Annual Clinical and Economic Burden of Medically Attended Lower Respiratory Tract Illnesses Due to Respiratory Syncytial Virus Among US Infants Aged <12 Months.

We developed a model to project the expected annual clinical and economic burden of medically attended lower respiratory tract illnesses due to respiratory syncytial virus (RSV-LRTI) among United States (US) infants aged <12 months by combining information on population size, disease rates, mortality rates, and unit costs. Among the 3.7 million US infants aged <12 months each year, a total of 592 700 cases of RSV-LRTI (hospitalizations: 48 499; emergency department visits: 144 599; outpatient clinic visits: 399 602) were projected to occur, yielding total annual costs of $1.6 billion. The annual burden of RSV-LRTI among US infants is considerable, especially among those aged <3 months, who account for 43% of total costs.