40: Respiratory Illness and Respiratory Syncytial Virus Hospitalizations in the Canadian Registry for Synagis (CARESS) Over Eight Seasons (2005–2013)

Abstract

Background: Global, pediatric advisory committee guidelines recommend palivizumab prophylaxis for -infants at high risk for respiratory syncytial virus (RSV) infection and hospitalization. CARESS is a prospective registry that documents utilization, compliance and health outcomes of all Canadian infants who received >1 dose of palivizumab for RSV prophylaxis across 32 sites during the 20052013 RSV seasons. Objectives: Compare respiratory illness hospitalizations (RIH), RSVpositive hospitalizations (RSVH) and serious adverse events (SAE) among infants who received palivizumab for various indications. Design/Methods: Demographic data were collected at enrollment and respiratory illness-related hospitalization events were recorded monthly. Standard risk indications that qualified for RSV prophylaxis were categorized as prematurity (<35 completed weeks gestational age), chronic lung disease (CLD) and hemodynamically significant congenital heart disease (CHD). Infants with other underlying medical illnesses such as cystic fibrosis, neuromuscular impairments, Down syndrome and immune-compromise (MI) also received prophylaxis. SAEs were recorded during each RSV season. Cox proportional hazards analyses were conducted to examine hospitalization rate differences across indications adjusting for group differences. Results: Of the 16,290 infants enrolled, 10,576 were premature, 1290 had CLD, 1758 had CHD, and 2666 qualified with MIs. Of 211 SAE reports (excluding RIH related events), only nine were possibly related to palivizumab. After adjusting for risk factors (living with siblings, residing with >1 smoker in the household, family history of atopy, and multiple birth status), the hazard (hazard ratio [95% CI]; P value) for RIH was significantly higher in infants with CLD (2.49 [95% CI 2.05 to 3.01]; P<0.0005), CHD (2.20 [95% CI 1.84 to 2.64]; P<0.0005), and MI (2.02 [95% CI 1.71 to 2.38]; P<0.0005) compared to those with prematurity only. CHD infants, unlike CLD and MI, had a significantly higher hazard ratio for RSVH compared to the premature group (1.63 [95% CI 1.09 to 2.439]; P=0.018). Conclusions: Hazard for RIH was dissimilar across indications for prophylaxis, with CLD, CHD, and MI at greater risk for RIH than prematurity. However, only CHD infants had an increased hazard for RSVH. Palivizumab was well-tolerated across groups without any directly related SAEs.