Respiratory viral coinfections and clinical outcomes in critically ill children with acute lower respiratory tract infections

Abstract

Objective: To characterize the distribution of respiratory viruses, determine the frequency of multiple viral detection, and evaluate the association between viral detection patterns and clinical outcomes in children admitted to a pediatric intensive care unit (PICU) with acute lower respiratory tract infections (LRTIs). Material and Methods: This retrospective observational cohort study included patients admitted to the PICU with LRTIs between September 2022 and December 2024 who underwent multiplex respiratory polymerase chain reaction (PCR) testing using nasopharyngeal specimens. Patients were evaluated according to respiratory panel positivity and viral burden. Demographic characteristics, laboratory findings, respiratory support requirements, length of stay, and mortality were compared. Results: A total of 183 patients were included, with at least one virus detected in 126 (68.9%). Among virus-positive patients, 73 (57.9%) had single viral detection, and 53 (42.0%) had multiple viral detection. The most common viruses among patients with single viral detection were rhinovirus/enterovirus (17.8%), human bocavirus (15.1%), and respiratory syncytial virus (RSV) (15.1%); among those with multiple viral detection, they were rhinovirus/enterovirus (39.6%), RSV (37.7%), and human bocavirus (35.8%). Invasive mechanical ventilation was more frequent in patients with multiple viral detection than in those with single viral detection (52.8% vs. 34.2%, p=0.037), whereas hospital length of stay, PICU length of stay, and mortality did not differ significantly. Although PICU length of stay differed overall across the four viral-burden groups (p=0.029), no post hoc pairwise comparison remained significant after Bonferroni adjustment. Conclusion: Multiple viral detection was common among virus-positive children with LRTIs and was associated with a higher frequency of invasive mechanical ventilation. No significant differences were observed in mortality or length of stay. Although PICU length of stay differed overall across viral-burden groups, pairwise comparisons were not significant; therefore, this finding should be considered exploratory. Larger prospective studies are needed to confirm these findings.