Shifting Age Distribution of Dengue Infection: Analysis of Data Collected in Kamphaeng Phet Province, Thailand from 1994 to 2010

Recent studies suggest the average age of dengue infection is increasing and may be due in part to a shift in dengue environmental and age distribution. Building upon initial reports, this study assessed the average age of symptomatic dengue infection in Kamphaeng Phet Province, Thailand from 1994 and 2010. A pooled cross-sectional dataset developed by the Armed Forces Research Institute of Medical Sciences (AFRIMS) located in Bangkok, Thailand was used for the analysis. The dataset consisted of 6,240 serum samples collected from patients seen at the Kamphaeng Phet Province Hospital from 1994 to 2010. A dramatic shift in the average age of patients testing positive for dengue infection was documented from 8.6 to 17.0 years of age between years 1994 and 2010. Significant differences were also found between consecutive years and distinct year groups. The results of this study are the first to document an increase in dengue age incidence using laboratory confirmation over a 17 year period of time in Thailand. This evidence has implications for the dengue vaccine development and implementation process and clinical practice guidelines for both diagnosis and treatment as the age of infection increases.