ABSTRACT
Purpose: Immunosuppression can impair immunological responses after vaccination in kidney transplant recipients (KTR). However, little is known about the effect of the booster dose of COVID-19 vaccination, with BNT162b2, after two doses of ChAdOx-1 and its response especially comparing among KTR with different immunosuppressive regimen. Method(s): KTRs who had stable allograft function with the regimen of calcineurin inhibitor (CNI) reduction (sirolimus, tacrolimus [Ctrough 2-4 ng/mL], prednisolone;group A) and the standard regimen (tacrolimus [Ctrough 4-7 ng/mL], mycophenolate mofetil, prednisolone;group B) were enrolled for two doses of ChAdOx-1 (three months apart) and a booster dose with BNT162b2 (1 month after ChAdOx-1). KTRs who had history of COVID-19, anti-SARS-CoV-2 antibody positive at baseline, and positive for donor specific antibody (DSA) were excluded. The immune response for vaccination was measured by anti-SARS-CoV-2 antibody one month after two doses of ChAdOx-1 and BNT162b2. DSA (Luminex) was measured at one month after BNT162b2. Result(s): Forty KTR were enrolled with mean age of 47.52 +/- 10.86 years old. There were 21 KTR in group A and 19 KTR in group B. The group A has significantly higher anti-SARS-CoV-2 antibody after 2 doses of ChAdOx-1 (502.05 +/- 612.87 BAU/ml and 66.69 +/-143.01 BAU/ml for group A and B, p < 0.05) and after a booster dose of BNT162b2 (10,291.04 +/- 12,803.95 BAU/ml and 1,264.94 +/-1,935.50 BAU/ml for group A and B, p < 0.05). None of KTRs developed DSA after completing all vaccination including the booster dose. Conclusion(s): The KTR with CNI reduction regimen has significantly higher immunologic response to COVID-19 vaccination. The booster dose of COVID-19 vaccination provides significantly improve in immunological response in both standard and CNI reduction regimens. Two doses of ChAdOx-1 and a booster dose of BNT162b2 did not lead to DSA production in both regimens.