SARS‐COV‐2 vaccination with BNT162B2 in renal transplant patients: Risk factors for impaired response and immunological implications

Solid organ transplant patients are at a higher risk for poor CoronaVirus Disease‐2019 (COVID‐19)‐related outcomes and have been included as a priority group in the vaccination strategy worldwide. We assessed the safety and efficacy of a two‐dose vaccination cycle with mRNA‐based COVID‐19 vaccine (BNT162b2) among 82 kidney transplant outpatients followed in our center in Rome, Italy. After a median of 43 post‐vaccine days, a SARS‐CoV‐2 anti‐Spike seroprevalence of 52.4% (n = 43/82) was observed. No impact of the vaccination on antibody‐mediated rejection or graft function was observed, and no significant safety concerns were reported. Moreover, no de novo HLA‐donor‐specific antibodies (DSA) were detected during the follow‐up period. Only one patient with pre‐vaccination HLA‐DSA did not experience an increased intensity of the existing HLA‐DSA. During the follow‐up, only one infection (mild COVID‐19) was observed in a patient after receiving the first vaccine dose. According to the multivariable logistic regression analysis, lack of seroconversion after two‐dose vaccination independently associated with patient age ≥60 years (OR = 4.50; P = .02) and use of anti‐metabolite as an immunosuppressant drug (OR = 5.26; P = .004). Among younger patients not taking anti‐metabolites, the seroconversion rate was high (92.9%). Further larger studies are needed to assess the best COVID‐19 vaccination strategy in transplanted patients.