Incidence and seasonality of respiratory syncytial virus hospitalisations in young children in Denmark, 2010 to 2015

Abstract

For future decisions on respiratory syncytial virus (RSV)-vaccination strategies and implementation into national immunisation-programmes, we used national registry data (hospitalisation, microbiology and vital statistics) to determine the age-specific incidence and direct medical costs of annual RSV-associated admissions in children < 5 years-old for the period of 2010-2015. We identified ca 2,500 RSV-associated hospitalisations annually amounting to total direct medical-costs of ca EUR 4.1 million per year. The incidence of RSV-associated hospitalisations peaked in infants 1-2 months of age followed by infants 2-3 months of age, and infants < 1 month of age, respectively. Infant boys were at higher risk of severe RSV infection as compared to infant girls: male-to-female ratio peaked with 1.4 at four months of age and gradually levelled out with increasing age to 1.0 at 4 years of age. Five RSV-associated deaths were identified. Our findings demonstrate that in a western country as Denmark, RSV constitutes a considerable burden on childhood health. Furthermore, the best approach to reduce the high incidence of RSV-associated hospitalisations in young infants < 3 months of age may be maternal vaccination due to general challenges in achieving sufficient and protective immune responses in young infants.

Keywords: RSV; Respiratory syncytial virus; cost-benefit; disease burden; incidence.

Figure 1

Monthly respiratory syncytial virus-hospitalisation incidence per 1,000 children up to 12 months of age, in Denmark, during the study period, 1 January 2010–26 June 2015

Figure 2

Duration in days of respiratory syncytial virus-associated hospitalisations among children < 5 years of age by age groups, in Denmark, during the study period, 1 January 2010–26 June 2015