At lot is known about acquisition of respiratory syncytial virus (RSV) in pediatric wards inside the hospital. However, only few data are available on the incidence of RSV infections in neonatal intensive care units (NICUs). The aim of the present study was to test the hypothesis that a considerable number of preterm infants acquires RSV already at the NICU, prior to the first discharge home. In order to test this hypotheses, a prospective epidemiologic survey (twice weekly analysis of nasopharyngeal swabs for RSV by seminested RT-PCR for a period of 8 weeks) was performed in all preterm...