Policies for Easing COVID-19 Pandemic Travel Restrictions

Abstract

During the COVID-19 pandemic, many countries implemented international travel restrictions that aimed to contain viral spread while still allowing necessary cross-border travel for social and economic reasons. The relative effectiveness of these approaches for controlling the pandemic has gone largely unstudied. Here we developed a flexible network meta-population model to compare the effectiveness of international travel policies, with a focus on evaluating the benefit of policy coordination. Because country-level epidemiological parameters are unknown, they need to be estimated from data; we accomplished this using approximate Bayesian computation, given the nature of our complex stochastic disease transmission model. Based on simulation and theoretical insights we find that, under our proposed policy, international airline travel may resume up to 58% of the pre-pandemic level with pandemic control comparable to that of a complete shutdown of all airline travel. Our results demonstrate that global coordination is necessary to allow for maximum travel with minimum effect on viral spread.

Figure 1:

Model fit for different countries. For each country, the fit is demonstrated by the number of accumulated confirmed cases and the accumulated death confirmed. In each plot, the red line is the real data, the blue line is the median fitted values, and the shaded region is the 95% confidence interval. BRA, Brazil; ESP, Spain; FRA, France; GBR, Great Britain; IND, India; ITA, Italy, RUS, Russia; USA, United States.

Figure 2:

(A) Prediction of the average number of undetected infected cases for different travel regulation policies. “Fully open” indicates no travel restrictions are in place, “Fully closed” indicates no travel is permitted, and “Average control” denotes our proposed policy whereby the number of daily undetected infected cases stays below a threshold of c = 70 (the dashed line) on average. (B) Scatter plot for the relative change in total new cases for each country in the two most extreme scenarios: fully closed and fully open. The 97.5th percentile value of relative change in each country’s new cases under the fully closed scenario (x-axis) is plotted versus the fully open scenario (y-axis). The closer a country is to the reference line x = y, the less benefit that country gains from travel restrictions.