Cytomegalovirus DNAemia After Pediatric Liver Transplantation

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.