Transmission center and driving factors of hand, foot, and mouth disease in China: A combined analysis.

Hand, foot, and mouth disease (HFMD) has become a major public health issue in China. The disease incidence varies substantially over time and across space. To understand the heterogeneity of HFMD transmission, we compare the spatiotemporal dynamics of HFMD in Qinghai and Shanghai by conducting combined analysis of epidemiological, wavelet time series, and mathematical methods to county-level data from 2009 to 2016. We observe hierarchical epidemic waves in Qinghai, emanating from Huangzhong and in Shanghai from Fengxian. Besides population, we also find that the traveling waves are significantly associated with socio-economic and geographical factors. The population mobility also varies between the two regions: long-distance movement in Qinghai and between-neighbor commuting in Shanghai. Our findings provide important evidence for characterizing the heterogeneity of HFMD transmission and for the design and implementation of interventions, such as deploying optimal vaccine and changing local driving factors in the transmission center, to prevent or limit disease spread in these areas. Author summary Hand, foot, and mouth disease (HFMD) has been a concern in Asian regions since the late 1990s. To disclose the transmission mechanism of HFMD and its driving factors, we combined epidemiological, spatial, and mathematical analysis, using HFMD cases in two provinces (Qinghai and Shanghai) of China as an example. We found the phenomenon of traveling waves in the process of HFMD transmission for the first time and identified different types of traveling waves associated with different driving factors. HFMD in Qinghai decline year by year with the characteristics of cross-region population mobility, while epidemics in Shanghai are persistent in the suburban areas with low incidence in the urban areas and neighboring population movement dominates the pattern. Our findings facilitate the understanding of HFMD transmission mechanisms over geographic regions, which are crucial for designing a jointly effective HFMD prevention and control strategy.