Seasonal synchrony in incidences of common infectious diagnoses in early childhood among neighbouring regions.

OBJECTIVES: Information on seasonal synchrony of influenza activity between neighbouring regions has been found useful for planning infection control measures. Seasonal synchrony of other infectious diseases is less known. We describe the seasonality and seasonal synchrony of three common childhood infectious diagnoses among three regions in Taiwan. METHODS: A large, nationally representative sample of young children (N=128 651, age 0-4 years) was used to estimate the monthly incidences of acute respiratory infection, acute intestinal infection, and herpangina and hand, foot, and mouth disease (HFMD) in three regions of Taiwan between 2000 and 2005. Seasonality of monthly incidences was indicated by year-on-year intra-class correlations (ICCs). Between-region ICCs were used to describe seasonal synchrony of incidences between regions. RESULTS: We found evidence of seasonality in all three infectious diagnoses (p<0.05). Seasonal synchrony among the three regions was highest for acute respiratory infection (between-region ICC 0.91, 95% confidence interval (CI) 0.87-0.94), followed by herpangina and HFMD (between-region ICC 0.85, 95% CI 0.80-0.90), and acute intestinal infection (between-region ICC 0.69, 95% CI 0.59-0.79). CONCLUSIONS: We found strong evidence of seasonal synchrony in the incidences of acute respiratory infection, acute intestinal infection, and herpangina and HFMD between three neighbouring regions of Taiwan. An understanding of these disease patterns may inform future infection control measures.