By now, the recommended measures for reducing the likelihood of being infected by SARS-CoV-2, the virus that is the cause of COVID-19, are well known. The list varies, depending on the source. But, the most frequent recommendations are to wash hands, avoid touching the face, social isolation, and cancel travel plans.
For some, the last in the list may not be a choice. Certain areas of the world (such as Wuhan in Hubei province and regions of Italy) have imposed quarantines or looser travel restrictions that make moving around difficult to impossible.
But how useful is the recommendation to not travel in combating the spread of the virus? An international group from institutions including Northeastern University in Boston, MA, the Bruno Kessler Foundation and the ISI Foundation in Italy, the Fogarty International Center at NIH, Fudan University in Shanghai, China, the Fred Hutchinson Cancer Research Center, the University of Washington in Seattle, WA, and the University of Florida, took on the effectiveness that travel restrictions in Wuhan, China, specifically, had on the spread of the COVID-19 outbreak.
The work is published in Science in an article titled, “The effect of travel restrictions on the spread of the 2019 novel coronavirus (COVID-19) outbreak.”
The modeling study estimates the impacts of COVID-19’s spread in and beyond China after the establishment of quarantine in the Chinese city of Wuhan. To understand the impacts of these measures on the dynamics of COVID-19 spread, Matteo Chinazzi, PhD, associate research scientist at Northeastern University and colleagues used a global disease transmission model known as “GLEAM” to project the impact of travel limitations on the national and international spread of the epidemic. The model is calibrated based on internationally reported cases and shows that at the start of the travel ban from Wuhan on January 23, most Chinese cities had already received many infected travelers.
The team’s results show that the travel ban introduced in Wuhan on January 23 delayed progression of the epidemic throughout Mainland China by three to five days—a modest effect.
The authors extrapolate that to say that the greatest benefit to mitigating the epidemic will come from public health interventions and behavioral changes—factors like early detection, isolation, and handwashing.
When airlines halted flights to and from China starting in early February, this restriction initially helped to slow spread of COVID-19 elsewhere in the world. Though, even in the case of 90% travel reductions, the number of imported cases in other countries went up significantly in a matter of weeks from cases that originated elsewhere, if transmissibility was not reduced through efforts like self-isolation, the authors said.
The travel limitations, they noted, have a modest effect unless paired with public health interventions and behavioral changes that achieve a considerable reduction in the disease transmissibility.
They added that even in the presence of the strong travel restrictions in place to and from Mainland China since January 23, a large number of individuals exposed to the virus had been traveling internationally without being detected. “Moving forward we expect that travel restrictions to COVID-19 affected areas will have modest effects, and that transmission-reduction interventions will provide the greatest benefit to mitigate the epidemic,” they said.
These results may help inform scientists, public health personnel, and policymakers involved in the global response to the epidemic.