of comorbidities (β = -0.05, <i>p</i> = 0.03). We provide evidence of real-world effectiveness of early therapy in SOTRs infected with SARS-CoV-2 and demonstrate the relevant role of humoral response to vaccination in enhancing early viral load decay during treatment.