RSV Hospitalization in Down Syndrome in the Canadian Registry of Synagis (CARESS) Following Prophylaxis (2006–2011)

Abstract

Background: The Canadian Registry of Synagis (CARESS) tracks palivizumab use and RSV hospitalizations iincluding 299 full term Down syndrome (DS) infants without congenital heart disease. Objective(s): To determine respiratory illness (RIH) and RSV hospitalization (RSVH) rates in healthy DS)infants who received palivizumab compared to: 1) infants with underlying medical disorders (MD) and 2) infants who meet standard indications for RSV prophylaxis (SD). Design/Methods: A prospective, observational, registry of infants who received 1 dose of palivizumab during the 2006-2011 RSV seasons. Data collected monthly. Result(s): 10,061 infants were enrolled (DS: 299, 3.0%; infants with MD: 1247, 12.4%; and SD: 8515, 84.6%). Participants were significantly different (p<0.005) in most demographic variables and risk factors such as siblings, smoke exposure, >= 5 household members and daycare attendance. Compliance rates relative interdose intervals (p=0.323) across the groups was similar, though the DS group received a significantly higher proportion of their expected injections (p=0.018). A significantly greater proportion of DS had RIHs compared to MD (p=0.025), but not SD infants. DS infants did not have a significantly different RSVH rate (1.18%) from either MD (2.55%; p=0.627) or SD (1.52%; p=0.547). Conclusion(s): Rates of hospitalization for respiratory illnesses and RSV-related hospitalization did not differ among the groups following prophylaxis. Palivizumab may be efficacious in reducing RSVH in DS compared to reported historical untreated controls in a similar Danish cohort of DS patients (untreated; 7.6%; versus treated; 1.6% - 77% reduction).