Infants with Down syndrome are at increased risk for hospitalisation due to respiratory syncytial virus (RSV), a new study shows.
Down syndrome and other conditions, including congenital heart disease (CHD), have recently been recognised as risk factors for the infection, but there are no US population-based studies, Dr Eric A. F. Simoes and colleagues report online December 16 in the Journal of Paediatrics.
"We found that the risk for RSV hospitalisation in children with Down syndrome under 2 years of age was comparable with rates in infants with chronic lung disease and CHD, " Dr Simoes, of The Children's Hospital Colorado, Aurora, told Reuters Health by email.
He added that the risk "extends into the second year of life, even in those without cardiac disease."
The researchers examined hospitalisation data from the Colorado Health and Hospital Association and birth data from the Colorado Department of Public Health and Environment covering 1995 through 2006.
Increased risk for Down babies
Overall, there were 85 RSV hospitalisations in 630 Down syndrome children. Of these, 50 had no apparent concurrent risk factors such as CHD or prematurity.
The rate for RSV lower respiratory tract infection hospitalisation was 67 per 1,000 child-years compared with 12 per 1,000 child-years in a cohort of matched controls without Down syndrome (odds ratio, 5.99).
Even in the absence of other underlying conditions, the Down group continued to be at increased hospitalisation risk with a rate of 42 per 1,000 child-years (OR, 3.5).
They also had significantly higher severity scores and higher rates of mechanical ventilation, especially in older children. Almost 10% required mechanical ventilation compared to less than 2% of controls (p<0.001).
Benefits from prophylactic intervention
The median hospital stay for the Down group aged less than one year was four days; in those aged one to two years it was five days. In the control group, the stays lasted three and two days, respectively.
Compared to controls, children with Down syndrome were febrile significantly more often, were more frequently reported to have consolidation, and were more likely to have a clinical response to bronchodilator therapy. They had a significantly higher use of bronchodilators during their hospital stay, but otherwise did not differ in clinical presentation or management.
The researchers suggest further study of the reasons for increased hospitalisation and the potential for prevention, as well as the role of putative immune deficiencies underlying the pathogenesis of RSV lower respiratory tract infection in these patients.
"Our study suggests that children with Down syndrome, even without CHD, under 2 years of age, may benefit from... prophylactic intervention during the RSV season," Dr Simoes said.
(David Douglas, Reuters Health, January 2012)