Epidemiologic differences of four major respiratory viruses between children, adolescents, and adults in Korea

The purpose of this study was to investigate the epidemiology of four major respiratory viruses among the Korean population. This retrospective study was conducted over four years, from January 2005 to December 2008. Among a total of 23,806 specimens, 5512 virus isolates underwent culture for influenza A and B viruses (IFA/B), parainfluenza virus (PIV), respiratory syncytial virus (RSV), and adenovirus (ADV). Patients were divided into two groups: children/adolescents and adults. The viruses detected in specimens from children/adolescents included PIV (7.8%), RSV (7.3%), ADV (4.0%), IFA (2.9%), and IFB (2.2%). In adults, IFB (5.6%), IFA (4.4%), RSV (1.1%), PIV (0.5%), and ADV (0.2%) were detected, thus demonstrating two distinct patterns of virus infection. Influenza viruses had similar seasonal patterns and periods of infection among children/adolescents and adults; however, the isolation rate in adults was slightly higher than that in children and adolescents. Correlation coefficient analysis based on weekly seasonal patterns indicated that influenza viruses were detected a week earlier in children than in adults. RSV, PIV, and ADV did not show similar trends between the two age groups due to low detection rates and sporadic isolations among adult patients. Of note, different respiratory viruses should be considered depending on patient age when a clinical respiratory viral infection is suspected. Furthermore, in the case of influenza, a preceding epidemic among a pediatric population could be useful to predict a subsequent epidemic among adults.