LAUSR

or mRNA-1273) was therefore determined by the vaccination progress in our kidney transplant cohort and vaccine availability at that time. A two-dose vaccination regimen was applied, with 3-weeks (BNT162b2) and 4-weeks (mRNA-1273) intervals between the fi rst and second vaccination, regardless of a history of prior infection with SARS-CoV-2. Anti-SARS-CoV-2-antibodies directed against the receptor binding domain (RBD) of the S1 subunit of the Spike (S) protein were measured with the SARS-CoV-2 IgG II Quant assay (Abbott Ireland Diagnostics Division, Finisklin Business Park, Sligo, Ireland), which was reported to have high sensitivity and speci fi city for detection of anti-SARS-CoV-2 S-protein antibodies (5) and high correlations with anti-SARS-CoV-2 neutralizing antibodies (6). Results were reported in BAU/ml (binding antibody units). Differences between vaccine groups (mRNA-1273 vs BNT162b2) in S-antibody-positivity were tested for statistical signi fi cance using the Chi 2 -Test. To further investigate the impact of vaccine type on S-antibody-positivity, we computed a multivariate logistic regression model taking potential confounding factors of seroconversion after SARS-COV2 vaccination into account. Results are reported as odds ratios (OR) and 95% con fi dence intervals (95% CI). We performed a complete case analysis as covariate information was missing in one patient only for the multivariate model. The study was approved by the Ethics Committee of the (ID: 1100/2021). Patients provided written informed consent. Patient demographics and additional analyses are shown in the Supplementary Material