Cristina Moracas

Purpose: Elevated transaminases have been associated with increased severity in adult influenza cases, but data in the pediatric population are limited. This study aims to evaluate the prevalence, clinical characteristics and prognostic value of elevated transaminases in children hospitalized for influenza. Methods: A multicentre retrospective cohort study was conducted on 543 children hospitalized for acute viral respiratory infections. Demographic, clinical, biochemical, radiological features, and outcome were collected and analyzed, comparing children with influenza to those with other respiratory viruses. The association between elevated transaminases and clinical severity, complications, and intensive care unit (ICU) admission was assessed. Results: Among 543 children, 127 (23.4%) had laboratory‐confirmed influenza, with 24.4% showing elevated transaminases versus 7.2% in noninfluenza infections ( p < 0.001). Influenza B was associated with a higher prevalence of hypertransaminasemia (40%) than influenza A (20.6%, p = 0.042). Asthenia, myalgia, and hypovolemic shock were more common in the elevated transaminase group ( p < 0.05). Biochemical markers indicated muscular rather than hepatic origin of hypertransaminasemia. Elevated transaminases correlated with length of hospital stay (10.2 vs. 5.8 days, p < 0.001), ICU admission (OR 4.4, p = 0.035), high‐flow oxygen need (OR 4.6, p = 0.005), and intravenous fluids (OR 6.2, p = 0.001). Two deaths occurred, both in the elevated transaminase group. Conclusion: Elevated transaminases occur in one fourth of children hospitalized for influenza and are associated with more severe disease, systemic complications, and worse outcomes. The findings suggest that transaminase elevation reflects systemic and muscular involvement rather than primary liver injury. Monitoring transaminases provides an early, easy marker to identify children at risk of severe influenza.

We introduce PerTexP (Pertussis Time Exploration), an interactive modelling tool designed to investigate pertussis transmission dynamics and to support the evaluation of vaccination strategies and short-term projections. PerTexP allows users to explore and compare maternal, infant, and non–infant booster vaccination scenarios and to assess their potential impact on disease transmission, with a particular focus on the Italian epidemiological context. The tool is based on a discrete-time, stage–structured compartmental model with two age classes. By enabling rapid scenario-based analyses, PerTexP supports evidence-informed decision-making and provides transparent insights into how alternative vaccination strategies may shape pertussis dynamics. Combining accessibility, flexibility, and methodological rigour, PerTexP offers a practical resource for researchers and public health practitioners interested in exploring and comparing pertussis control strategies.

Background: Pertussis has re-emerged in Europe since late 2023, representing a major public health concern and a significant cause of morbidity and mortality among infants. Macrolide antibiotics clarithromycin and azithromycin are recommended as first-line therapy; however, their comparative efficacy in infants remain poorly characterized. Methods: We conducted a multicenter retrospective cohort study emulating a target trial to assess the real-world effectiveness of macrolide therapy in infants hospitalized for pertussis across eleven Italian centres between November 2023 and December 2024. Infants received either azithromycin or clarithromycin according to clinical judgment. The primary outcome was a severe disease course, defined as a Pertussis Severity Score (PSS) >5. Secondary outcomes included intensive care unit (ICU) admission, need for oxygen therapy, complications, length of stay, 30-day readmission, and mortality. Confounding was addressed using propensity score methods with overlap weighting. Findings: Among 194 infants included (89 males [45·9%], median age 3 months [IQR 1·5–4·0]), 145 (74·7%) received clarithromycin and 49 (25·3%) received azithromycin. Baseline characteristics and disease severity at admission were comparable between groups, and no antibiotic-related adverse events were observed. In propensity score–weighted analyses, azithromycin was associated with a higher risk of severe disease compared with clarithromycin (PSS >5: 61·2% vs 33·1%; odds ratio [OR] 1·80, 95% CI 1·04–3·34), and with an increased need for oxygen therapy (42·9% vs 17·9%; OR 1·95, 95% CI 1·07–3·53). Severe complications were more frequent in azithromycin group (14·3% vs 2·1%; p=0·021), as ICU admission (24·5% vs 0·7%; p=0·032). Two deaths occurred, both in the azithromycin group. Covariate-adjusted sensitivity analyses yielded consistent and more pronounced associations. Interpretation: In this observational study emulating a target trial, clarithromycin was associated with more favorable clinical outcomes than azithromycin among infants hospitalized with pertussis. Large prospective randomized trials are warranted to confirm these observations and better guide clinical recommendations.