Background: In 2014, the American Academy of Pediatrics (AAP) revised the recommendations for respiratory syncytial virus (RSV) immunoprophylaxis. Palivizumab was no longer recommended for children with hemodynamically significant congenital heart disease (hs-CHD) in the second year of life (12-24 months) at the start of the RSV season. Herein, we describe a historical, observational cohort study that was conducted to investigate the impact of the 2014 AAP revised guidance on the contemporary burden of RSV hospitalizations (RSVH) and bronchiolitis hospitalizations (BH) in this population.

Methods: Using encounter data from 51 US children’s hospitals that comprise the Pediatric Health Information System (PHIS), we studied children with higher-risk CHD aged ≤24 months at the start of the RSV season (assumed November 1) and hospitalized for RSV infection or bronchiolitis from 2010 to 2017 (November-March). Chi-squared tests were used to compare groups before and after the 2014 policy using a p-value to examine statistical significance. Poisson regression models and SAS macro %NLEstimate were used to test the difference in difference of rates in hospitalizations to quantitatively describe changes in hospitalization rates pre- and post-2014.

Results: The overall cohort of children aged ≤24 months at RSV season start included 104,687 RSVH and 164,055 BH; among RSVH, 3.6% (n=3790) were identified as higher-risk CHD. The RSVH proportion for all children with higher-risk CHD aged ≤24 months increased by 17.5% after the 2014 guidance change (3364 per 100,000 before and 3954 per 100,000 after; P<0.0001). Stratified analyses by chronologic age demonstrated increases for children with higher-risk CHD aged ≤11 months (2818 per 100,000 before and 3180 per 100,000 after; P=0.001; 12.8% increase) as well as those aged 12 to 24 months (545 per 100,000 before and 774 per 100,000 after; P<0.0001; 42.0% increase). The percentage increase was significantly greater in the 12-24 months group than in ≤11 months group (42% vs 12.8%; P=0.0126). Higher-risk CHD children aged 12-24 months with RSVH also had increased intensive care unit admission rates after 2014 (191 per 100,000 before and 339 per 100,000 after; P<0.0001). A similar pattern of results was observed for BH.

Conclusions: This analysis highlights the increase in RSVH, BH, and associated disease severity among children with higher-risk CHD within PHIS after the AAP revised its policy recommendations for palivizumab immunoprophylaxis in this group in 2014