UCL Great Ormond Street researchers built a laboratory model of infant lungs using pediatric airway cells, blood vessel cells, and neutrophils to study why RSV is more severe in babies than in adults. Published in Nature Communications, the work identified neutrophil myeloperoxidase as a functional biomarker for RSV severity and suggested the neutrophil-epithelial interaction as a therapeutic intervention point. The model is designed to support more human-relevant in vitro therapeutic screening, with an emphasis on targeting both viral activity and the inflammatory immune response that drives airway damage.