Inclusion and exclusion criteria for entry into study
| Inclusion criteria | Exclusion criteria |
| Age less than 12 months of age | Previous hospital admissions with respiratory tract illnesses |
| Confirmed RSV infection | Chronic respiratory illness |
| Informed parental consent | Congenital heart disease |
| Randomisation within 12 hours of admission | Prematurity |
| Pre-existing immunodeficiencies | |
| Recent exposure to varicella or tuberculosis | |
| Prolonged exposure to systemic steroids |
RSV, respiratory syncytial virus.