National cohort study showed that infants with Down's syndrome faced a high risk of hospitalisation for the respiratory syncytial virus.

Abstract

The respiratory syncytial virus (RSV) is a leading cause of hospitalisation in infants. We investigated this risk in children with Down's syndrome under two years of age, adjusted for other known risk factors. This national, retrospective 1:2 matched cohort study comprised all Swedish children born with Down's from 2006 to 2011, who were each randomly matched to two controls without Down's. Data on RSV hospitalisation and risk factors for RSV were obtained from national registers. The risk of RSV hospitalisation was assessed using multivariable Cox regression with pairwise stratification. The study comprised 814 children with Down's and 1628 controls. We found that 82 children with Down's (10.1%) and 22 controls (1.4%) were hospitalised for RSV. The hazard ratio for children with Down's was 4.00 (95% confidence interval 1.58-10.13) for up to one year of age and 6.60 (95% CI: 2.83-15.38) for up to two years of age, adjusted for other risk factors. During the second year of life, RSV hospitalisation continued for children with Down's, while it was minimal for the controls. Children with Down's faced a high risk of RSV hospitalisation, which continued beyond the first year of age.