Abstract
In a population-based birth cohort study of respiratory syncytial virus surveillance in the United States, 897/1,680 (53.4%) children were infected during infancy; 25 (2.8%) of those were hospitalized. Among symptomatic infants, 143/324 (44.1%) had lower respiratory tract infections. These data provide benchmarks to monitor effects of maternal vaccines and extended half-life monoclonal antibodies.