Study to Assess the Immune Reactivity of the Liquid and Lyophilized Formulations of Palivizumab (MEDI-493, Synagis)

Exclusion Criteria

• •Hospitalization at the time of randomization (unless discharge is anticipated within 3 weeks)
• •Be receiving mechanical ventilation at the time of study entry (including CPAP)
• •Congenital heart disease (children with uncomplicated CHD \[e.g., PDA, small septal defect\] and children with complicated CHD who are currently anatomically and hemodynamically normal can be enrolled).
• •Mother with HIV infection (unless the child has been proven to be not infected)
• •Life expectancy \<6 months
• •Known allergy to Ig products
• •Acute respiratory or other acute infection or illness
• •Previous reaction to IGIV, blood products, or other foreign proteins
• •Receipt of lyophilized palivizumab, RSV-IG IV, or other RSV-specific monoclonal antibody, or any other polyclonal antibody (for example, Hepatitis B IG, IVIG, VZIG) within 3 months prior to randomization
• •Any previous receipt of MEDI-524
• •Participation in other investigational drug product studies