Risk factors for severe respiratory syncytial virus infection among Alaska native children.

OBJECTIVE: The incidence of hospitalization for respiratory syncytial virus (RSV) infection among Alaska Native children is much higher than among non-Native populations in the United States. We conducted this study to better understand factors associated with hospitalization attributable to RSV infection in this high-risk population. DESIGN: Case-control study, including collection of cord blood for RSV-neutralizing antibody measurement. SETTING: Remote region of southwest Alaska served by 1 regional hospital and 2 referral hospitals. SUBJECTS: Case-patients identified through surveillance for RSV infection and matched control subjects without acute respiratory infection hospitalization. RESULTS: Breastfeeding was associated with a lower risk of RSV hospitalization (odds ratio: 0.34), whereas underlying medical conditions (primarily prematurity) were associated with increased risk (odds ratio: 6.25). Environmental factors associated with a higher risk of hospitalization included household crowding (4 or more children in the household and crowding index > or =2). The level of maternal RSV-neutralizing antibody was not associated with the risk of hospitalization. CONCLUSIONS: In this region with extremely high risk of RSV hospitalization, several measures, such as encouraging breastfeeding and reducing household crowding, could reduce the risk of hospitalization attributable to RSV.