Effect of Travel Restrictions of Wuhan City Against COVID-19: A Modified SEIR Model Analysis

Abstract

Objective: Since December 2019, a new coronavirus viral was initially detected in Wuhan, China. Population migration increases the risk of epidemic transmission. Here, the objective of study is to estimate the output risk quantitatively and evaluate the effectiveness of travel restrictions of Wuhan city.

Methods: We proposed a modified susceptible-exposed-infectious-recovered (SEIR) dynamics model to predict the number of coronavirus disease 2019 (COVID-19) symptomatic and asymptomatic infections in Wuhan. And, subsequently, we estimated the export risk of COVID-19 epidemic from Wuhan to other provinces in China. Finally, we estimated the effectiveness of travel restrictions of Wuhan city quantitatively by the export risk on the assumption that the measure was postponed.

Results: The export risks of COVID-19 varied from Wuhan to other provinces of China. The peak of export risk was January 21-23, 2020. With the travel restrictions of Wuhan delayed by 3, 5, and 7 d, the export risk indexes will increase by 38.50%, 55.89%, and 65.63%, respectively.

Conclusions: The results indicate that the travel restrictions of Wuhan reduced the export risk and delayed the overall epidemic progression of the COVID-19 epidemic in China. The travel restrictions of Wuhan city may provide a reference for the control of the COVID-19 epidemic all over the world.

Keywords: COVID-19; SEIR model; export risk; migration indexes.

Figure 1.

Diagram of the model adopted for COVID-19 simulation based on the epidemiological characteristics.

Figure 2.

The distribution of confirmed cases and population emigration index of Wuhan (The population emigration indexes from Wuhan were in January 2020 and the same period of the lunar calendar in 2019. The Spring Festival was on January 25, 2020).

Figure 3.

The theoretical predicted value of the number of symptomatic infection and asymptomatic patients based on the modified SEIR model (I: infected person with symptoms; A: asymptomatic infections).

Figure 4.

Standardized export risk of COVID-19 epidemic from Wuhan to provinces in China (The standardized risk coefficients of provinces ranged with travel restrictions of Wuhan city are presented in panel A in the early stage of the epidemic; The standardized risk coefficients of provinces ranged without travel restrictions of Wuhan city until January 30 are presented in panel B in the early stage of the epidemic.).

Figure 5.

Spearman correlation coefficient between the standardized total input risk coefficients and the cumulative number of confirmed cases in provinces of China.

Figure 6.

Export risk from Wuhan to part of the provinces (20 provinces with higher risk factors) when the travel restrictions of Wuhan city were implemented at different times.