Establishment of early warning model of hand, foot and mouth disease based on moving epidemic method in Chongqing

  Objective  To evaluate the feasibility of establishing an early warning model of hand, foot and mouth disease (HFMD) based moving epidemic method (MEM) in Chongqing.

  Methods  The incidence data of HFMD in Chongqing from the 1^st week of 2013 to the 26^th week of 2019 were collected from Chinese Infectious Disease Information System. Two peaks of HFMD were found by plotting the epidemic curve of the average incidence of HFMD. The spring-summer MEM model and the autumn-winter MEM model were then established respectively, and the parameters δ of models were screened. The fitting effect of two models were evaluated by using sensitivity, specificity and Yoden index. The models were used to predict the incidence of HFMD in Chongqing in 2018/2019.

  Results  The results showed that the epidemic period in spring and summer lasted from the 13^th week 36^th weeks in 2019, and the epidemic period in autumn and winter lasted from the 36^th week in 2018 to the 2^nd week in 2019. The optimal parameter of MEM model during spring-summer was 2.6, the sensitivity, specificity and Yoden index were 0.883, 0.908 and 0.791, respectively. The optimal parameter of MEM model during autumn-winter was 2.4, and the sensitivity, specificity and Yoden index were 0.805, 0.862 and 0.667. Most counties and districts of Chongqing had similar incidence level of HFMD.

  Conclusion  Establishing MEM models by dividing two incidence peaks of HFMD into single one respectively can accurately identify the epidemic period of HFMD, and the models can be used for the early warning of HFMD in Chongqing.