Infants younger than 2 months are at the greatest risk of being hospitalized for respiratory syncytial virus (RSV), according to the results of a study published online on July 22, 2013, in Pediatrics. To clarify conflicting estimates of RSV hospitalization rates found in previous studies, the researchers analyzed data from a prospective, population-based study of children younger than 2 years hospitalized for acute respiratory illness from October through March between 2000 and 2005.
A total of 2149 children were enrolled in the study and 26% were infected with RSV. The average hospitalization rate for RSV in all children younger than 2 years was 5.2 per 1000. Infants at 1 month of age had a rate of hospitalization for RSV of 25.9 per 1000, the highest found in the study. Infants 2 months and younger had an RSV hospitalization rate of 17.9 per 1000 and made up 44% of all children hospitalized with RSV. The RSV hospitalization rate for children in this age group was approximately twice that of children aged 3 to 5 months and more than 4 times that of those aged 6 to 11 months. In addition, the RSV hospitalization rate for very preterm infants was 3 times that of term infants.