Initiation of Post-Transplant Vaccination Among Allogeneic and Autologous HCT Recipients: A Single Center, Retrospective Quality Improvement Assessment

Abstract

<h3>Introduction</h3> Given the significant morbidity from infection after HCT, guidelines have recommended re-vaccination starting at 6 to 12 months post-tx. Guideline adherence, however, has been varied across institutions. <h3>Objectives</h3> We report on a quality improvement initiative at our BMT center aimed at identifying differences in re-vaccination between allogeneic (alloSCT) and autologous (ASCT) HCT pts. <h3>Methods</h3> We performed an analysis of alloSCT pts at our institution from 2015 to 2017 and ASCT pts from 2017; analysis was done in February 2019. Pts were included in the study if they were alive 12 months post-tx and had not had another HCT after the tx of analysis. Charts were reviewed for administration of PCV13, Tdap or DTaP, HiB, inactivated polio, Hep B, Hep A, and meningococcal vaccines. Initiation of re-vaccination was defined as starting at least three separate vaccination series. The percentage of pts initiated on re-vaccination and the median time to vaccine initiation were compared using the Fisher's exact test and the Mann-Whitney U test, respectively. Incidence of chronic GVHD, use of rituximab within one year post-tx, and CAR-T therapy were evaluated by chart review. Incidence of acute GvHD was collected from The Mount Sinai Acute GvHD International Consortium. <h3>Results</h3> Among HCT pts in 2017, significantly more alloSCT pts were initiated on re-vaccination series than ASCT pts (67.5% vs 37.5%; p = 0.0007), although there was no difference in the median time to vaccine initiation among pts who were initiated (Table 1). Among all pts in the cohort, there were no differences in vaccine initiation based on a history of acute or chronic GVHD in alloSCT pts, nor based on post-tx rituximab use in all pts (Table 1). Seven pts subsequently underwent CAR-T therapy, only one of whom started re-vaccination. <h3>Conclusion</h3> This quality initiative demonstrated that our re-vaccination initiation timing was within guideline recommendations for the majority of alloSCT patients. Our study suggests that ASCT pts may have stronger barriers to re-vaccination, such as maintenance therapies or the presence of outside practitioners. We are now using this assessment to standardize the re-vaccination efforts at our BMT center. Potential barriers to re-vaccination should be further evaluated, including the effect of post-tx treatments such as CAR-T therapy.