Abstract Background Recipients of allogeneic haematopoietic cell transplant (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. Methods All microbiologically confirmed viral infection of CMV, Epstein-Barr Virus (EBV), BK-polyomavirus (BKV), Varicella-Zoster Virus, Human Herpesvirus-6, Herpes Simplex Virus and respiratory viruses were reviewed up to 12 months post-alloHCT. Results Among 430 alloHCT recipients, 744 viral infections were observed within first year of transplant, predominantly CMV (55%), followed by EBV (52%) and BKV (21%). 85% 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- HR 2.59, CI 2.03-3.30; R-/D+ HR 2.25, CI 1.66-3.05), haploidentical donors (HR 1.56, CI 1.18-2.06), T-cell depletion use (HR 1.44, CI 1.11-1.88), and Grade III-IV acute graft-versus-host-disease (HR 1.44, 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=0.044). Conclusion Multiple viral infections were frequently observed and this had a significant impact on morbidity and mortality following alloHCT.
Yong et al. (2025) studied this question.