Background: HSCT patients are at an increased risk of developing infections after transplant due to the loss of immunogenicity from prior vaccinations. Current national and international guidelines recommend routine revaccinations at a fixed dosing schedule for HSCT patients post-transplant. Although immunization adherence is vital to prevent infections, compliance with post-transplant vaccinations is unknown. The primary endpoint of this study was the completion rate of the post-transplant vaccination series. Secondary endpoints included identifying reasons for non-compliance, rates of breakthrough vaccine-preventable infections, and assessing post-vaccination antibody responses based on titers.
Methods: A single-center, retrospective study of adult HSCT patients at Yale New Haven Hospital between January 2010 and September 2015 was performed. Patients were excluded if: <18 years of age, deceased prior to one year post-transplant, transferred care to an outside facility, or were lost to follow-up.
Results: A total of 512 HSCT patients were evaluated. 390 (76%) patients were initiated on the vaccination series. Of the 390 patients, 275 (71%) patients were started at one year follow-up per institutional guidelines. The most common reasons for non-initiation or delayed initiation of the vaccine series included disease relapse (14%), active graft versus host disease (9%), and the need for immunosuppressive therapy (5%). Of the patients initiated on the vaccination series, only 187 (48%) patients completed the entire vaccination series; with the majority of whom were autologous HSCT patients (72%). The most common reasons for an incomplete vaccination series included maintenance chemotherapy (19%), disease relapse (16%), and lost to follow-up (10%). Of the patients who completed the vaccination series, 19% had the appropriate post-vaccination titers obtained. Of the patients who received at least one or more doses of pneumococcal vaccine post-transplant, 8 patients (2%) developed a breakthrough infection with S. pneumoniae.
Conclusion: This study adds important data to the limited body of literature on HSCT vaccine compliance rates. Future studies on the best interventions to improve compliance rates are warranted.
D. McManus, None
F. Foss, None
I. Isufi, None
S. Seropian, None
J. Topal, None