Estimating number of global importations of COVID-19 from Wuhan, risk of transmission outside mainland China and COVID-19 introduction index between countries outside mainland China

Haoyang Sun; Borame Lee Dickens; Mark Chen; Alex Richard Cook; Hannah Eleanor Clapham

For each recipient country or territory outside mainland China, we assess the relative potential of COVID-19 introduction from each donor country that has a local outbreak risk estimate exceeding 50%. For example, Hong Kong, Singapore, and Australia are found to have the highest COVID-19 introduction index estimates when we consider the United Kingdom as the recipient country. Using the United Kingdom, United States, South Korea, and South Africa as recipient country examples, we highlight the top donor countries or territories based on the COVID-19 introduction index estimate for each of these countries (Figure 3 ). The COVID-19 introduction index estimates for all pairs of donor-recipient countries create a network of ranked possible importation links between countries outside mainland China (Table S3A ). The total COVID-19 introduction index estimate from all the potential donor countries is highest for Taiwan followed by Japan (full list of estimates shown in Table S3B ).