With an attack rate approaching 100% among susceptible individuals, HRSV is a major respiratory pathogen among young children (particularly those 2-3 months of age) and the foremost cause of lower respiratory disease among infants.

• HRSV accounts for 20-25% of hospital admissions of young children for pneumonia and for up to 75% of cases of bronchiolitis in this age group.
• The virus is transmitted efficiently via contact with contaminated fingers or fomites and by spread of coarse aerosols. The incubation period is ~4-6 days.