Do COVID-19 travel restrictions prevent spread?

A study is looking into whether travel restrictions help prevent the spread of COVID-19.

After the first pandemic declaration in March 2020, pharmaceutical companies rushed to research and develop a vaccine. In the meantime, many countries have put international travel restrictions in place in the 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 in China, Iran, and Italy, where outbreaks first occurred. As the virus spread, so too did 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. Restrictions included border closings, flight closures, quarantine, and self-isolation requirements. Travel restrictions are known to have a high social and economic impact. Social impacts result from missed opportunities to visit friends and families, while economic impacts result from loss of tourist travel. Experts recommend implementing travel restrictions only if their benefits outweigh these costs.

To determine the effectiveness of travel restrictions, researchers from the COVID-19 working group at the Center for Mathematical Modeling of Infectious Diseases examined the cases expected from international travel. Their results were published in The Lancet magazine.

The researchers collected estimates of COVID-19 in departure and arrival countries in May and September 2020 and combined these with flight data. A risk assessment was then drawn up for each country.

When the risk score was rated high based on the number of cases imported and the number of locally reported cases, the researchers found that travel restrictions would have a huge impact on controlling the spread of the virus. The lower the risk rating, the less value travel restrictions were expected to be.

The study found that as of May 2020, travel restrictions were useful as imported cases would have contributed 10% or more of the cases. However, as of September 2020, travel restrictions in low risk countries did little to reduce prevalence.

This does not mean that travel restrictions are not worthwhile, but it does show that strict, blanket restrictions are not always necessary. The study suggests that a detailed assessment of health and travel data must be thoroughly reviewed before travel restrictions for COVID-19 are enforced.

Written by: Rebecca K. Blankenship, B.Sc.

Reference:

1. Russell T., Wu J., Clifford S., Edmunds W., Kucharski A., Jit M. Effect of internationally imported cases on the internal spread of COVID-19: a mathematical model study. The Lancet Public Health. 2021; 6 (1): e12-e20. doi: 10.1016 / s2468-2667 (20) 30263-2

Image by Miroslava Chrienova from Pixabay