Objective To determine current usage of palivizumab prophylaxis, compliance patterns, hospitalization rate (HR) and outcomes in children at high-risk of respiratory syncytial virus (RSV) infection through a Canadian Registry Database (CARESS).

Methods A prospective, observational, study of Canadian infants who received palivizumab in the 2006/2007 RSV season. Neonatal and demographic data were collected upon enrolment. Parents/caregivers were contacted monthly for data on palivizumab utilization, compliance and outcomes related to any respiratory tract events.

Results 1224 infants, aged 2 days–34 months (mean = 5.17 months) who received at least one injection of palivizumab were recruited from 16 regional sites across Canada. Participants were typically male (57.4%) and Caucasian (72.2%). Gestational age was 31.5±4.3 weeks. 914 infants (74.7%) received palivizumab primarily for prematurity (⩽35 completed weeks gestational age). 119 (9.7%) had bronchopulmonary dysplasia (BPD) and required supportive oxygen therapy.119 (9.7%) had congenital heart disease and 72 (5.9%) were prophylaxed for other risk factors. 76.9% of subjects received at least 4 injections of palivizumab. The majority of injections were administered within recommended monthly time intervals (73.5%). There was a 5.1% HR for respiratory tract events (e.g., bronchiolitis or pneumonia). The RSV positive HR was 1.4% (proven RSV). Hospitalization rates for respiratory tract events were highest in those with BPD (12.8%, p<0.001), and those of Hispanic (15.4%) or Aboriginal descent (13.6%)(p = 0.051).

Conclusions Compliance with the course of palivizumab was very good. The RSV hospitalization rate observed in the 2006/2007 CARESS season was lower than that previously documented in the scientific literature.