Outpatient RSV lower respiratory infections among high-risk infants and other pediatric populations.

Objective: To identify the frequency of outpatient, non-hospitalized visits for respiratory syncytial virus (RSV) lower respiratory tract infection (LRI) among children and high-risk infants.
Study Design: Published studies that reported population-based rates of outpatient RSV illness were reviewed. In addition, we conducted a retrospective cohort study from a national claims database including preterm and full term infants born between April 2004 and April 2006 <6 months of age and continuously enrolled through their first RSV season.
Results: In the selected published studies, rates of outpatient RSV LRI were highest among infants and young children (ranging from 6.9 to 11 per 1,000 children age 1-4 years to 157.5 to 252.0 per 1,000 children age <1 year). In the cohort study, rates of outpatient RSV LRI among preterm infants <or=32 wGA or with chronic lung disease (CLD) ranged from 158.7 to 272.6 visits per 1,000 children. Rates for late preterm (33-36 wGA) infants ranged from 183.3 to 245.7 per 1,000, which was higher than full term infants (128.8 to 171.3 per 1,000).
Conclusions: Approximately 1 in every 5 of high-risk infants will be affected during their first RSV season, which indicates a fairly high and unrecognized reservoir of disease. Outpatient RSV LRI visits increase with younger age and prematurity.