Travel-related Importation and Exportation Risks of SARS-CoV-2 Omicron Variant in 367 Prefectures (Cities) - China, 2022

Yuan Bai; Mingda Xu; Caifen Liu; Mingwang Shen; Lin Wang; Linwei Tian; Suoyi Tan; Lei Zhang; Petter Holme; Xin Lu; Eric H Y Lau; Benjamin J Cowling; Zhanwei Du

doi:10.46234/ccdcw2022.184

Travel-related Importation and Exportation Risks of SARS-CoV-2 Omicron Variant in 367 Prefectures (Cities) - China, 2022

China CDC Wkly. 2022 Oct 7;4(40):885-889. doi: 10.46234/ccdcw2022.184.

Authors

Yuan Bai¹, Mingda Xu², Caifen Liu^{1

2}, Mingwang Shen³, Lin Wang⁴, Linwei Tian¹, Suoyi Tan⁵, Lei Zhang³, Petter Holme^{6

7}, Xin Lu⁵, Eric H Y Lau^{1

2}, Benjamin J Cowling^{1

2}, Zhanwei Du^{1

2}

Affiliations

¹ WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
² Laboratory of Data Discovery for Health Limited (D24H), Hong Kong Science Park, Hong Kong Special Administrative Region, China.
³ China-Australia Joint Research Center for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an City, Shaanxi Province, China.
⁴ Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK.
⁵ College of Systems Engineering, National University of Defense Technology, Changsha City, Hunan Province, China.
⁶ Department of Computer Science, Aalto University, Espoo, Finland.
⁷ Center for Computational Social Science, Kobe University, Kobe, Japan.

Abstract

Introduction: Minimizing the importation and exportation risks of coronavirus disease 2019 (COVID-19) is a primary concern for sustaining the "Dynamic COVID-zero" strategy in China. Risk estimation is essential for cities to conduct before relaxing border control measures.

Methods: Informed by the daily number of passengers traveling between 367 prefectures (cities) in China, this study used a stochastic metapopulation model parameterized with COVID-19 epidemic characteristics to estimate the importation and exportation risks.

Results: Under the transmission scenario (R₀ =5.49), this study estimated the cumulative case incidence of Changchun City, Jilin Province as 3,233 (95% confidence interval: 1,480, 4,986) before a lockdown on March 14, 2022, which is close to the 3,168 cases reported in real life by March 16, 2022. In a total of 367 prefectures (cities), 127 (35%) had high exportation risks according to the simulation and could transmit the disease to 50% of all other regions within a period from 17 to 94 days. The average time until a new infection arrives in a location in 1 of the 367 prefectures (cities) ranged from 26 to 101 days.

Conclusions: Estimating COVID-19 importation and exportation risks is necessary for preparedness, prevention, and control measures of COVID-19 - especially when new variants emerge.

Keywords: COVID-19; Importation and exportation risks; Omicron.

Copyright and License information: Editorial Office of CCDCW, Chinese Center for Disease Control and Prevention 2022.

Grants and funding

Supported by AIR@InnoHK programme from The Innovation and Technology Commission of the Hong Kong Special Administrative Region, National Natural Science Foundation of China (72104208), JSPS KAKENHI (JP21H04595), National Nature Science Foundation of China (72025405, 91846301, 72088101, and 71790615)