Epidemiologic features of Kawasaki disease distinguished by seasonal variation: an age-specific analysis.

PURPOSE: The purpose of this study was to review the seasonal variation of Kawasaki disease (KD) by an age-specific analysis to clarify the distribution of infectious agents.

METHODS: Data obtained from nationwide surveys of KD in Japan, which targeted patients for 12 years (2003-2014), were analyzed. The monthly numbers of patients were classified into the following age groups: 0-11 months, 1 year, 2-3 years 5 months, and 3 years 6 months-4 years. Factors associated with disease onset were analyzed using a 12-month moving average method.

RESULTS: In winter, a sharp peak was observed in all age groups, but this was notably sharper in the 1-year age group. Plateaus in disease occurrence were observed in two periods: from March to May in the 2- to 4-year age group and from June to August in the 0- to 11-month age group. Seasonal index was analyzed into two factors that differed depending on the age group.

CONCLUSIONS: The age-specific analysis of KD clearly identified age-related differences in the seasonal occurrence of this disease.