LAUSR

The neutralizing monoclonal antibody combination of tixagevimab/cilgavimab has been shown to reduce the risk of SARS‐CoV‐2 infection in unvaccinated individuals during the Alpha (B.1.1.7) and Delta (B.1.617.2) waves. However, data on the efficacy and safety of tixagevimab/cilgavimab in vaccinated solid organ transplant recipients during the Omicron wave is limited. To address this, we conducted a retrospective cohort study comparing 222 solid organ transplant recipients (SOTRs) who received tixagevimab/cilgavimab for pre‐exposure prophylaxis and 222 vaccine‐matched solid organ transplant recipients who did not receive tixagevimab/cilgavimab. Breakthrough SARS‐CoV‐2 infections occurred in 11 (5%) of SOTRs who received tixagevimab/cilgavimab and in 32 (14%) of SOTRs in the control group (p < .001). In the tixagevimab/cilgavimab group, SOTRs who received the 150–150 mg dose had a higher incidence of breakthrough infections compared to those who received the 300–300 mg dose (p = .025). Adverse events were uncommon, occurring in 4% of our cohort and most were mild. There was no significant change in serum creatinine or liver chemistries in kidney and liver transplant recipients, respectively. In conclusion, we found that tixagevimab/cilgavimab use is safe and associated with a lower risk of breakthrough SARS‐CoV‐2 infection in vaccinated solid organ transplant recipients during the Omicron wave.