Varicella Zoster Virus Infection in Children with Autologous Hematopoietic Cell Transplantation: A Retrospective,Single-Center Study in Korea

Although long-term antiviral prophylaxis is recommended to prevent varicella zoster virus (VZV) infection in seropositive recipients of allogeneic and autologous (auto-) hematopoietic cell transplantation (HCT), studies of VZV infections in pediatric auto-HCT recipients are rare. This study aimed to investigate the incidence and characteristics of VZV infection in pediatric auto-HCT recipients and explore the risk factors of VZV infection and its effect on survival outcomes. This study included all pediatric patients who underwent auto-HCT at Samsung Medical Center, Seoul, Korea, between January 1998 and December 2013. Before 2006, short-term acyclovir prophylaxis was provided until neutrophil engraftment; thereafter, routine prophylaxis was not provided. Patients who developed either herpes zoster or chickenpox within 2 years from transplantation were identified, and a chart review was performed. A total of 413 recipients and 698 auto-HCTs were included. Sixty-one episodes of VZV infections were identified in 54 patients. Fourteen cases of VZV infection (23%; 14 of 61) occurred within 30 days after auto-HCT. The cumulative incidence of the first episode of VZV infection at 2 years after transplantation was 14% (95% confidence interval CI], 7.9% to 22.8%) in all recipients and 9% (95% CI, 1.0 to 26.6) in VZV-seronegative patients. Notably, the VZV infection rate increased with age and the VZV infection rate in patients age 15 to 19 years was almost three times higher than in patients age 0 to 4 years (28% versus 10%; P = .003). However, there was no difference in the VZV infection rate between recipients of single auto-HCT and recipients of tandem auto-HCT. Two patients died of disseminated VZV infection. VZV infection is a considerable risk in auto-HCT recipients with or without short-term prophylaxis. Universal antiviral prophylaxis might be considered, particularly in older children, regardless of VZV serologic results. To our knowledge, this is the largest study of VZV infection in pediatric auto-HCT recipients reported to date.