Background: Respiratory syncytial virus (RSV) is a leading cause of hospitalization in children, but predictors of critical illness remain poorly defined. This study aimed to identify risk factors for critical RSV pneumonia and to develop a predictive model. Methods: A retrospective analysis of 12,035 hospitalized children with RSV infection (2019-2025) yielded 304 eligible patients after exclusions. Based on critical illness criteria, 30 critical cases and 90 randomly selected non critical controls from the remaining patients were enrolled. Clinical characteristics, laboratory parameters, and co-infection patterns were compared. Univariate, Lasso, and multivariable logistic regression analyses were performed to identify independent predictors, which were then incorporated into a nomogram. Model performance was assessed using ROC curve, calibration plot, and decision curve analysis. Results: Among the 304 eligible children, 30 (9.9%) had critical illness. Co infection with three or more pathogens was most common in the critical group (43.3%), whereas single RSV infection predominated in the non critical group (38.9%). Multivariable logistic regression identified four independent predictors of critical illness: interleukin 6 (IL 6), creatine kinase MB (CK MB), serum bilirubin excretion (SBE), and neutrophil percentage. The nomogram combining these factors exhibited excellent discriminative ability (AUC = 0.921, 95% CI: 0.868-0.974). The calibration curve agreed well with the 45° reference line (Hosmer-Lemeshow χ² = 3.233, p = 0.919), and decision curve analysis demonstrated clinical benefit across threshold probabilities ranging from 0.01 to 0.99. Conclusions: Elevated IL-6, CK-MB, neutrophil percentage, and SBE are independent predictors of critical RSV infection in children. The nomogram based on these readily available biomarkers provides a robust tool for early risk stratification and clinical decision-making.

Background: Reducing unnecessary antibiotic exposure is a major priority in pediatric antimicrobial stewardship. The comparative effectiveness of short-course versus standard- or longer-course oral antibiotic therapy for uncomplicated bacterial infections in children remains uncertain. Objective: To evaluate whether short-course oral antibiotic therapy increases clinical treatment failure compared with standard- or longer-course therapy in children with uncomplicated bacterial infections, with a primary focus on same-antibiotic pediatric pneumonia/lower respiratory tract infection (LRTI) trials. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials. MEDLINE/PubMed, Embase, Web of Science, and CENTRAL were searched, supplemented by citation searching and trial registry review. Eligible studies enrolled children aged 0–18 years with uncomplicated bacterial infections treated with oral antibiotics in outpatient or ambulatory settings. The primary outcome was clinical treatment failure; broader pneumonia/LRTI and all-infection analyses were treated as sensitivity or exploratory analyses. Random-effects meta-analysis used risk ratios (RRs) and risk differences (RDs) with 95% confidence intervals (CIs). Risk of bias was assessed with the Cochrane risk-of-bias tool. The review was registered in PROSPERO (CRD420261339263). Results: Fourteen randomized trials were included; nine same-antibiotic pneumonia/LRTI comparisons contributed to the primary pooled analysis. Short-course therapy was not associated with increased treatment failure (RR, 1.01; 95% CI, 0.92–1.11; I ² = 0.0%), and the absolute-effect analysis showed no meaningful difference (RD, 0.001; 95% CI, −0.010 to 0.013; I ² = 10.0%). A broad pneumonia/LRTI sensitivity analysis including different-antibiotic comparisons was also non-significant (RR, 0.94; 95% CI, 0.66–1.33) but heterogeneous. The all-infection exploratory analysis was similarly non-significant (RR, 0.89; 95% CI, 0.63–1.25) and interpreted cautiously given clinical heterogeneity. Of the 14 trials, 5 were at low risk of bias, 2 had some concerns, and 7 were at high risk. Conclusion: In same-antibiotic pediatric pneumonia/LRTI trials, short-course therapy was not associated with increased clinical treatment failure compared with standard- or longer-course therapy. Broader analyses across different antibiotic strategies and infection syndromes did not materially change this interpretation but showed substantial heterogeneity. These findings support cautious, infection-specific antibiotic duration reduction rather than broad generalization across all uncomplicated pediatric bacterial infections. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261339263 , identifier CRD420261339263.

Background/Objectives: Respiratory syncytial virus (RSV) is a leading cause of hospitalization in children, but predictors of critical illness remain poorly defined. This study aimed to identify risk factors for critical RSV pneumonia and develop a predictive model. Methods: A retrospective analysis of 12,035 children hospitalized with RSV infection between 2019 and 2025 identified 304 eligible patients after applying exclusion criteria. Among these, 30 children with critical illness and 90 randomly selected non-critical controls were included. Clinical characteristics, laboratory parameters, and co-infection patterns were compared. Univariate, Lasso, and multivariable logistic regression analyses were performed to identify independent predictors, which were then incorporated into a nomogram. Model performance was assessed using the ROC curve, calibration plot, and decision curve analysis. Results: Among the 304 eligible children, 30 (9.9%) developed critical illness. Co-infection with three or more pathogens was most frequent in the critical group (43.3%), whereas single RSV infection predominated in the non-critical group (38.9%). Multivariable logistic regression identified four independent predictors of critical illness: interleukin-6 (IL-6), creatine kinase-MB (CK-MB), serum bilirubin excretion (SBE), and neutrophil percentage. The nomogram combining these factors exhibited excellent discrimination (AUC = 0.921, 95% CI: 0.868–0.974). The calibration curve closely matched the ideal 45° reference line (Hosmer–Lemeshow χ² = 3.233, p = 0.919), and decision curve analysis demonstrated clinical benefit across threshold probabilities ranging from 0.01 to 0.99. Conclusions: Elevated IL-6, CK-MB, neutrophil percentage, and SBE are independent predictors of critical RSV infection in children. The nomogram based on these accessible biomarkers provides a robust tool for early risk assessment and guiding clinical decisions.