According to results from a surveillance study, respiratory syncytial virus (RSV) infection in young children is seen to affect in both inpatient and outpatient settings.

The surveillance study was reported in the February 5 issue of the New England Journal of Medicine. "The Centers for Disease Control and Prevention (CDC) initiated the New Vaccine Surveillance Network... a prospective, population-based inpatient and outpatient surveillance for acute respiratory infections among children under 5 years of age in 2000 in Nashville and Rochester, New York, and in 2003 in Cincinnati," the authors write. "The aim of our study was to determine the population-based burden of RSV infection among hospitalized children and outpatients in emergency departments and primary care settings."

The study took place in 3 US counties in 5067 children younger than 5 years of age. Hospitalized children were enrolled from 2000 through 2004, and outpatients in emergency departments and pediatric offices were enrolled from 2002 through 2004. RSV was diagnosed with culture and reverse-transcriptase polymerase chain reaction while the clinical data was sourced from parents and clinical data.

The researchers calculated population-based rates of hospitalization linked to RSV infection and determined approximate rates of RSV-associated outpatient visits based on these. They found that RSV infections occurred in 919 or 18 % of the children and 20 % of the hospitalizations from November through April were due to RSV as were 18% of emergency department visits, and 15% of office visits for acute respiratory infections.

Pre mature babies and younger children between two to seven months old were more affected by the RSV virus. In children who were less than 6 months the average annual hospitalization rates were 17 per 1000 as compared to children under 5 years whose rates were 3 per 1000. In the children younger than 5 years estimated rates of RSV-associated office visits were 3 times those in emergency departments.

"The primary role of [RSV] in causing infant hospitalizations is well recognized, but the total burden of RSV infection among young children remains poorly defined," write Caroline Breese Hall, MD, from the University of Rochester School of Medicine and Dentistry in New York, and colleagues.

The virus is usually seen in late fall and it reaches its peak in December but this year its later than normal. Invading the lining of the airways, the virus causes inflammation and increased production of mucus which makes it very difficult for the infant to breathe and can even cause sleep apnea. As there is no cure for RSV, the virus has to run its course.

Local Health Authority Dr. Todd Bell said, "If your child is having difficulty breathing they have a snotty nose, this time of year we all think of RSV and maybe they should be evaluated by their physician."

"RSV infection is associated with substantial morbidity in U. S. children in both inpatient and outpatient settings," the study authors write. "Most children with RSV infection were previously healthy, suggesting that control strategies targeting only high-risk children will have a limited effect on the total disease burden of RSV infection"