Spatiotemporal characteristics of seasonal influenza in mainland China

OBJECTIVE: To study the spatiotemporal distribution and seasonal characteristics of influenza and to explore its transmission patterns, in the mainland of China. METHODS: Spatiotemporal cluster methods and spatial trend surface methods were used to analyze the influenza surveillance data. RESULTS: There were a summer peak in the south from June to August (RR(paediatric) = 1.31, P < 0.01; RR(internal) = 1.74, P < 0.01) and a winter peak from December to January (RR(paediatric) = 1.45, P < 0.01; RR(internal) = 1.45, P < 0.01) in the northern part of the country, during every epidemic season. Influenza virus in mainland China seemed to spread from the southern to the northern parts of the country, in a progressing way. CONCLUSION: In the southern part of the country, it is more important to take prevention and control measurements on influenza from June to August but for the northern part, the key period is from December to January. It is more important to timely identify the variation of the influenza virus, in the southern part of the country.