 This was a Phase 12, randomized, double-blind study in which motavizumab MEDI-524 or palivizumab was administered to children who previously participated in MI-CP104. Children who received at least 3 doses of motavizumab in MI-CP104 were eligible for enrollment. Subjects were randomized 1:1 to receive motavizumab or palivizumab at 15 mgkg by IM injection every 30 days for a total of 4-5 injections during the 2004-05 RSV season subsequent to the season in which they were participants of MI-CP104. All subjects were evaluated prior to and 30 minutes after each injection of study drug with 2 follow-up evaluations, one at 30 days and the other at 90-120 days after the last dose. 