Comparison of First- and Second-Season Palivizumab Prophylaxis in Patients with Chronic Lung Disease (CLD) in the ‘Caress’ Database (2005-2014)

Abstract

Abstract BACKGROUND: Respiratory syncytial virus (RSV) related hospitaliza-tion (RSVH) rates are 10-fold higher in infants with CLD compared with healthy term infants until 24 months of age. Current pediatric advisory guidelines recommend RSV prophylaxis for CLD infants < 2 years of age based on oxygen requirement for at least 28 days after birth during the first RSV season and those who continue to require chronic medical therapy for the management of CLD during the second season. OBJECTIVES: This study compared RSVH rates in CLD infants who received palivizumab during the first RSV season (FS) versus the second season (SS) in the Canadian Registry of Palivizumab (CARESS) database. DESIGN/METHODS: CARESS is a prospective registry of infants who received 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 were recorded monthly. Infants aged < 24 months with CLD were enrolled. RESULTS: 797 (55%) and 647 (45%) of 1444 CLD infants were prophy-laxed during FS and SS respectively (average age: 6.9 [FS] versus 13.6 [SS] months). SS infants had a lower gestational age [29.7 versus 31.3 weeks, F(1, 1440) = 29.9, p=<0.0005] and birth weight [1447 versus 1762 grams, F(1, 1436) = 29.3, p=<0.0005]. Infants prophylaxed in the SS also experienced more complicated neonatal courses with: prolonged respiratory support [63.4 versus 50.0 days, F(1, 1089) = 16.9, p=<0.0005], oxygen therapy [135.7 versus 74.8 days, F(1, 1155) = 97.4, p=<0.0005], and longer hospital stays [102.0 versus 72.0 days, F(1, 1369) = 62.1, p=<0.0005]. RSVH rates were 2.23% (FS) and 2.66% (SS). Cox regression adjusted for daycare attendance, multiple births, gestational age, birth weight and neonatal complications found no significant differences in the time to first RSVH between FS and SS infants (Hazard ratio: 0.96, 95% CI 0.37–2.52, p=0.94). CONCLUSION: SS infants who received RSV prophylaxis for CLD had a similar hazard of RSVH to those who only received palivizumab in the first year of life. The findings imply that FS and SS infants are correctly selected for RSV prophylaxis based on the stipulated criteria and their severity of illness and that SS infants are equally at risk for RSVH compared to FS infants.