Countries have restricted international arrivals to delay the spread of COVID-19. These measures carry a high economic and social cost. They may have little impact on COVID-19 epidemics if there are many more cases resulting from local transmission compared to imported cases. To inform decisions about international travel restrictions, we compared the ratio of expected COVID-19 cases from international travel (assuming no travel restrictions) to the expected COVID-19 cases arising from internal spread on an average day in May 2020 in each country. COVID-19 prevalence and incidence were estimated using a modelling framework that adjusts reported cases for under-ascertainment and asymptomatic infections. The data used in this analysis is publicly available case and death time series data, available from the European Centre for Disease Control 10. The code used for the analysis in this paper is available online (https://github.com/thimotei/covid_travel_restrictions), as is the code used to produce under-reporting estimates, which form the basis for the country-specific prevalence and incidence estimates (https://github.com/thimotei/covid_underreporting)

COVID-19, Coronavirus, SARS-CoV2, Travel restrictions