1. Measurement of anti-S and anti-N antibodies. SARS-CoV-2 IgG against the S and N protein will be quantitatively measured by chemiluminescent microparticle immunoassay (Architect-I System by Abbott, Sligo, Ireland). 2. Measurement of interferon gamma production. Interferon production by SARS-CoV specific T cells will be measured using the QuantiFERON Sars-CoV-2 kit (Qiagen). 3. Baseline immune status (only in hemodialysis patients). Before vaccination the following parameters are determined: number of lymphocytes, number of CD4 positive lymphocytes, number of CD8 positive lymphocytes, number of CD19 positive lymphocytes, B and T cell memory subsets, protein electrophoresis, C3, C4, total IgG, IgA and IgM.

1. Measurement of anti-S and anti-N antibodies. SARS-CoV-2 IgG against the S and N protein will be quantitatively measured by chemiluminescent microparticle immunoassay (Architect-I System by Abbott, Sligo, Ireland). 2. Measurement of interferon gamma production. Interferon production by SARS-CoV specific T cells will be measured using the QuantiFERON Sars-CoV-2 kit (Qiagen). 3. Baseline immune status (only in hemodialysis patients). Before vaccination the following parameters are determined: number of lymphocytes, number of CD4 positive lymphocytes, number of CD8 positive lymphocytes, number of CD19 positive lymphocytes, B and T cell memory subsets, protein electrophoresis, C3, C4, total IgG, IgA and IgM.