inclusion criteria: 1. age \> 18 years; 2. male or female sex; 3. renal transplant with stable renal function in the last 2 months prior to study inclusion. 4. had received a full schedule of vaccination for sars-cov-2 with mrna1273 vaccine (moderna) and remained seronegative at 2 weeks after the second dose. 5. patient giving written informed consent.

inclusion criteria: 1. age \> 18 years; 2. male or female sex; 3. renal transplant with stable renal function in the last 2 months prior to study inclusion. 4. had received a full schedule of vaccination for sars-cov-2 with mrna1273 vaccine (moderna) and remained seronegative at 2 weeks after the second dose. 5. patient giving written informed consent.

inclusion criteria: age > 18 years; male or female sex; renal transplant with stable renal function in the last 2 months prior to study inclusion. had received a full schedule of vaccination for sars-cov-2 with mrna1273 vaccine (moderna) and remained seronegative at 2 weeks after the second dose. patient giving written informed consent.

inclusion criteria: age > 18 years; male or female sex; renal transplant with stable renal function in the last 2 months prior to study inclusion. had received a full schedule of vaccination for sars-cov-2 with mrna1273 vaccine (moderna) and remained seronegative at 2 weeks after the second dose. patient giving written informed consent.

inclusion criteria: 1. age > 18 years; 2. male or female sex; 3. renal transplant with stable renal function in the last 2 months prior to study inclusion. 4. had received a full schedule of vaccination for sars-cov-2 with mrna1273 vaccine (moderna) and remained seronegative at 2 weeks after the second dose. 5. patient giving written informed consent.

inclusion criteria: 1. age > 18 years; 2. male or female sex; 3. renal transplant with stable renal function in the last 2 months prior to study inclusion. 4. had received a full schedule of vaccination for sars-cov-2 with mrna1273 vaccine (moderna) and remained seronegative at 2 weeks after the second dose. 5. patient giving written informed consent.