Burden of Vaccine-Preventable Infections Among Pediatric Hematopoietic Cell Transplant Recipients

Abstract

<h3>Background</h3> Hematopoietic cell transplantation (HCT) recipients are increased risk for vaccine-preventable infections (VPI). However, the true prevalence of VPI in children post-HCT is unknown. <h3>Methods</h3> We performed an epidemiological study using the Pediatric Health Information System (PHIS) database in children and young adults who underwent allogeneic (allo) and autologous (auto) HCT and had a first hospitalization with a VPI (as defined by ICD-9 and ICD-10 codes) within 5-yr post-HCT between Jan 1, 2010 and Dec 31, 2018 at the 45 participating US PHIS hospitals. Prevalence for overall VPI and by infection were calculated at the following timepoints: at initial HCT admission, HCT discharge to D100, D101-D180, 6-12 months, 1-2 yr, and 2-5 yr post-HCT. <h3>Results</h3> We identified 9,591 unique HCT recipients (alloHCT: 6,602, 69%; autoHCT: 2,989, 31%) with a median age of 6.7 years (range infant-18.9 yrs) during the 8-yr study period. Of these, 684 HCT recipients (510 alloHCT, 174 autoHCT) were hospitalized with VPI in the first 5 yrs after HCT, for an overall prevalence of 7.1%. VPI occurred more frequently among alloHCT (8%) than autoHCT recipients (6%) at all time-points (p=0.0008). VPI hospitalizations occurred a median of 221 days post-HCT [range 0-5 yrs] with the majority occurring in the first 6-12 mos post-HCT (Figure 1). Influenza was the most frequent VPI (4.05%) (Table I). <h3>Conclusion</h3> The overall prevalence of VPI hospitalizations after pediatric HCT was 7.1%, occurring most frequently in the first 6-12 months post HCT and among alloHCT recipients. Continued efforts to prevent VPI, including optimizing vaccination strategies in this population, are warranted.