The aim of the study was to analyse the burden of cytomegalovirus (CMV) disease in children undergoing hematopoietic stem cell transplantation (HSCT) and its correlation with all-cause mortality. We performed a retrospective study in children up to 18 years of age who underwent allogeneic HSCT between February 2002 to December 2021 in the pediatric blood and marrow transplantation unit. A total of 1035 patients were included where five hundred forty-three (52.4%) patients underwent matched family donor (MFD) HSCT, 213 (20.5%) underwent matched unrelated donor (MUD) HSCT; 279 (26.9%) underwent haploidentical HSCT (T cell replete in 213 and T cell depleted in 66 patients). CMV reactivation was documented in 258 (24.9% patients). CMV was seen in 39 (7.2%) MFD, 77 (36.1%) MUD, 106 T cell replete (49.7%) and 36 T cell depleted (54.5%) transplants. CMV reactivation was predominantly documented in those where donor and recipient were positive (D + /R +) for CMV serostatus (77%)) prior to HSCT. Overall mortality rate was significantly higher in the CMV positive group (103/258, 39.9%), as compared to the CMV negative group (152/777, 19.6%) (p value = 0.0001). CMV was the direct cause of death in 13/1035 children (1.2%). GvHD as a cause of death was found to be significantly higher among those with CMV (n = 32) as compared to those without CMV (n = 14) (35.6 versus 9%, p value = 0.0001). The incidence of CMV reactivation was noted in 25% of HSCT recipients, and predominantly in haploidentical HSCTs. CMV reactivation was shown to significantly impact all-cause mortality and there was a significantly increased risk of mortality due to GvHD among those with CMV reactivation.
