Importation of SARS-CoV-2 infection leads to major COVID-19 epidemic in Taiwan

Lin, Chih-Yen; Wang, Wen-Hung; Urbina, Aspiro Nayim; Tseng, Sung-Pin; Lu, Po-Liang; Chen, Yen-Hsu; Yu, Ming-Lung; Wang, Seng-Fan

Abstract Objective COVID-19 has recently become a pandemic affecting many countries worldwide. This study aims to evaluate current status of COVID-19 in Taiwan and analyze the source of infection. Methods National data regarding SARS-CoV-2 infection were obtained from Taiwan CDC at the end of April, 2020. These data were subjected for analysis of the current status and correlation between indigenous and imported COVID-19 cases. Phylogenetic tree was performed to analyze the phylogeny of Taiwanese SARS-CoV-2 isolates. Results The initial case of SARS-CoV-2 infection in Taiwan was detected on January 21, 2020. Epidemiological data indicate that by April 30, there were a total of 429 COVID-19 confirmed cases with the death rate of 1.3%. Most of cases were identified as imported (79.9%; 343/429) with majority transmitted from United States of America (22.1%) and United Kingdom (17.6%). Results from phylogenetic tree analyses indicate that the Taiwanese SARS-CoV-2 isolates were clustered with the SARS-CoV-2 isolates from other countries (bootstrap value 98%) and sub-clustered with bat SARS-like coronaviruses (bootstrap value 99%). Conclusion This study suggests that importation of SARS-CoV-2 infection was the primary risk-factor resulting in the COVID-19 epidemic in Taiwan.