Kidney transplant recipients are at increased risk of infections, including Varicella-zoster virus (VZV) infections. Vaccination against VZV is routinely offered to all kidney transplant recipients and candidates in Denmark. In this exploratory observational study, the VZV specific immune response in kidney transplant candidates and recipients will be characterized at different time points in relation to transplantation, vaccination and infections. More knowledge on the immune reaction to transplantation, VZV vaccination and VZV infections may provide improved strategies for prevention and treatment of VZV infections in kidney transplant candidates and recipients.