Survey of Herpes Zoster in Kidney Transplant Patients: A Single‐Center Study

OBJECTIVES: Herpes zoster is a frequent complication after kidney transplantation. This study aimed to assess its incidence and associated risk factors in adult kidney transplant recipients. METHODS: We retrospectively reviewed cases of herpes zoster that occurred between April 2013 and March 2023 among 714 adult patients who had previously undergone kidney transplantation. Incidence rates were calculated per 1000 person-years. Patient characteristics were compared between those with and without herpes zoster. Multivariable logistic regression was used to identify independent risk factors. Patients with herpes zoster were categorized into disseminated and localized groups, and their clinical backgrounds were compared. RESULTS: Herpes zoster occurred in 112 patients (15.7%), with an incidence of 22.1 per 1000 person-years. The median age at onset was 51 years, and the median time from transplantation to onset was 7.8 years. Age-specific incidence rates per 1000 person-years were 12.2 (twenties), 24.0 (thirties), 21.7 (forties), 23.9 (fifties), 25.8 (sixties), and 25.3 (≥ seventies). Notably, elevated incidence was evident from the third decade onwards. Independent risk factors included reduced estimated glomerular filtration rate and administration of rabbit anti-lymphocyte antibodies. Among affected patients, 13 cases were disseminated, 94 were localized, and 5 were unclassified. Disseminated cases showed more frequent anti-lymphocyte antibody use. CONCLUSIONS: Herpes zoster was relatively common, even among younger adult kidney transplant recipients. Strong immunosuppression and impaired renal function may increase the risk of herpes zoster and its dissemination.