Impact of Viral Lower Respiratory Tract Infection (LRTI) in Early Childhood (0-2 Years) on Lung Growth and Development and Lifelong Trajectories of Pulmonary Health: A National Institutes of Health (NIH) Workshop Summary.

Viral lower respiratory tract infections (LRTI) are ubiquitous in early life. They are disproportionately severe in infants and toddlers (0-2 years), leading to more than 100,000 hospitalizations in the United States per year. The recent relative resilience to severe Coronavirus disease (COVID-19) observed in young children is surprising. These observations, taken together, underscore current knowledge gaps in the pathogenesis of viral lower respiratory tract diseases in young children and respiratory developmental immunology. Further, early-life respiratory viral infections could have a lasting impact on lung development with potential life-long pulmonary sequelae. Modern molecular methods, including high-resolution spatial and single-cell technologies, in concert with longitudinal observational studies beginning in the prenatal period and continuing into early childhood, promise to elucidate developmental pulmonary and immunophenotypes following early-life viral infections and their impact on trajectories of future respiratory health. In November 2019, under the auspices of a multi-disciplinary Workshop convened by the National Heart Lung Blood Institute and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, experts came together to highlight the challenges of respiratory viral infections, particularly in early childhood, and emphasize the knowledge gaps in immune, virological, developmental, and clinical factors that contribute to disease severity and long-term pulmonary morbidity from viral LRTI in children. We hope that the scientific community will view these challenges in clinical care on pulmonary health trajectories and disease burden not as a window of susceptibility but as a window of opportunity.