Exploring vaccination adherence and its determinants in kidney transplant recipients: insights from a large italian transplant centre

Abstract Background Vaccine-preventable infections are a major cause of morbidity and mortality among kidney transplant recipients, yet real-world adherence to recommended vaccination schedules remains poorly characterised. We aimed to assess adherence to the full vaccination schedule and identify its independent predictors in a large Italian cohort. Methods Single-centre retrospective cohort study of consecutive adult kidney transplant recipients at the University Hospital of Padua (Veneto, Italy), 2013–2024. Adherence was assessed on the regional immunisation registry data and quantified using a composite vaccination adherence score encompassing up to ten vaccines according to patient-specific elegibility ranging from 0 (adherent to no vaccination) to 1 (adherent to all vaccinations). Determinants were analysed by fractional logit regression (quasi-binomial GLM, logit link, HC1 robust standard errors); sensitivity analyses excluded influential observations by Cook’s distance. Results Among 784 recipients (mean age 52.9 ± 12.3 years; 63.7% male), median adherence score was 0.25 (IQR 0.13–0.44) and only 11 patients (1.4%) were fully adherent. Per-vaccine adherence was highest for COVID-19 (87.4%) and HBV (61.9%), and lowest for Hib (7.9%), MenB (9.0%), HPV (13.1%), and RZV (13.8%). In the multivariable model, transplant in 2023–2024 (aOR 1.53, 95%CI 1.25–1.89; p < 0.001) and older age (aOR 1.01/year, 95%CI 1.00–1.02; p = 0.030) were independently associated with higher adherence, whereas unknown underlying renal pathology (aOR 0.77, 95% CI 0.62–0.96; p = 0.02) and re-transplantation (aOR 0.73, 95%CI 0.56–0.95; p = 0.02) predicted lower adherence. Findings were robust in sensitivity analyses. Conclusions Vaccination adherence was suboptimal, with patients with unknown renal pathology representing a particularly vulnerable subgroup. Temporal improvement closely aligned with regional guideline publication suggests that structured guideline implementation can meaningfully improve adherence.