BACKGROUND: Clinical risk factors of deficient immune responses to COVID-19 mRNA vaccination in SARS-CoV-2 naive hemodialysis recipients (HDR) have already been identified. Clinical factors influencing hybrid immunity induced by SARS-CoV-2 infection and vaccination in HDR have not been reported.

METHODS: A comprehensive analysis of antibody (Ab) and T cell responses to two doses of BNT162b2 mRNA vaccination was performed in 103 HDR, including 75 SARS-CoV-2 naive and 28 experienced patients, and in 106 healthy controls (HC) not undergoing HD, including 40 SARS-CoV-2 naive and 66 experienced subjects. Clinical risk factors associated with lower humoral and cellular immunity were analyzed in SARS-CoV-2 naive and experienced HDR by univariate and multivariate analyses.

RESULTS: Naive HDR had lower neutralizing and non-neutralizing antibody responses to vaccination than naive HC; lower vaccine responses were correlated with previous transplantation, immunosuppressive treatment, corticosteroid treatment, hypoalbuminemia, older age, hypertension, and negative response to hepatitis B vaccination. In contrast, vaccine responses of SARS-CoV-2 experienced HDR were similar to those of HC and were correlated with time between infection and vaccination and with previous transplantation, but not with the other risk factors associated with lower vaccine responses in naive HDR.

CONCLUSION: COVID-19 vaccine responses are influenced by distinct risk factors in SARS-CoV-2 naive and experienced HDR. These observations have important implications for the understanding of vaccine-induced immunity and for the management of this vulnerable patient population.