Burden of Respiratory Syncytial Virus Infection during the First Year of Life

Abstract

Background: Although many infants with respiratory syncytial virus (RSV) infection are hospitalized, most infants are treated as outpatients. Limited data are available on the burden of RSV in outpatient infants. Methods: In a prospective study, we enrolled 431 newborn infants and followed them up for a 10-month period (September-June). During each respiratory illness, we examined the infants and obtained nasopharyngeal specimens for the detection of RSV. The parents completed daily symptom diaries throughout the study. Results: Among 408 active participants, the seasonal incidence rate of RSV illness was 328.4 per 1000 (95% confidence interval [CI], 275.2-389.0). Infants with ≥1 sibling had a 1.9-fold higher incidence of RSV illness than those without siblings (95% CI, 1.3-2.8; P