Investigation of Kidney Transplant Patients for Antibodies and T-cells After Herpes Virus Vaccination and Infection

Kidney transplantation is a life-saving procedure for patients with kidney failure, and in 2021, 252 kidney transplantations were performed in Denmark. Varicella-zoster virus (VZV) is a vaccine-preventable disease that causes varicella during primary infection and herpes zoster when reactivated later in life. VZV is one of the most common infections after organ transplantation, and kidney transplant recipients have high risk of herpes zoster (annual incidence: 3 per 100). Furthermore, kidney transplant recipients that acquire herpes zoster have high risk of disseminated and severe disease as well as increased risk of post-herpetic neuralgia.

Until 2021, the only available VZV/herpes zoster vaccines in Europe were live vaccines, and live vaccines are contraindicated in immunosuppressed individuals due to the risk of infection with the vaccine strain. However, a new, non-live, recombinant subunit herpes zoster vaccine (Shingrix®) that can be used in immunosuppressed individuals was recently approved and became available in Denmark in October 2021.

The efficacy of Shingrix® in healthy individuals is excellent (90%) both with regard to preventing herpes zoster and post-herpetic neuralgia. However, organ transplant recipients receive high doses of immunosuppressive medication, and information on efficacy and immunogenicity of Shingrix® in immunosuppressed individuals is sparse. One randomized study found the efficacy of the vaccine to be good (68%) in patients after hematopoietic stem cell transplantation. Furthermore, one phase III randomized, placebo-controlled study was conducted in 246 kidney transplant recipients, and the vaccine was found to be safe and to induce antibody responses, but the study was not powered to demonstrate efficacy.

At present, international guidelines recommend vaccination against herpes zoster prior to or after transplantation, but there is no information about the optimal timing of vaccination or duration of the immune response in transplant recipients.

Poor or no antibody response after vaccinations are documented among organ transplant recipients. Vaccination prior to transplantation or early post-transplantation may be of benefit because patients are at the highest risk of infections early post-transplantation due to high load of immunosuppressive therapy, however, this is also the period with the highest risk of non-response to vaccines. It is therefore of great importance, for both individual patients and for society, to determine the optimal timing of vaccination, response rates and duration of protection prior to use of vaccines in organ transplant recipients.