Background Respiratory viral infections (RVI) among children with Down syndrome (DS) is a common cause of hospital admissions. Due to the underlying co-morbidities, the severity and length of hospitalization is high in this population.

Objectives We estimated and described the burden of RVI admission among infants with Down syndrome within the first 2 year of life.

Methods This is a single-centre cohort study that includes all infants diagnosed with Down Syndrome in our centre. Data on laboratory-confirmed RVI were extracted from the microbiology database and linked to the hospital Down syndrome database. Clinical data and details of hospital admission from 2006–2017 were extracted.

Results There was a total of 34 RVI admissions from 29/227 children (12.8%) in this cohort during the study period. Seven children (24.1%) had more than 1 RVI. Respiratory Syncytial Virus (RSV) was the main causative pathogen, accounting for 61.8% of all admissions (21/34). Parainfluenza virus (6/34,17.6%) and Metapneumovirus (5/34, 14.7%) infection were the other common infections. Five infants (14.7%) required admission to the high dependency unit/intensive care unit, all with RSV infection. Thirteen infants (38.2%) required respiratory support during their admission, ranging from nasal cannula to continuous positive airway pressure (CPAP). The median length of hospitalization was 6 days (range 2–41 days) and the median length of stay in the high dependency/intensive care unit was 8 days (range 3–18 days). A total of 29/34 (85%) who had co-morbidities, of which 6 had more than 1 morbidity.

Conclusions Up to 13% of children with Down Syndrome required admission due to RVI in our cohort. RSV infections was the predominant causative infection, accounting for up to 62% of all admission and all admission to high-dependency/intensive care unit.