Pertussis vaccination and the risk of respiratory syncytial virus-associated hospitalization.

Background: Animal data suggest an association between recent vaccination with a pertussis-containing vaccine and increased severity of respiratory syncytial virus (RSV) infection. We sought to determine whether such an association exists in humans by studying a population-based cohort of young children.

Patients And Methods: We performed a nested case-control study of 280 children younger than 24 months of age hospitalized with RSV infection in Olmsted County, MN from January 1990 to December 1999.