Incidence and Clinical Outcomes of Multiple Viral Infections After Allogeneic Hematopoietic Cell Transplantation

Recipients of allogeneic hematopoietic cell transplantation (alloHCT) are at risk of multiple viral infections. However, our knowledge about the clinical impact of viruses following alloHCT is predominantly focused on outcomes of a single viral infection such as cytomegalovirus (CMV). This retrospective cohort study aimed to evaluate the incidence, risk factors, and clinical outcomes of multiple viral infections in the first year following alloHCT.

All microbiologically confirmed viral infection of CMV, Epstein-Barr virus (EBV), BK polyomavirus (BKV), varicella zoster virus, human herpesvirus 6, herpes simplex virus, and various respiratory viruses were reviewed up to 12 months post-alloHCT.

Among 430 alloHCT recipients, 744 viral infections were observed within the first year posttransplantation, predominantly CMV (55%), followed by EBV (51%) and BKV (21%). Eighty-five percent of patients had at least 1 viral infection, of which 34% had 2 and 24% had ≥3 viruses. Independent risk factors of multiple viral infections included CMV serostatus (R⁺/D^-: hazard ratio [HR], 2.59 [95% confidence interval {CI}, 2.03-3.30]; R^-/D⁺: HR, 2.25 [95% CI, 1.66-3.05]), haploidentical donor (HR, 1.56 [95% CI, 1.18-2.06]), T-cell depletion use (HR, 1.44 [95% CI, 1.11-1.88]), and grade III-IV acute graft-versus-host disease (HR, 1.44 [95% CI, 1.15-1.80]). Patients experiencing multiple viral infections (≥3 vs 2 vs 1) had an earlier time to onset of first infection (median, 18 vs 25 vs 40 days), were hospitalized for an increased number of days (median, 53 vs 40 vs 37 days), and had lower survival probability at day 270 following infusion (P = .044).

Multiple viral infections were frequently observed, with a significant impact on morbidity and mortality following alloHCT.