743. Severity and Costs of Respiratory Syncytial Virus and Bronchiolitis Hospitalization in Commercially Insured Preterm and Term Infants Before and After the 2014 American Academy of Pediatrics Guidance Change on Immunoprophylaxis

Background. In 2014, the American Academy of Pediatrics (AAP) stopped recommending respiratory syncytial virus (RSV) immunoprophylaxis in infants 29-34 weeks gestational age (wGA) without chronic lung disease (CLD) or congenital heart disease (CHD). This study examined the impact of this guidance change on the severity and costs of first year of life RSV hospitalizations (RSVH) and all-cause bronchiolitis hospitalizations (BH) among preterm (PT) vs. term infants in the 2014-2016 seasonal years relative to the 2011-2014 seasonal years. Methods. Infants aged 0.05), but there was an increased use of MV in the 2014-2016 season (RSVH: 6.9% vs. 4.2%, P = 0.009; BH: 6.3% vs. 3.7%, P = 0.003). Mean costs per hospitalization were greater for PT infants in 2014-2016 compared with 2011-2014 (RSVH: $29,382 vs. $16,572, P = 0.059; BH: $26,101 vs. $15,896, P = 0.047), whereas mean term hospitalization costs were similar (RSVH: $15,011 vs. $15,472, P = 0.705; BH: $14,555 vs. $14,603, P = 0.957). Conclusion. RSVH and BH severity and per-hospitalization costs (higher among PT infants relative to term infants) increased following the 2014 AAP immunoprophylaxis guidance change. The increases are likely explained by more frequent RSV hospitalizations among higher-risk 29-34 wGA infants in 2014-2016.