Vaccination against SARS CoV-2 appears to be the best strategy today to control the COVID-19 pandemic. The first published studies with Pfizer, Moderna and Astra-Zeneca vaccines show very good vaccine protection in the general population and good short-term tolerance. The efficacy of these vaccines ranges from 62 to 95%, which is particularly remarkable, especially for mRNA vaccines. Nevertheless, these studies do not report the vaccine response in organ transplant patients.

It is known that transplant patients have lower vaccine responses than immunocompetent patients due to some degree of immunosuppression.

Therefore, the investigators are interested in evaluating the vaccine response of organ transplant recipients after vaccination against SARS- CoV-2. For non-responder patients, new strategies can be proposed: 3rd or 4th boost of vaccine or perfusion/injection of antiS monoclonal antibodies. These strategies must be evaluated.

Inclusion Criteria:

• Patient, male or female, adult or child (15 years and older)
• Patient vaccinated against SARS-CoV-2 as part of routine care, and having received the 2 injections
• Solid organ transplant recipient
• Transplantation for more than 3 months

Exclusion Criteria:

• History of anaphylactic shock or known allergy to PEG
• Known history of COVID or positive Covid serology in the 3 months preceding inclusion
• Formal contraindication to an intra-muscular injection
• Impossibility to give the subject informed information (subject in emergency situation, difficulties in understanding the subject, ...)
• Subject under legal protection
• Subject under guardianship or curatorship
• Patient having expressed his opposition to participate

Kidney transplant recipients followed in French transplant centers