CARESS: The Canadian Registry of Palivizumab

BACKGROUND:Palivizumab is indicated for respiratory syncytial virus (RSV) prophylaxis in high-risk children. However, relatively little is known about the current use, compliance, and outcomes associated with this medication. METHODS:A prospective, observational, registry based on 27 sites, with monthly follow-up of infants at high risk for RSV who received at least 1 dose of palivizumab during the 2005–2009 RSV seasons. RESULTS:A total of 5286 children were enrolled (56.6% male; 71.7% white; average gestational age, 32.1 ± 5.5 weeks). Of them, 3741 patients (70.8%) were prophylaxed for prematurity only, 449 (8.5%) for bronchopulmonary dysplasia/chronic lung disease, 508 (9.6%) for congenital heart disease, and 588 (11.1%) for other reasons. Overall, 19,485 doses were given. On average, infants received 86.0% ± 28.4% of their expected number of injections; 71.2% of infants received their injections in the recommended time periods. Of the 5286 participants enrolled, 308 patients were hospitalized for respiratory tract illness (hospitalization rate, 5.8%). The RSV-hospitalization rate was calculated as 1.38%. Having siblings increased likelihood of hospitalization (66.9% vs. 55.7%, P < 0.005), and was significantly correlated with time to hospitalization in this cohort (P = 0.050). CONCLUSIONS:The overall RSV-hospitalization rate in our study was within the range found in previous reports (1.3%–5.3%), although it did not mimic the declining rates of the US Palivizumab Outcomes Registry. This could be due to increased testing for RSV when hospitalized and increasing rates of prophylaxis of infants with underlying medical disorders.