Background: The Respiratory Syncytial Virus (RSV) Respiratory Events Among Preterm Infants Outcomes and Risk Tracking (REPORT) study evaluated RSV disease burden in US preterm infants 32-35 weeks gestational age (wGA) not receiving RSV prophylaxis.
Methods: Preterm infants <6 months of age as of November 1 were followed prospectively at 188 clinics from September-May 2009-2010 or 2010-2011. Nasal and pharyngeal swabs were collected for medically-attended acute respiratory illnesses (MAARI) and tested for RSV by qRT-PCR. Risk factors were assessed using multivariate Cox proportional hazard model adjusted for seasonality.
Results: Of 1642 evaluable infants, 287 experienced RSV MAARI. Rates of RSV-related MAARI, outpatient lower respiratory tract illness, emergency department visits, and hospitalization (RSVH) during November-March were 25.4, 13.7, 5.9, and 4.9 per 100 infant-seasons, respectively. Preschool-aged nonmultiple birth siblings and daycare attendance were consistently associated with increased risk of RSV. RSVH rates were highest in infants 32-34 and 35 wGA who were <6 months of age during November-March with daycare attendance or nonmultiple-birth preschool-aged siblings (8.9 and 9.3 per 100 infant-seasons, respectively, versus 3.5 for all other infants, P<0.001). Chronologic age <3 months was associated with a higher RSVH rate for infants 35 wGA but not for infants 32-34 wGA.
Conclusions: In US preterm infants who were 32-35 wGA, <6 months on November 1, and not receiving RSV prophylaxis, the burden of RSV MAARI was 25 per 100 infant-seasons. The highest RSVH rates occurred among those with daycare attendance or nonmultiple birth preschool-aged siblings while they were <6 months of age during the RSV season.
ClinicalTrials.gov Identifier: NCT00983606.
(C) 2014 by Lippincott Williams & Wilkins, Inc.