RSV-associated hospitalizations in Alaska Native infants.

Purpose: Retrospective reviews for 1986-1992 suggested that Alaska Native children experience high rates of respiratory syncytial virus (RSV)-associated hospitalization; however, the epidemiology of RSV infections has been poorly characterized.
Methods: A prospective hospital-based surveillance study was undertaken to determine rates of RSV-associated hospitalization in Alaska Native children < 36 months from the Yukon-Kuskokwim Delta.
Results: During the first study year, October 1993 to September 1994, there were 40 RSV cases (hospitalization rate, 53/1,000 infants < 1 year of age); however, during the second year, October 1994 to September 1995, there were 251 RSV cases (hospitalization rate, 294/1,000 infants). An unusually high proportion, 12%, of RSV cases were < 1 month of age. Disease severity was higher for children with a history of prematurity, heart, or lung disease (p = .001, X2 analysis). Of 255 cell cultures during 1994-1995, 190 were RSV-positive, 11 were positive for influenza, 4 for adenovirus, and 1 for parainfluenza. This study demonstrates wide seasonal variation in a population with an extremely high RSV hospitalization rate; increased disease severity associated with young age and pre-existing medical conditions; and co-circulation of RSV with other viruses.