Is it safe to lift COVID-19 travel bans? The Newfoundland story

Abstract

A key strategy to prevent a local outbreak during the COVID-19 pandemic is to restrict incoming travel. Once a region has successfully contained the disease, it becomes critical to decide when and how to reopen the borders. Here we explore the impact of border reopening for the example of Newfoundland and Labrador, a Canadian province that has enjoyed no new cases since late April, 2020. We combine a network epidemiology model with machine learning to infer parameters and predict the COVID-19 dynamics upon partial and total airport reopening, with perfect and imperfect quarantine conditions. Our study suggests that upon full reopening, every other day, a new COVID-19 case would enter the province. Under the current conditions, banning air travel from outside Canada is more efficient in managing the pandemic than fully reopening and quarantining 95% of the incoming population. Our study provides quantitative insights of the efficacy of travel restrictions and can inform political decision making in the controversy of reopening.

Global and local mobility as a barometer for COVID-19 dynamics

“…While global mobility as in Fig. S4 can be an important modulator at very low or zero case numbers ( 18 ), our study suggests that a country-specific analysis based on local mobility alone as in Fig. 3 is probably sufficient to explain the major outbreak dynamics.…”

“…We draw the COVID-19 outbreak data for 26 European countries from the reported confirmed cases from February 24, 2020 ( 21 ). From these data, we extract the new reported cases, Δ Î ( t ) = I ( t n+1 ) − I ( t n ), as the difference between today’s and yesterday’s reported cases ( 18 ). To estimate global mobility, we use the passenger air travel data between any two European countries ( 22 ), normalized by the baseline mean air travel volume from 15 January to 15 February 2020 ( 24 ).…”

Data-driven modeling of COVID-19—Lessons learned

“…There is a legitimate fear that easing off travel restrictions, even slightly, could trigger a new outbreak and accelerate the spread to an unmanageable degree. As we are trying to identify exit strategies from local lockdowns and global travel restrictions, political decision makers are turning to mathematical models for quantitative insight and scientific guidance [46] .…”

“…This implies that every five days and every three days, an exposed and an infectious traveler would enter the province of Newfoundland and Labrador. In other words, every other day, a new COVID-19 case would enter the Newfoundland and Labrador via air travel [46] . Since the exposed and early infectious individuals are still pre-symptomatic, it is impossible to identify and isolate them without strict quarantine requirements [49] .…”

“…Predictions are based on a local SEIR model using the mean effective reproduction number of 1.35 for all of North America, solid lines, and 1.16 for Canada, dashed lines, on the day of opening. The black horizontal line marks 0.1% of the population of Newfoundland and Labrador [46] . …”