Estimating the prevalence and risk of COVID-19 among international travelers and evacuees of Wuhan through modeling and case reports

Luo G.,
McHenry M.L.,
Letterio J.J.
Document Type
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Public Library of Science


Coronavirus disease 2019 (COVID-19) started in Wuhan, China and has spread through other provinces and countries through infected travelers. On January 23rd, 2020, China issued a quarantine and travel ban on Wuhan because travelers from Wuhan were thought to account for the majority of exported COVID-19 cases to other countries. Additionally, countries evacuated their citizens from Wuhan after institution of the travel ban. Together, these two populations account for the vast majority of the "total cases with travel history to China"as designated by the World Health Organization (WHO). The current study aims to assess the prevalence and risk of COVID-19 among international travelers and evacuees of Wuhan. We first used case reports from Japan, Singapore, and Korea to investigate the date of flights of infected travelers. We then used airline traveler data and the number of infected exported cases to correlate the cases with the number of travelers for multiple countries. Our findings suggest that the risk of COVID-19 infection is highest among Wuhan travelers between January 19th and 22nd, 2020, with an approximate infection rate of up to 1.3% among international travelers. We also observed that evacuee infection rates varied heavily between countries and propose that the timing of the evacuation and COVID-19 testing of asymptomatic evacuees played significant roles in the infection rates among evacuees. These findings suggest COVID-19 cases and infectivity are much higher than previous estimates, including numbers from the WHO and the literature, and that some estimates of the infectivity of COVID-19 may need re-assessment. © 2020 Luo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Article; China; controlled study; coronavirus disease 2019; disease transmission; human; infection rate; Japan; Korea; population research; prevalence; risk factor; Singapore; travel; World Health Organization; aircraft; asymptomatic infection; biological model; communicable disease control; Coronavirus infection; pandemic; prevalence; virus pneumonia; Aircraft; Asymptomatic Infections; China; Communicable Disease Control; Coronavirus Infections; Disease Transmission, Infectious; Humans; Models, Biological; Pandemics; Pneumonia, Viral; Prevalence; Travel