Travel restrictions are a widely-used tool by governments to prevent the spread of infectious diseases and protect citizens from exposure. They may be implemented when there is an elevated risk for disease in an area, or when certain individuals may have greater potential for becoming ill while travelling, such as pregnant women or people with chronic medical conditions.
Travel bans can be effective in decreasing the number of imported cases and slowing disease spread, but they may have unintended consequences on local healthcare systems. For instance, they restrict people’s ability to access health care and support for their families; additionally, they cause a decline in tourism – detrimental both economically and qualitatively – which has an adverse effect on quality of life.
Travel restrictions can be effective depending on when and how they are implemented, as well as the severity of a disease. Studies have indicated that travel restrictions are most successful during early stages of pandemics when diseases are locally contained and easily detectable.
With COVID-19, many countries implemented travel restrictions at the start of the pandemic – such as mainland China, Taiwan, Russia and Macau – but these measures were often too late to be effective.
Therefore, it is critical to assess the effectiveness of these measures as soon as possible. This study quickly reviews evidence on a range of travel measures taken during the early stage of COVID-19 pandemic and determines whether they reduced transmission or local epidemics.
We used a simulation model to assess the effect of travel restrictions on COVID-19 spread in various geographic areas as of June 2020. The model is composed of three parts: (a) means of lost passenger influx; (b) arrival time delay (ATD) and infected case reduction (ICR); and (c) increase in country distancing increase.
The simulation data in the above figure was generated using an online platform that replicates data from the Centers for Disease Control and Prevention (CDC). They were based on arrival times and infected cases at each given range of CDC’s infection rate in each geographical area as of 1 June 2020.
As seen on the global map, 184 areas imposed 476 entry bans during the first six months of the pandemic. These restrictions prevented noncitizens from entering certain geographic regions such as mainland China, South Korea, Japan and Iran.
However, these entry bans did not appear to significantly slow the spread of COVID-19 in affected countries; rather, they only added to the already significant loss in passenger influx.
Furthermore, we examined the impact of travel restrictions on domestic trips. Our models assume that domestic trips alter local infection rates, so travel restrictions could reduce infected cases in a given geographic area by decreasing the number of cases brought home from elsewhere.
This map depicts how various travel restrictions impact airline passenger numbers in various ways. The dotted links show the number of air passengers in each colored area when that region enforces an entry ban, global travel ban or lockdown.