In children scheduled to undergo allogeneic hematopoietic stem cell transplantation (HSCT) who test positive for viral respiratory infection, delaying transplant until the virus is cleared may improve outcomes, according to study results published in the British Journal of Haematology.

In this retrospective study, researchers analyzed records of all children who underwent allogeneic HSCT in the Bone Marrow Transplantation Unit at Great Ormond Street Hospital for Children in London between November 2007 and November 2017. Viral respiratory infections were monitored before and after transplant using nasopharyngeal aspirates. The researchers assessed the effect of a positive nasopharyngeal aspirate on clinical outcomes after allogeneic HSCT.

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During the study period, 585 children underwent allogeneic HSCT. Of 75 patients who had a positive nasopharyngeal aspirate, 33% (25/75) had their transplant delayed, while the remaining patients began conditioning with a viral respiratory infection.

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After HSCT, patients who had a positive nasopharyngeal aspirate had significantly lower overall survival (54% vs 79%) and higher transplant-related mortality (26% vs 7%) compared with patients who had a negative nasopharyngeal aspirate. Improved overall survival (90.5%) and lower transplant-related morality (5%) were documented for patients with a positive nasopharyngeal aspirate who had delayed transplant and cleared the virus before HSCT.

A positive nasopharyngeal aspirate before HSCT was the only significant risk factor for progression to a lower respiratory tract infection (odds ratio [OR], 3.1; 95% CI, 1.3-6.0; P <.01) and was a major risk factor for 100-day transplant-related mortality (OR, 4.8; 95% CI, 2.4-9.8; P <.001).

The researchers concluded that “screening for viral respiratory infections prior to transplant is of paramount importance, as outcomes are dismal when patients are transplanted with a positive nasopharyngeal aspirate screen” and that “transplant delay, whenever feasible, in case of a positive nasopharyngeal aspirate screen for viral respiratory infections can positively affect survival of children undergoing HSCT.”


1.     Ottaviano G, Lucchini G, Breuer J, et al. Delaying haematopoietic stem cell transplantation in children with viral respiratory infections reduces transplant-related mortality [published online September 30, 2019]. Br J Haematol. doi:10.1111/bjh.16216