Comparing First- and Second-Season Palivizumab Prophylaxis in Patients with Hemodynamically Significant Congenital Heart Disease (HSCHD) in the ‘Caress’ Database (2005-2014)

Abstract

Abstract BACKGROUND: Compared with normal children, RSV-related hospi-talization (RSVH) rates in children with HSCHD are 2-4 fold higher even up to 2 years of age with an overall weighted mean mortality rate of 5.2%. Pediatric advisory guidelines recommend prophylaxis against respiratory syncytial virus (RSV) for infants with HSCHD. However, current recommendations cast doubt as to whether prophylaxis is beneficial beyond 1 year of age. OBJECTIVES: To determine whether there are differences in RSVH in HSCHD infants receiving palivizumab during the first versus second RSV season in the Canadian Registry of palivizumab (CARESS). DESIGN/METHODS: CARESS is a prospective registry of infants who received ≥1 dose of palivizumab at one of 32 sites across Canada during the 2005-2014 RSV seasons. Demographic data were collected at enrollment and respiratory-illness-related hospitalization events recorded monthly. In the event of a hospitalization, the relevant hospital records were reviewed by the site’s research nurse for detailed information on criteria for hospital-ization, length of stay (regular ward vs. ICU), days on respiratory support and/or intubation, and RSV test type and diagnosis. Infants aged <24 months with cyanotic or acyanotic HSCHD were recruited. RESULTS: 1306 (64.9%) of 2013 infants received prophylaxis only for the first season. 707 (35.1%) were prophylaxed during the second season (average age in months: 4.7 [first season] vs 14.7 [second season]). Baseline demographics for both seasons were similar. However, infants aged >1year had a more complicated neonatal course, with significantly longer neonatal length of stay (46.7 versus 25.6 days). Infants received: 4.5±1.4 injections; 90.5% of their expected injections and 88.2% of their injections within the appropriate time intervals. 26 infants in the first year (RSVH rate: 2.26%) and 11 infants in the second year (RSVH rate: 2.09%) were hospitalized. Cox regression analysis showed no significant differences in hazards between infants in their first or second year of prophylaxis in the time to first RSVH (Hazard ratio: 1.4, 95%CI 0.5-4.0, p=0.52) CONCLUSION: Infants enrolled in the CARESS database in the second RSV season had a similar hazard of RSVH as those in the first year of life. These findings suggest that infants aged >1 year with HSCHD who remain unstable, are equally at risk for RSVH and merit palivizumab prophylaxis.