Synagis is used in the following groups of children, who are at high risk for this disease: • children who are less than 6 months old and were born prematurely at 35 weeks gestation or less (five or more weeks too early), • children who are less than 2 years of age and have had treatment for bronchopulmonary dysplasia (abnormal lung tissue, usually found babies who were born prematurely) within the last 6 months, • children who are less than 2 years of age and were born with a serious heart disease.