Effect of palivizumab prophylaxis on subsequent recurrent wheezing in preterm infants.

BACKGROUND AND OBJECTIVES Palivizumab effectively prevents severe respiratory syncytial virus (RSV) disease in preterm infants. Our objective was to test whether palivizumab prophylaxis given to preterm infants during the first RSV season reduces the incidence of subsequent recurrent wheezing up to 3 years of life. METHODS We conducted an observational prospective multicenter (52 registered hospitals in Japan) case-control study in preterm infants with a gestational age between 33 and 35 weeks followed for 3 years. During the 2007-2008 RSV season, the decision to administer palivizumab was made based on standard medical practice. In April 2008, 52 hospitals were recruited. Study participants were prospectively followed to the age of 3 years. Parents of study subjects reported the infants' physician's assessment of recurrent wheezing, used a report card and a novel mobile phone-based reporting system by using the Internet. The primary end point was the incidence of physician-diagnosed recurrent wheezing. RESULTS Of 444 preterm infants enrolled, 349 received palivizumab during the first 6 months of life and 95 infants did not. Physician-diagnosed recurrent wheezing was observed in 6.4% and 18.9% of infants in the treated and untreated groups, respectively (P < .001). This difference remained significant after adjustment for known risk factors of recurrent wheezing (P < .001). CONCLUSIONS Palivizumab prophylaxis administered to preterm infants 33 to 35 weeks' gestational age is associated with a significantly lower incidence of recurrent wheezing during the first 3 years of life.