ABSTRACT
Background: Kidney transplant recipients (KTR) are at higher risk for breakthrough COVID-19 infections and progression to severe disease. Herein, we compare the outcomes of KTR infected with the Delta and Omicron variants. Method(s): We performed a retrospective, single-centre study of all SARS-CoV-2-infected KTR confirmed by PCR from 17/09/21 to 30/04/22. At diagnosis, anti-metabolite doses were halved with further reductions of immunosuppression with increasing disease severity. Treatment for KTR not requiring supplemental oxygen (SuppO2) on admission was guided by SARS-CoV-2 spike antibody (SpAb), Roche Cobas SARSCoV-2-S assay. Sotrovimab 500mg IV was given if SpAb<100 U/mL. With community emergence of Omicron subvariant BA.2, sotrovimab was replaced by tixagevimab/ cilgavimab (EVUSHELDTM) 600mg IM in KTR with SpAb<250 U/mL or remdesivir if SpAb>250 U/mL. KTR with SuppO2 were treated with dexamethasone +/-remdesivir and immunomodulator therapy (baricitinib or tocilizumab). Characteristics and outcomes between KTR with Delta and Omicron were compared. Result(s): Clinical characteristics and outcomes are summarized in Table 1. Baseline demographics were similar between groups. Vaccination rates increased over time in concert with government vaccine programs and communications by our team. KTR with Omicron had higher vaccination rates, higher likelihood of SpAb>250 U/mL, and were less likely to have AKI, SuppO2, ICU stay, and mortality (p<0.05 for all). Of 16 KTR with Omicron with SuppO2, 5 were unvaccinated and only 1/16 had SpAb>250 u/mL. Conclusion(s): Severe disease was less frequent in KTR with Omicron likely due to improved vaccination rates, higher SpAb, and virus characteristics. However, KTR remain at risk for severe disease especially if unvaccinated or if SpAb is low.