Travel restrictions and sars-cov-2 transmission: An effective distance approach to estimate impact

Shi S.,
Tanaka S.,
Ueno R.,
Gilmour S.,
Tanoue Y.,
Kawashima T.,
Nomura S.,
Eguchi A.,
Miyata H.,
Yoneoka D.
Document Type
Source Title
Bulletin of the World Health Organization
World Health Organization


Objective To estimate the effect of airline travel restrictions on the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) importation. Methods We extracted passenger volume data for the entire global airline network, as well as the dates of the implementation of travel restrictions and the observation of the first case of coronavirus disease (COVID-19) in each country or territory, from publicly available sources. We calculated effective distance between every airport and the city of Wuhan, China. We modelled the risk of SARS-CoV-2 importation by estimating survival probability, expressing median time of importation as a function of effective distance. We calculated the relative change in importation risk under three different hypothetical scenarios that all resulted in different passenger volumes. Findings We identified 28 countries with imported cases of COVID-19 as at 26 February 2020. The arrival time of the virus at these countries ranged from 39 to 80 days since identification of the first case in Wuhan. Our analysis of relative change in risk indicated that strategies of reducing global passenger volume and imposing travel restrictions at a further 10 hub airports would be equally effective in reducing the risk of importation of SARS-CoV-2; however, this reduction is very limited with a close-to-zero median relative change in risk. Conclusion The hypothetical variations in observed travel restrictions were not sufficient to prevent the global spread of SARS-CoV-2; further research should also consider travel by land and sea. Our study highlights the importance of strengthening local capacities for disease monitoring and control. © 2020, World Health Organization. All rights reserved.

Migration angle
Region/Country (by coverage)
Index Keywords

air transportation; arrival time; disease transmission; epidemic; health risk; regulatory approach; social impact; travel behavior; viral disease; 2009 H1N1 influenza; Article; coronavirus disease 2019; government; human; mathematical model; risk factor; risk reduction; Severe acute respiratory syndrome coronavirus 2; survival time; travel; virus transmission; aircraft; airport; Betacoronavirus; communicable disease control; Coronavirus infection; legislation and jurisprudence; pandemic; procedures; risk assessment; statistical model; time factor; virus pneumonia; China; Hubei; Wuhan; Coronavirus; SARS coronavirus; Aircraft; Airports; Betacoronavirus; Communicable Disease Control; Coronavirus Infections; Humans; Models, Statistical; Pandemics; Pneumonia, Viral; Risk Assessment; Time Factors; Travel