Study examines whether travel restrictions help prevent spread of COVID-19.
After the initial pandemic declaration in March 2020, pharmaceutical companies rushed to research and create a vaccine. In the meantime, many countries implemented international travel restrictions in hopes that they would delay the spread of the virus. It was also hoped that travel restrictions would prevent overwhelming health systems.
The earliest travel restrictions were imposed in China, Iran, and Italy where outbreaks first occurred. As the virus spread, so too did the travel restrictions. By April 20, 2020 every country in the world had imposed travel restrictions due to COVID-19.
Travel restrictions varied based on the stage of COVID-19 progression. The restrictions included border closures, flight suspension, quarantine, and self-isolation requirements. Travel restrictions are known to have high social and economic impact. Social impact comes from lost opportunities for visiting friends and families, while economic impact comes from loss of tourism travel. Experts recommend travel restrictions only be implemented when their benefits outweigh these costs.
To determine the effectiveness of travel restrictions, researchers from the Centre for the Mathematical Modelling of Infectious Diseases COVID-19 working group researched the cases expected from international travel. Their results were published in the journal, The Lancet.
Researchers collected estimates of COVID-19 in departure and arrival countries in May and September 2020 and combined it with flight data. From this a risk rating for each country was created.
If the risk rating was deemed to be high based on the number of cases imported and the number of cases reported locally, researchers determined that travel restrictions would have a high impact on controlling the virus spread. The lower the risk rating, the less value travel restrictions were expected to have.
The study suggested that in May 2020 travel restrictions were useful because imported cases would have contributed to 10% or more of the cases occurring. However, by September 2020 in countries with low risk rating the travel restrictions did little to reduce spread.
This does not suggest that travel restrictions are not worthwhile but shows that strict blanket restrictions are not always necessary. The study does suggest a detailed assessment of health and travel data must be thoroughly assessed prior to enforcing travel restrictions for COVID-19.
Written by: Rebecca K. Blankenship, B.Sc.
1. Russell T, Wu J, Clifford S, Edmunds W, Kucharski A, Jit M. Effect of internationally imported cases on internal spread of COVID-19: a mathematical modelling study. The Lancet Public Health. 2021;6(1):e12-e20. doi:10.1016/s2468-2667(20)30263-2
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