Early-life respiratory infections and their association with chronic lung disease: an expert perspective.

INTRODUCTION: Early-life respiratory infections may disrupt lung development during critical fetal, neonatal, and infant windows, when alveolarization, airway and vascular maturation, and immune programming remain active, potentially causing effects beyond the acute illness. AREAS COVERED: This narrative review examines prenatal and postnatal respiratory infections and long-term respiratory outcomes, with emphasis on chorioamnionitis, fetal inflammatory responses, bronchopulmonary dysplasia, respiratory syncytial virus, and other pathogens. Literature was identified through targeted searches of biomedical databases and reference lists using terms related to early-life infection, lung development, bronchopulmonary dysplasia, wheeze, asthma, lung function, COPD, and respiratory mortality. Priority was given to systematic reviews, meta-analyses, longitudinal cohorts, mechanistic studies, and relevant reports. Proposed pathways include impaired alveolar and vascular growth, epithelial injury, immune dysregulation, trained immunity, airway remodeling, and reduced peak lung function. Epidemiological evidence linking early lower respiratory tract infection with recurrent wheeze, asthma, impaired lung function, COPD-like trajectories, and respiratory mortality is appraised. EXPERT OPINION: Early respiratory infections likely contribute to chronic morbidity through interactions among pathogen, timing, host susceptibility, prematurity, and environmental exposures. Causality remains difficult to establish. Newly available respiratory syncytial virus prevention strategies may clarify whether preventing severe infection improves long-term lung health. Standardized outcomes and longitudinal follow-up are essential.