Viral infections are a major cause of morbidity and mortality in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT), particularly during the first 100 days post-transplant, a period of profound immunosuppression. Data on their prevalence and kinetics in low- and middle-income countries, including Morocco, remain limited. This study aimed to evaluate these infections at the Children’s Hospital in Rabat. We conducted a retrospective descriptive study of pediatric patients who underwent HSCT at the Children’s Hospital in Rabat from January 2018 to June 2025. Post-transplant viral monitoring included weekly quantitative PCR for cytomegalovirus (CMV) and Epstein–Barr virus (EBV) until day 100. Targeted PCR for adenovirus, BK virus, HHV-6, and respiratory viruses was performed in symptomatic patients. Out of 33 patients, CMV was the most frequently detected agent, with an incidence of 51,5% ( n = 17), of which 30.3% had a viral load > 2.5 log₁₀ IU/ml. The median time to first reactivation was 3 weeks (IQR: 2–6). The vast majority of episodes occurred in seropositive (R+) recipients, mainly D+/R+. The highest viral loads were observed in patients with CMV viremia temporally associated with pulmonary involvement (2.62 log₁₀ IU/ml IQR: 0.00–3.42) compared to those without pulmonary involvement (0.00 log₁₀ IU/ml IQR: 0.00–2.04; p = 0.007), despite the absence of virological confirmation of CMV-related pulmonary disease. Similarly, patients with gastrointestinal (GI) complications had higher viral loads (3.13 log₁₀ IU/ml IQR: 2.23–3.89) compared with those without GI involvement (0.00 log₁₀ IU/ml IQR: 0.00–2.04, p = 0.002). Concerning EBV, viral loads showed transient reactivations, fluctuating between quantifiable and undetectable, mainly between the 1st and 7th week post-transplant. Infections were more frequent in recipients who were initially seronegative (D+/R−) included 8 of 13 patients (61.5%), No cases of post-transplant lymphoproliferative disease were reported. BK virus showed an early peak of infection between the 1st and 4th week, strongly associated with the occurrence of hemorrhagic cystitis, highlighting its significant clinical impact during this period. This study highlights the particularly early kinetics of CMV, BK virus, and EBV in our pediatric patients after HSCT, with CMV appearing around week 3, transient EBV reactivations in initially seronegative patients, and an early BK virus peak linked to hemorrhagic cystitis.
Hassaine et al. (Wed,) studied this question.