title: Respiratory syncytial virus disease in preterm infants in the U.S. born at 32-35 weeks gestation not receiving immunoprophylaxis.
abstract: BACKGROUND
  The Respiratory Syncytial Virus (RSV) Respiratory Events Among Preterm Infants Outcomes and Risk Tracking (REPORT) study evaluated RSV disease burden in U.S. preterm infants 32-35 weeks gestational age (wGA) not receiving RSV prophylaxis.
  
  
  METHODS
  Preterm infants <6 months of age as of November 1st were followed prospectively at 188 clinics from September to 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-polymerase chain reaction. 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 to 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 to 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 1st 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.
authors.affiliation: From the *MedImmune Medical & Scientific Affairs, Gaithersburg, MD; †Departments of Pediatrics and Medicine, Emory University School of Medicine, Atlanta, GA; ‡Department of Pediatrics, University of Colorado, School of Medicine, and Department of Pediatrics, Children's Hospital Colorado, Aurora, CO; §former employee of MedImmune, Gaithersburg, MD; ¶Department of Pediatrics, University of Illinois, Chicago, IL; and ||Current: AstraZeneca, U.S. Medical Affairs, Gaithersburg, MD.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ambrose
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Anderson
authors.forename: Eric A F
authors.initials: EA
authors.lastname: Simões
authors.forename: Xionghua
authors.initials: X
authors.lastname: Wu
authors.forename: Hanaa
authors.initials: H
authors.lastname: Elhefni
authors.forename: C Lucy
authors.initials: CL
authors.lastname: Park
authors.forename: Frangiscos
authors.initials: F
authors.lastname: Sifakis
authors.forename: Jessie R
authors.initials: JR
authors.lastname: Groothuis
mesh_terms: D005865:Gestational Age; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D009305:Nasopharynx / Q000821:virology; D011446:Prospective Studies; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D012307:Risk Factors; D014481:United States / Q000453:epidemiology