Nirsevimab and Hospitalization for RSV Bronchiolitis.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis, resulting in 3 million hospitalizations each year worldwide. Nirsevimab is a monoclonal antibody against RSV that has an extended half-life. Its postlicensure real-world effectiveness against RSV-associated bronchiolitis is unclear. METHODS: We conducted a prospective, multicenter, matched case-control study to analyze the effectiveness of nirsevimab therapy against hospitalization for RSV-associated bronchiolitis in infants younger than 12 months of age. Case patients were infants younger than 12 months of age who were hospitalized for RSV-associated bronchiolitis between October 15 and December 10, 2023. Control patients were infants with clinical visits to the same hospitals for conditions unrelated to RSV infection. Case patients were matched to control patients in a 2:1 ratio on the basis of age, date of hospital visit, and study center. We calculated the effectiveness of nirsevimab therapy against hospitalization for RSV-associated bronchiolitis (primary outcome) by means of a multivariate conditional logistic-regression model with adjustment for confounders. Several sensitivity analyses were performed. RESULTS: The study included 1035 infants, of whom 690 were case patients (median age, 3.1 months; interquartile range, 1.8 to 5.3) and 345 were matched control patients (median age, 3.4 months; interquartile range, 1.6 to 5.6). Overall, 60 case patients (8.7%) and 97 control patients (28.1%) had received nirsevimab previously. The estimated adjusted effectiveness of nirsevimab therapy against hospitalization for RSV-associated bronchiolitis was 83.0% (95% confidence interval [CI], 73.4 to 89.2). Sensitivity analyses gave results similar to those of the primary analysis. The effectiveness of nirsevimab therapy against RSV-associated bronchiolitis resulting in critical care was 69.6% (95% CI, 42.9 to 83.8) (27 of 193 case patients [14.0%] vs. 47 of 146 matched control patients [32.2%]) and against RSV-associated bronchiolitis resulting in ventilatory support was 67.2% (95% CI, 38.6 to 82.5) (27 of 189 case patients [14.3%] vs. 46 of 151 matched control patients [30.5%]). CONCLUSIONS: In a real-world setting, nirsevimab therapy was effective in reducing the risk of hospitalized RSV-associated bronchiolitis. (Funded by the National Agency for AIDS Research-Emerging Infectious Disease and others; ENVIE ClinicalTrials.gov number, NCT06030505.).

Procalcitonin at 12-36 hours of fever for prediction of invasive bacterial infections in hospitalized febrile neonates.

Aim: We aimed to investigate the performance of procalcitonin (PCT) assay between 12 and 36 h after onset of fever (PCT H12-H36) to predict invasive bacterial infection (IBI) (ie, meningitis and/or bacteremia) in febrile neonates. Methods: We retrospectively included all febrile neonates hospitalized in the general pediatric department in a teaching hospital from January 2013 to December 2019. PCT assay ≤ 0.6 ng/ml was defined as negative. The primary outcome was to study the performance of PCT H12-H36 to predict IBI. Results: Out of 385 included neonates, IBI was ascertainable for 357 neonates (92.7%). We found 16 IBI: 3 meningitis and 13 bacteremia. Sensitivity and specificity of PCT H12-H36 in the identification of IBI were, respectively, 100% [95% CI 82.9-100%] and 71.8% [95% CI 66.8-76.6%], with positive and negative predictive values of 14.3% [95% CI 8.4-22.2%] and 100% [95% CI 98.8-100%] respectively. Of the 259 neonates who had a PCT assay within the first 12 h of fever (< H12) and a PCT assay after H12-H36, 8 had IBI. Two of these 8 neonates had a negative < H12 PCT but a positive H12-H36 PCT. Conclusions: PCT H12-H36 did not miss any IBI whereas < H12 PCT could missed IBI diagnoses. PCT H12-H36 might be included in clinical decision rule to help physicians to stop early antibiotics in febrile neonates.