The Pediatric Investigators Collaborative Network on Infections in Canada study of predictors of hospitalization for respiratory syncytial virus infection for infants born at 33 through 35 completed weeks of gestation.

Background: Infants born at 33 through 35 completed weeks of gestation (33-35GA) are at risk for severe respiratory syncytial virus (RSV) infection, and palivizumab prophylaxis lowers hospitalizations for RSV infection by as much as 80%. The 33-35GA cohort comprises 3-5% of annual births; thus expert panels recommend limiting prophylaxis to situations in which frequency or health care impact of RSV infection is high. This study sought to identify independent risk factors for hospitalization for RSV infection. Methods: This was a multicenter, prospective, observational cohort study of 33-35GA infants followed through their first RSV season (2001/2002 or 2002/2003).