263 RSV Hospitalization in Cystic Fibrosis in the Canadian Registry of Synagis(R) (Caress) following Prophylaxis (2005-2011)

Abstract

Background and Aims The Canadian Registry of Synagis (CARESS) tracks palivizumab utilization and respiratory syncytial virus (RSV) hospitalizations in high-risk infants including 186 with cystic fibrosis (CF). This study compares respiratory illness (RI) and RSV positive hospitalization (RSVH) rates in CF infants versus: 1. those with other underlying medical disorders (MD) and 2. those who meet standard indications for RSV prophylaxis (SD). Methods A prospective, observational registry of infants from 30 sites who received >=1 dose of palivizumab during the 2005-2011 RSV seasons. Palivizumab utilization and RI outcomes were collected monthly over each individual season. Results 10,452 infants were enrolled (CF: 186, 1.8%; MD: 1378, 13.2%; SD: 8888, 85.0%). There were significant differences (p<0.05) between the three groups in gestational and enrolment ages, weight at birth and at enrolment and proportions of: Caucasians, siblings, multiple births, daycare attendance, smokers in the household, >5 people in the household, immediate family history of atopy, and complexity of neonatal course. Infants with CF had a lower RI hospitalization rate than the MD (4.3% versus 11.0%, p=0.003) but not the SD group (5.8%, p=0.522). For RSVH rate, CF infants were not significantly different from the MD (0.72% versus 2.46%, p=0.227) or SD (1.49%, p=0.999) groups. In the Cox proportional analysis, hazard ratios of time to first RSVH in CF were similar to MD (p=0.272) and SD infants (p=0.422). Conclusions This is the largest report of CF infants who have received palivizumab world-wide. Despite RI rate differences, RSVH rates appear similar to those in MD and SD.