LAUSR

To the editor, Patients receiving solid organ transplantation (SOT) are at an increased risk of mortality and morbidity attributed to coronavirus disease 2019 (COVID19).[1] Severe acute respiratory syndrome coronavirus 2 (SARSCoV2) vaccination reduces the risk of severe disease and death.[2] Several studies have shown a lack of vaccine response in liver transplantation (LT) recipients after two or three doses of the vaccine.[3] Predictors for a negative response among LT recipients include older age, lower glomerular filtration rate, and treatment with mycophenolate mofetil (MMF).[4] The rate of protection in SOT recipients after three doses of the vaccine remains insufficient. For these patients, prophylactic infusion of monoclonal anti– SARSCoV2 antibodies can be offered, although we have less insight regarding the longterm efficacy when compared with the vaccines. The immunosuppression regimen classically administered to LT recipients is a combination of tacrolimus and MMF.[5] However, in various situations, MMF can be stopped or discontinued without increasing the risk of acute graft rejection, especially in lowrisk patients. In this study, we aimed to evaluate the impact of a temporary discontinuation of MMF on vaccine response after a fourth dose of vaccine in nonresponding LT recipients.