Vaccination Coverage in Hematopoietic Stem Cell Transplant Patients

<b>Background/Objectives</b>: Patients undergoing hematopoietic stem cell transplantation (HSCT) experience profound immunosuppression, increasing their risk of infections. Revaccination is essential to reduce morbidity and mortality. This study aimed to evaluate post-transplant vaccination coverage among patients treated at a specialized reference center. <b>Methods</b>: We conducted a cross-sectional, retrospective study including patients who underwent HSCT between 1 January 2018 and 31 May 2021. Vaccination coverage was assessed for each recommended vaccine, and full compliance was defined according to the Spanish Ministry of Health guidelines. A competing risk survival analysis was performed to account for loss to follow-up due to death. Data analysis was carried out using STATA v15. <b>Results</b>: Among 138 included patients, 22.46% (31/138) died, and 11.59% (16/138) relapsed. Of the 107 patients who remained in follow-up at 19 months, 41.12% (44/107) (95% CI: 32.26-50.59) had completed the full vaccination schedule, while only 1.87% (2/107) (95% CI: 0.51-6.56) achieved temporal compliance. No significant association was observed between sex and vaccination status or competing risks (<i>p</i> > 0.05). <b>Conclusions</b>: Post-HSCT vaccination coverage remains suboptimal, highlighting the need for improved vaccination programs, multidisciplinary patient support, and enhanced public and professional awareness to ensure timely immunization in this high-risk population.