Respiratory syncytial virus disease in preterm infants in the U.S. born at 32-35 weeks gestation not receiving immunoprophylaxis

Pediatr Infect Dis J. 2014 Jun;33(6):576-82. doi: 10.1097/INF.0000000000000219.


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.

Trial registration: NCT00983606.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gestational Age
  • Hospitalization
  • Humans
  • Infant
  • Infant, Newborn
  • Infant, Premature
  • Nasopharynx / virology
  • Prospective Studies
  • Respiratory Syncytial Virus Infections / epidemiology*
  • Respiratory Syncytial Virus Infections / prevention & control
  • Respiratory Syncytial Virus Infections / virology
  • Risk Factors
  • United States / epidemiology

Associated data