RSV loads of infants are already declining near the time of hospitalization. For optimal effect, antiviral and other RSV therapeutics therefore may need to be applied before this occurs. 134 RSV-hospitalized infants were studied to determine the timing of events and their healthcare seeking behavior prior to hospitalization. Sixty-two percent of infants had contact with a health care professional greater than or equal to1 day prior to hospitalization and 46% had such a contact on greater than or equal to2 different days prior to hospitalization. The mean (S.D.) duration of RSV symptoms prior to hospitalization was 3.9 +/- 2.3 days and prior to first health care contact was 2.6 +/- 1.8 days. RSV-hospitalized infants routinely have contact with health care professionals at significantly early time points in their illness. These contacts are potential opportunities for initiation of early anti-RSV therapy. (C) 2004 Elsevier B.V. All rights reserved.