基于人口流动的海南省新型冠状病毒肺炎输入风险和防控效果评估

目的对海南省各市县2020年1月10日—3月7日新型冠状病毒肺炎输入风险进行评估,并对2021年春运期间采取“常态化防控”措施效果进行评估。方法收集海南省每日报告输入病例数及30个省份每日报告病例数和百度迁徙指数,计算海南省各市县输入风险指数,对全省及各市县输入风险进行量化评估。分析输入风险指数与输入病例间关系,据此构建“疫情应急围堵”阶段输入病例拟合模型,预测2021年春运期间仍然采取“应急围堵”策略可能的输入病例数,与实际输入病例数相比较,以评估2021年春运期间采取“常态化”疫情防控策略的效果。结果海南省报告输入病例112例,平均输入风险指数为0.98。海口市、三亚市和儋州市输入风险最高,除海口外,各市县输入风险指数1月24日左右达到最大值,以滞后4 d和5 d输入风险指数构建的两阶段广义相加模型对输入病例数的拟合程度最好(R^(2)_(adjust1)=83.50%,R^(2)_(adjust2)=82.00%,MRE=17.61%)。如继续采取“应急围堵”策略,预计2021年春运期间海南省将有10例输入病例,“常态化”防控策略下,实际上海南省无输入病例发生。结论海口和三亚等旅游城市输入风险较高,湖北省和广东省是主要的疫情输入省份,广义相加模型可以较好地对“应急围堵”阶段海南省新冠肺炎输入病例进行拟合。与“应急围堵”策略相比较,2021年春运期间采取的“常态化”疫情防控策略使海南省减少了约10例输入病例。

Risk assessment and prevention and control effective assessment for COVID-19 in Hainan based on population migration

Objective To assess imported risk of COVID-19 in Hainan province from January 10 to March 7 in 2020, and to assess the effect of "The Normalization Prevention and Control" (measures during the Spring Festival Travel Rush (SFTR) in Hainan in 2021. Methods The daily reported imported cases in Hainan province, the daily reported cases in other 30 province of China, and the Baidu Migration Index were collected to calculated into the Imported Risk Index (IRI) to quantitatively assess the imported risk of Hainan province. Based on the analysis of the relationship between the imported risk index and imported cases, an imported case prediction model was constructed to fit the number of imported cases in "emergency containment" stage in Hainan. And number of imported cases during the Spring Festival Travel rush in 2021 was predicted by this model to compared with the actual number, which was to evaluate the "Normalization Prevention and Control" measures in this model was also used to assess the effect of "Normalization Prevention and Control" measures during the SFTR in 2021. Results Totally 112 imported cases were reported in Hainan. The average IRI was 0.98. Haikou, Sanya and Danzhou have the highest imported risk. Except Haikou, the imported risk index of all cities and counties reached the maximum value around January 24th. The generalized additive model based on the lag 4 days and lag 5 days was best fitted with the actual imported cases number (R²_adjust1=83.50%, R²_adjust2=82.00%, MRE=17.61%). If "Emergency Containment" strategy was still adopted, there were 10 COVID-19 cases imported into Hainan during the SFTR in 2021. Under the "Normalization Prevention and Control" strategy, virtually no imported cases were found in Hainan. Conclusions Tourism cities such as Haikou and Sanya have high imported risks. Hubei and Guangdong provinces are the main imported provinces. The Generalized Additive Model based on the Imported Risk Index can better fit with the imported cases number of COVID-19 in Hainan Province in "emergency containment". Compared with the "Emergency Containment" strategy, the "Normalization Prevention and Control" strategy adopted during the SFTR in 2021 reduced imported cases in Hainan by about 10.