Antibody response to non-mRNA SARS-CoV-2 vaccine in kidney transplant recipients

Background: Kidney transplant recipients (KTRs) show poor antibody response to the SARS-CoV-2 vaccine. There is limited data on immune response to non-mRNA vaccines in KTRs. We studied the antibody response to the SARS-CoV-2 non-mRNA vaccine in a cohort of kidney transplant recipients. Methods: We included KTRs following up in the tertiary care transplant outpatient clinic from February to April 2022. SARS-CoV-2 spike protein IgG antibody titers were measured using chemiluminescence immunoassay. Data on demographic, clinical, and laboratory characteristics were collected, and patients were characterized by the history of Coronavirus disease 2019 (COVID-19) infection in the past and the number of vaccine doses received. Predictors of antibody response were obtained using multivariate regression analysis. Results: S1/S2 IgG anti-SARS-CoV-2 antibodies were detected in 197 (87.94%) of 224 KTRs with a median [IQR] titers of 307.5 AU/ml [91 AU/ml - 400 AU/ml]. Neutralizing range antibody titers were found in 170/224 (75.9%) KTRs. Diabetes at the time of vaccination was associated with poorer antibody response (aOR 0.31, 95% confidence interval [CI] - 0.10, 0.90; p = 0.032) and vaccination with CovishieldTM (ChAdOx1 nCoV- 19 Recombinant CoronaVirus Vaccine) showed higher antibody response as compared to CovaxinTM (BBV152) (aOR 5.04, 95% CI - 1.56, 16.22; p = 0.007). Graft dysfunction at baseline was associated with poorer antibody response. Conclusions: KTRs showed good antibody response after SARS-CoV-2 vaccination with non-mRNA vaccines. Diabetes and graft dysfunction were associated with poor seroconversion rates.