COVID-19: How useful are travel restrictions in curbing spread?

Travel bans make sense only in the beginning of a pandemic, say experts

By Taran Deol
Published: Monday 20 December 2021
COVID-19: How useful are travel restrictions in curbing spread? Photo: Adene Sanchez / iStock

South Africa’s quick action on the isolation and sequencing of the new SARS-CoV-2 variant omicron and its decision to share this information with the world has helped global health experts build containment strategies. But the country also found itself on the receiving end of travel restrictions by governments across the world for the same reason. 

Several countries including the United States, Canada, the United Kingdom and the European Union were quick to impose bans on economic activities and travellers from South Africa, even as the origin of the new strain remained unclear. 

South African Prime Minister Cyril Ramaphosa repeatedly called for removing these restrictions. “The only thing the prohibition on travel will do is further damage the economies of the affected countries and undermine their ability to respond to, and recover from, the (novel coronavirus disease COVID-19) pandemic,” he told the media on November 28, 2021. 

Travel restrictions and bans at the beginning of the pandemic were justified because the world knew so little about the virus back then, according to public health experts.  

However, as we enter the third year of the pandemic, it is evident that travel restrictions alone are not enough to curb the spread of COVID-19 cases, established studies. 

Despite this knowledge, countries continue to impose travel restrictions, with France being the latest to allow only essential travel to and from the United Kingdom, since it started witnessing a record number of cases daily. 

A growing body of research points to reducing efficacy of travel bans with the progress of the pandemic.

By September 2020, travel restrictions were likely to have had a smaller impact on local epidemics than in May, according to a study published in Lancet December 2020. The paper analysed the effect of internationally imported cases on the internal spread of COVID-19 based on data from 162 countries. 

New Zealand and China — where the contagion has been brought under control —  may have to prevent entry of all international travelers. But this is not the case for all countries, according to the report. It stated:

In most of the countries where the proportion of imported cases is greater than 1 per cent, it can be brought to less than 1 per cent with selective restrictions imposed only on travellers from the highest-prevalence countries.

Meanwhile, countries like Brazil and Mexico — which witnessed a huge outbreak in 2020 — are less likely to benefit from such a move, the authors wrote.

Another study, published in Science in April 2020, explored the importance of the timing of imposing travel restrictions. Focusing on Wuhan and the rest of China, it noted that “the travel quarantine around Wuhan has only modestly delayed the spread of disease to other areas of mainland China.”

The ban was initially effective but has no real consequences unless coupled with public health and social distancing measures, the researchers observed. “In spite of strict travel restrictions to and from mainland China, cases in the country continued to rise.” 

Travel restrictions to COVID-19–affected areas are likely to have modest effects and transmission reduction interventions will provide the greatest benefit for mitigating the epidemic, the study noted.

Travel restrictions are effective only at the beginning of the pandemic, yet another study published in Nature this June concurred. “If there are several local outbreaks within a country, imported cases are less likely to add to the spread.

The effectiveness of travel restrictions is related to the geographical areas’ capability to cut possible disease propagation paths from existing local outbreaks to other countries, the study notes.

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