Synchronized travel restrictions across cities can be effective in COVID-19 control

Haiyan Liu; Xuemei Bai; Huanfeng Shen; Xiaoping Pang; Zeyu Liang; Yue Liu

The correlation coefficients between the same mobility pattern and the number of confirmed cases are different in Stages One and Two. In Stage One, the coefficients between the population inflow from Wuhan and other cities in Hubei and the number of confirmed cases (r=0.717 and 0.739 respectively, p<0.01) are higher than those of population migration from cities outside Hubei and than intra-city population movement (r=0.650 and 0.597 respectively, p<0.01), indicating the leading role of imported cases in this time period. In Stage Two, the correlations between mobility patterns and the number of confirmed cases (r<0.5, p<0.01) weaken compared to those in Stage One (r>0.55, p<0.01), suggesting the effects of mobility on epidemic spread might be reduced due to local travel restrictions. Meanwhile, the relationship between population migration from cities outside Hubei and intra-city population movement changes from highly correlated (r=0.812, p<0.01) to moderately correlated (r=0.465, p<0.01), implying the different strictness of inter-city and intra-city travel bans. The best-fitting linear regression models for epidemic development in both Stage One and Stage Two are listed in Table 2 . In Stage One, three inter-city mobility patterns, together with the number of initial confirmed cases, could explain 73.3% of the inter-city differences in newly reported infections in cities outside Hubei. The intra-city population movement figure is highly correlated with the inflow from cities outside Hubei (r=0.812, p<0.01), but its impact on the local epidemic development is less than the inter-city scenario. This result implies the existence of imported cases from cities outside Hubei. In Stage Two, intra-city population movement and the number of initial confirmed cases could explain 51.0% of the inter-city differences in newly reported infections in cities outside Hubei. The impact of inter-city population movement is not significant in this period. . CC-BY-NC-ND 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity.