Gül Arga

Aim: The aim of this study was to evaluate the risk factors for CMV reactivation and the effects of CMV on HSCT outcomes in patients managed using a standard prophylaxis and preemptive treatment approach in settings where letermovir prophylaxis could not be used. Methods: Patients who underwent HSCT between January 2006 and December 2023 in our pediatric hematology department were included in this retrospective study. Results: Among 217 patients included, 96 (44.4%) underwent HSCT for malignant diseases. The donor was a matched‐sibling for 65.4%, and 86.1% had myeloablative conditioning regimen. All patients received acyclovir prophylaxis (1500 mg/m ² /day) for the first 30 days. The prevalences of acute and chronic GVHD were 28.1% and 18%, respectively. In a median (IQR) follow‐up of 49 (26.5–93.3) months, 60 (27.6%) patients experienced a total of 92 CMV reactivations. Patient group that experienced CMV reactivations was characterized by higher rates of malignant diseases, higher rates of mismatched donors, lower rates of bone marrow as stem cell source, higher acute and chronic GVHD prevalences, and higher grades of acute GVHD. In the group that did not experience CMV reactivation, 2‐year overall survival rates were higher and treatment‐related mortality rates were lower. This association remained consistent when evaluated among non‐malignant patients. However, no significant difference was observed in the malignant diseases. Conclusion: After an effective prophylaxis, CMV DNA monitoring combined with preemptive treatment have an important role in CMV management. However, the survival rates among patients experiencing CMV reactivation remain lower. image

Background: Cytomegalovirus (CMV) remains a frequent infectious complication after pediatric liver transplantation despite antiviral prophylaxis. However, the clinical significance of CMV DNAemia and predictors of treatment-requiring CMV DNAemia remain incompletely defined. We evaluated the epidemiology, timing, clinical characteristics and predictors of CMV DNAemia in pediatric liver transplant recipients managed with a hybrid prevention strategy. Methods: We conducted a retrospective cohort study of consecutive pediatric liver transplant recipients who underwent transplantation between 2014 and 2025 at a tertiary center. CMV DNAemia was identified through routine quantitative polymerase chain reaction surveillance during antiviral prophylaxis and the subsequent preemptive monitoring period. Treatment-requiring CMV DNAemia was defined as CMV DNAemia prompting antiviral therapy based on viral load kinetics, absolute viral load and accompanying clinical findings. Demographic, transplant-related, clinical and virological factors were analyzed. Results: Fifty-one recipients were included. CMV DNAemia developed in 35 recipients (68.6%), accounting for 77 episodes. Breakthrough CMV DNAemia occurred in 22 recipients (62.8%), whereas 13 developed CMV DNAemia only after prophylaxis discontinuation. Twenty-eight episodes occurred during prophylaxis, but only 7 (25.0%) required treatment. Overall, 15 recipients experienced 25 treatment-requiring episodes, representing 32.5% of all CMV DNAemia episodes; 72% occurred after prophylaxis discontinuation. No patient developed tissue-invasive CMV disease. Younger age at transplantation (OR: 0.979; 95% CI: 0.963–0.995; P = 0.013) and pretransplant intensive care unit requirement (OR: 7.75; 95% CI: 1.44–41.84; P = 0.017) independently predicted treatment-requiring CMV DNAemia. An age threshold of ≤26 months showed acceptable discrimination (area under the curve, 0.773) and was associated with lower CMV-free survival ( P < 0.001). Conclusions: CMV DNAemia was common, but only one-third of episodes required antiviral treatment, and no tissue-invasive disease occurred. Younger recipients and those requiring pretransplant intensive care were at increased risk for clinically significant CMV infection. CMV DNAemia alone should not be considered a surrogate for clinically significant infection, supporting individualized, risk-adapted surveillance and prevention in pediatric liver transplant recipients.

Invasive meningococcal disease (IMD) remains a major cause of morbidity and mortality in children. Post-pandemic epidemiological patterns of pediatric IMD are not well defined in Türkiye. This study aimed to evaluate the epidemiology, clinical characteristics, outcomes, and serogroup distribution of pediatric IMD in a large multicenter cohort in Türkiye, comparing the during-COVID and post-COVID periods. This retrospective multicenter hospital-based study included children aged 1 month–18 years hospitalized with laboratory-confirmed IMD in 39 hospitals across 23 provinces. Cases were grouped as during-COVID (January 2020–May 2022) and post-COVID (June 2022–December 2025). A total of 166 patients (median age 25 months; 59.6% male) were included; 25 occurred during-COVID and 141 post-COVID. The number of reported cases in participating centers increased after 2022, with seasonal peaks in winter and early spring. Children under 5 years accounted for 62.7% of cases, and infants (< 1 year) were the largest single age group overall (38.6%). The proportion of children under 5 years was lower in the post-COVID period (58.9% vs 84.0%; OR 0.27, 95% CI 0.09–0.84), indicating a relative shift toward older age groups rather than a reduction in disease burden among infants. Pediatric intensive care admission occurred in 69.9% of cases, and overall mortality was 13.3%. Mortality varied markedly by clinical form, from 1.2% in meningitis alone to 21.7% in combined meningitis and meningococcemia and 38.1% in meningococcemia alone (p < 0.001). Only 2.4% of children had received any meningococcal vaccine before their illness. Serogroup data were available for 60.8% of patients, with grouping coverage differing between periods (32.0% vs 66.0%). Among cases with available serogroup data, serogroup B accounted for 69.9% in the post-COVID period and for half of the eight grouped cases during the pandemic. In unadjusted exploratory analysis restricted to cases with serogroup data, mortality was higher in serogroup B than non-B infections (21.7% vs 3.1%; OR 8.61, 95% CI 1.08–68.8); in an exploratory model adjusting for clinical form, age, and period, with ungrouped cases retained as a separate category, serogroup B remained associated with mortality (aOR 7.59, 95% CI 1.55–75.65). Conclusion: In this multicenter hospital-based cohort, reported pediatric IMD cases increased in the post-pandemic period, with a persistent burden in infants, a relative shift toward older age groups, and predominance of serogroup B among grouped cases. These findings highlight the importance of strengthened surveillance and support further evaluation of meningococcal vaccination strategies, including MenB vaccination. What is Known: • Invasive meningococcal disease remains a severe pediatric infection with high morbidity and mortality, despite treatment. • The COVID-19 pandemic and the subsequent easing of restrictions altered IMD epidemiology globally. What is New: • Reported pediatric IMD cases increased in the post-pandemic period, with a relative shift toward older children while the proportion of infants remained unchanged (38.3% vs 40.0%); serogroup B predominated among cases with an available serogroup result, although differential availability of these data precludes conclusions about change over time. • Mortality was determined principally by clinical form, ranging from 1.2% in meningitis alone to 38.1% in meningococcemia alone, and only 2.4% of children had received any meningococcal vaccine before their illness.

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Pertussis resurged globally, after the relaxation of COVID-19 measures, underscoring its continued relevance as a public health concern, yet data remain li