Inclusion Criteria:  Kidney transplant recipients Recipient age ≥ 18 years Written Informed Consent and Consent for Processing Personal Data Vaccination with two doses of SARS-CoV-2 mRNA vaccine either before or after kidney transplantation.  Exclusion Criteria:  Active SARS-CoV-2 infection. Patients that received anti-SARS-CoV-2 monoclonal antibodies. Active infection after vaccination Monoclonal antibodies treatment ahead of antibody or cellular immunity screening